D1 - Vini and Viti Flashcards
xylem what is it
transport tissue that transfers water and some nutrients from roots to the vine
Millerandage what is and consequences
high proportion of seedless grapes (during fruit set)->reduce volume of wine and green, unripe grape lower the quality of wine
Coulure
grape bunch failed due to high proportion of flowers
phloem what is it
transport tissue that transports sugar from leaves to other parts of the vine
Early ripening grapes
Chardonnay, Pinot Noir
Late ripening grapes
Cabernet Sauvignon
Which nutrients needs for vine?
Nitrogen
Potassium
Phosphorus
Calcium
Magnesium
Mineralisation what is it
Organisms that live in the soil (bacteria, fungi, earthworm) converts manure or compost into inorganic compounds that vine can take.
What is soil?
Soil = sediment (+humus+water+air) + bedrock
Sediment - sands, pebbles, rocks - moved and deposited by wind or water
humus is an organic matter in the soil that is formed by the partial decomposition of plant and animal material by soil microbes and earthworms. It has a spongey texture, large surface area and is able to adsorb water and nutrients.
The soil in the vineyards - different layers formed at different periods of time, each of which may have different texture, structure and characteristics.
The most important physical elements of a soil are the texture and structure (suitability of the soil for viticulture will depend on the texture and structure and how far roots are able to penetrate (pass through)
Nitrogen effect on vine (growing environment)
Vigor and grape quality, NItrogen is component of protein and chlorophyll.
Too much nitrogen - excessive vegetal growth
too little nitrogen - problematic fermentation
Potassium effect on vine (growing environment)
it helps regulate flow of water in vine.
High potassium -> problem for uptake magnesium->reduce yields, poor ripening.
high potassium ->high pH in grapes
Low potassium ->low sugar accumulation (poor vine growth, reduce yields)
Phosphorus effect on vine
important for photosynthesis.
Magnesium effect on vine
found in chlorophyll and has key role in photosynthesis (deficiency can cause reduce yields and poor ripening)
What is biomass?
total quantity or weight of organisms in a given area or volume
Rootstock , which specie?
many rootstocks are hybrid of 2 different vine species (to take advantage to take both parents characteristics)
Which criteria need to consider a vine grower when choosing the rootstock?
Pests
Water
Soil pH
Vigour
low pH soil
acidic soil
high pH soil
alkaline soil or high lime content (limestone soil) (non-acidic)
what is cover crop?
other plants - for organic viticulture , for more roots - more prevent from erosion and contribute to the improvement of the life of the soil. Green manure (improving biodiversity) - access to nitrogen and carbon dioxide
What is soil texture and structure?
Texture is describes proportions of mineral particles of sand, silt and clay.
Sand - loose texture, clay - tight soil
Structure - describes mineral particles in the soil form aggregates (crumbs).
…. ???
4 factors leading to good soil health?
- Good soil structure
- abundance of organic matter and humus
- presence of living organisms
- available nutrients
5 characteristics of good soil structure?
- Good drainage
- Capacity of water retention (sufficient water-holding capacity)
- Ability to resist erosion
- Availability to penetrate the roots to sufficient depth
- Sufficient oxygen
What effect does the presence of organic matter and humus have on soil?
- decomposing organic matter supplies nutrients
- humus improves the structure of soil and its water
- holding capacity
What effect does the presence of living organisms have on soil?
earthworms and microbes break down organic matter into humus and inorganic nutrients that accessible to the vine
what can poor soil health lead to?
problems with the availability and uptake of nutrients and water in the soil leading to poor vine growth and grape ripening
Vigour of vine depends on?
vigour depends on natural resources (t°, water and nutrients), planting material (grape variety, clone, rootstock), and presence of any disease.
Six aims of canopy management?
- Maximise the effectiveness of light
- Reduce shade
- Ensure microclimate is uniform so grapes ripen evenly
- Balance between vegetative and reproductive functions
- Arrange to ease mechanisation
- Promote air circulation to reduce disease
Problems with dense canopies?
- poor air circulation
- higher humidity
- suitable condition for fungal
- fungicides will have less penetration into canopy
Six main canopy management techniques are?
- Vine training
- Vine pruning
- Site assessment to determine the ideal grape variety, rootstock visor, planting density and row orientation
- Winter pruning
- Summer pruning
- overall plant vigour management
What vineyard operations are performed during Summer Pruning?
- Shoot positioning
- Shoot removal
- pinching
- Disbudding
- Shoot trimming
- leaf removal
- green harvest
What is transpiration?
Water take from roots
Nematode resistance rootstock?
Ramsey and Dog Ridge
What is food for spider mites?
They eat surface cells of leaves
What is food for grape moths?
They eat flowers and grapes
What is food for nematodes?
Its a microscopic worms in soil, they eat vine roots.
What is food for phylloxera?
Insects - they eat vine root and lay eggs on the roots.
Symptoms of phylloxera?
- Vines die of drought in patches and next year also
- vine roots covered with insects, surrounded by yellow eggs
- Pale green galls on the under-surface of the leaves
- slow shoot growth, leaf yellow in 3 years, after 5 years plant die.
What is mulches
Mulches are usually made of biodegradable materials, such as straw or bark chips, that provide nutrients for the vine. Material with high nutrient content can be chosen for nutrient-poor vineyards.
How to treat powdery mildew?
- open canopy
- fungicides
- sulfur (spray from 2nd week of bud burst until veraison)
What are fungal name (caused) for Powdery mildew, Downy mildew, Grey rot?
PM - Erysophe (Odium tucker)
DM - Peronospora
GR - Botrytis Cinerea
Name 2 virus diseases?
Fanleaf virus
Leafroll virus
Fanleaf virus how spread and behave?
Discoloration, late or delay shoot, and leafs looks like a fan.
Spread: grafting and dagger nematodes
Prevent: no cure, check the soil virus-test the soil for presence of dagger nematodes, clean planting material
what is phloem?
transport tissue that transports sugar from leaves to other parts of the vine)
Tool that measures the sugar level in the grape?
refractometer
How to stop or prevent MLF?
- Add enzyme lysozyme (kills lactic acid bacteria)
- move out to other part of winery
- filter out lactic acid bacteria
Conditions that stop or prevent MLF?
- t below 15 C
- low pH
- moderate SO2
Reverse osmosis?
Cross flow filtration of alcohol and water,
then that is distilled to remove alcohol
How fining agent works?
Fining agent must have opposite charge from wine colloid. The fining agent and colloid attract each other and form a solid large enough to be removed by racking or filtration.
Diatomaceous earth also known as?
Kaiselguhr
Depth filtration types lof filters?
Diatomaceous earth
Sheet filters
Free SO2 meaning? Which one effective SO2?
When SO2 added - it dissolves and some reacts.
This proportion called “bound SO2” - ineffective
“free SO2” - not bound
Free SO2 exists in relatively inactive form and a small proportion exists as molecular SO2 - which is most effective against oxidation and microbes.
Most effective one - molecular SO2 (which exist in free SO2)
When pH low - higher free SO2 - much effective
high pH - add more SO2
What is sparging?
Process that removes oxygen from the wine before bottling.
why? oxygen in wine will reduce shelf life
What are management options for drought?
irrigation
drought resistant rootstock
drought tolerant variety (Garnacha)
What are techniques to clarify must or wine?
Sedimentation
Centrifugation
Clarifying agent
Filtration
What techniques for enrichment?
- Adding dry sugar - chaptalisation - most common
- Adding grape must
- RCGM
- Reverse osmosis
- Vacuum extraction
- Chilling- cryoeztraction
Techniques to reduce alcohol
- Adding water
- Reverse osmosis
- Spinning cone
Acidification?
- Citric acid
- Tartaric acid - most common
- Malic acid
- Lactic acid
Deacidification?
- Calcium carbonate
- Potassium carbonate
- Ion exchange
what is stomata?
Stomata are pores on the underside of leaves that allow a plant to take in carbon dioxide, which is needed for photosynthesis;
They also allow water vapor to diffuse out of the plant, but when conditions are hot or dry they can close to reduce water loss, but limits photosynthesis by preventing carbon dioxide from entering the vine.
What is inflorescence?
A cluster of flowers on a stem which, when fertilized, develops into a bunch of grapes at fruit set.
What is a cutting?
A section of a vine shoot that is planted which then grows as a new plant.
What is layering and how is it done?
The shoot is bent down and a section of it is buried in the ground with the tip of it pointing up out of the ground. The buried part of the shoot takes root. Once the new roots are established, the cane linking the new growth to the original plant is cut.
The new vine now grows on its own roots, not those of a rootstock, which can be problematic in that the new roots don’t offer any kind of resistance to phylloxera.
What is clonal selection?
When vine nurseries or grape growers propagate a vine that has somewhat different but desirable characteristics, or mutations, by using cuttings from that vine to grow new vines which will then have the same desirable and somewhat different characteristics (mutations).
What is Mass Selection (also known as Sélection Massale)?
technique that vineyard owners take cutting from their vines and cultivate these cuttings (generally from best performing vines). These cutting can be sent to nursery for grafting onto rootstocks.
Advantages - increase diversity,
using own planting material
Disadvantages - costly if you are big wineries, grape grower may not be aware that vine is virus effected.
Potassium is important for?
help regulate flow of water.
very high level of potassium - problem to uptake magnesium
low level - low sugar accumulation in the grapes->reduce yield
NItrogen is important for?
Impact vine vigour and grape quality. Its a component of protein and chlorophil.
too much nitrogen in the soil - excess vegetative growth
too little nitrogen - yellowing vine leave->reduce yields
grapes low nitrogen ->problematic for fermentation
Phosphorus is important for?
for photosynthesis
low phosphorus - diminish (weak) water take up and nutrients
magnesium is important for?
found in chlorophil and important for photosynthesis
low magnesium - poor ripening
calcium is important for?
in the structure of plant cell and photosynthesis
low calcium - negative influence on fruit set
2 types of frosts?
- advective frost (cold air from cold area)
- radiative frost (cold air will collect at valley bottom because heat will lost on still, cool nights, freezing cold air will develop)
what are management options for excess of water?
plant on slope
free draining soil
construction of drainage system
what are management options for untimely rainfall?
nothing can be done:
choice of site - slopes
soil
drainage
monitoring the forecast - early harvest with less-ripe fruits or risk to lose
what are management options for freeze?
hillside sides
vineyards near large bodies of water
vineyards must be planted where snow is most thick
Cab.F, Riesling choice or Concord
reactive:
- build up soil around the graft, bury vines - expensive
-vines can be pruned to have several trunks, so that killed in winter can be replaced.
what are management options for frost?
how to reduce risk:
1. avoid frost pockets
2. delaying pruning
3. type of grape variety (late budding)
4. training high off the ground
5. bare soil between the rows (cover crops increase risk of frost)
how to combat:
1. water sprinklers
2. wind machines (helicopters)
3. smudge pots
what are management options for hail?
- rockets - silver iodide - cause rainfall than hail
- netting (Mendoza)
- strategic planning (different vineyards in different areas Burgundy)
- insurance against hail - expensive
what are management options for sunburn?
- Canopy managememnt
- Row orientation - avoid from east to west (avoid hottest aspects) better north-south orientation.
- if heatwave is forecast - additional irrigation (avoid water stress)
- sunscreen spray and shading with cloth or net
what are management options for fire?
- employee training
- install fire detectors and sprinklers
- install and maintain water tanks
what are management options for smoke taint?
- micro-vinification (make an analysis) make sample
- hand-harvest, gentle and whole bunch pressing (to get more fruitiness), fermentation in low temperatures, shorter/less maceration (all to increase fruitiness)
- flash-detente or reverse osmosis
- can blend with unaffected wines
6 pests types?
- phylloxera
- mammals
- birds
- spider mites
- grape moths
6.nematodes
6 fungal diseases?
- powdery mildew
- downy mildew
- esca
- grey rot
- eutypa dieback
- phomopsis cane and leaf spot
2 types of bacterial diseases?
- Pierce’s disease
- Grapevine yellows
2 types of viruses?
- Fanleaf virus
- Leafroll virus
What is vector?
is an organism that transmit a disease (sharpshooter - Pierce’s Disease and leafhopper - grapevine yellows)
6 aims of canopy management?
- Maximise the effectivenesss of light interception
- Reduce the shade within the canopy
- Ensure that microclimate is as uniform as possible so that grapes ripen evenly
- balance between vegetative and reproductive functions of the vine
- ease mechanisation and/or manual labour
- air circulation to reduce incidence of disease
What is green harvest?
or “crop thinning”, Its when you harvest grape bunches during summer time to increase ripiness of those bunches that left on the vine. It can enhance ripening process and improve unformity of ripiness.
Mist, fog and cloud influence?
Sonoma, Napa, Leyda Valley, Sauternes
limited sunlight ->reduce photosynthesys ->slow down sugar accumulation and acid degradation. (beneficial in warm climate for early ripening grapes)
Mist & fog - increased humid ->fungal disease,
if sunny and warm afternoon ->noble rot (Sauternes)
Characteristics of the soil for effect on temperature?
- Drainage - sandy, stony - warm up quickly (desirable in cool climate - budburst - but frost risk)
- Colour
light color (chalk Sancerre) - extra solar radiation
dark color (volcanic soil Etna) - absorb energy and re-radiate at night (beneficial in cool climate)
stony soil - absorb heat and release at night
Winds effect on the temperature?
- warming or cooling t
- pretect from disease
- increase evapotranspiration rate
- damage vines and vineyard trellising
Proximity to water effect on t?
- temperature
- protect from frost
- coastal area - moderate t (Bordeaux, Oregon)
- Radiation reflected from water surface (depend on angle, high altitude increase angle)
- El Nino and La Nina (weather affect on Pacific)
El Nino
Washington & Oregon, Australia - dry and warm t (AUS drought)
South America & California - high rainfall, warm t (hurricaine)
La Nina
Washington & Oregon, Australia - cool t , wet
South America & California - warm t, dry
angle of solar radiation?
angle at equator 90* = more heat
far from equator - lower angle (low angle = less heat)
low angle - high latitude
slopes - increase angle -> increase heat
slopes beneficial at cool climates
4 stages of grape development?
- Early grape growth
- Veraison
- Ripening
- Extra ripening
Early grape growth stage?
- green grapes grow in size
- tartaric and malic acid accumulate
- aroma compounds and precursors develop
- tannins accumulate
- sugar is low - best for this period mild water stress
Veraison stage ?
- grape growth slow down
- grapes cells - stretchy and subtle
- color change (black grape become red)
Ripening stage?
level of sugar - key parameter of ripening
1. acid - malic down->total acid down
2. methoxypyrazine down, other aroma up
3. tannin - start to decrease and polimerize
4. anthocyanin up
extra ripening stage?
- grapes shrivel
- no more sugar or water imported to grape
- water loss through transpiration (sugar concentration)
- extra ripe aroma develop
Diurnal range in regions with near water and high altitude?
in continental or high altitude - high DR
regions near body of water - low DR
High DR favorable in which regions?
in warm, hot climate
Mendoza or Ribera del Duero - slow down acid lost and beneficial for formation of anthicyanins and aroma retention - rotundone
low DR beneficial for which regions?
in cool, moderate climate
Mornington Peninsula or Mosel
allo ripening (even at night)
breakdown methoxypyrazine
Too much or too less water affect on during ripening period?
- too much - dilution & grape spitting (botrytis)
- too less - grape shrivel and reduce desired level of ripiness
Vine need water to survive how much?
500 mm in cool climate
750 mm in warm climate
What are organic nutrients for soil?
Manure or compost (that they have to break down by worms, bacteria to be available for vine take nutrients - called mineralisation)
What is mineralisation?
Organic turn to inorganic by help with worms or bacteria or fungi.
Manure or compost (that they have to break down by worms, bacteria to be available for vine take nutrients - called mineralisation)
Chlorosis is what?
High pH soil
(limestone soil or high calcium carbonate) - vine not able to take iron -> leaves turn yellow - chlorosis
How natural factor make nutrients available for vine?
- soil pH (high soil pH - chlorosis)
- soil health - if earthworms, bacteria and fungi - can convert compost or manure into available nutrient to the vine
- soil texture (high clay - holding capacity up, sandy soil down, but humus can increase capasity of holding)
- soil topography (slopes down, plains, valley floor - high fertile)
How to improve nutrients in the soil
Normally vine need low nutrients - so many soil is suitable for vine,
but can improve by:
1. adding compost
2. fertilisers
3. cover crop
4. mulching
(see again managing nutrients and water chapter 6)
4 types of classifying climate ?
- GDD - (Winkler) - (av t - 10)(Apr-Oct)+summ all
- Hunglin Index - similar GDD, but take into account mean&max t, daylength in high latitude
- MJT - mean Jan/Jul t + himudity, continentality, hours of sunshine
- GST - mean t of growing season
What is mean continentality?
is a measure of difference annual t of hottest and coldest month.
Large bodies of water, ocean, sea, large lake - moderating affect winter t and summer t
Coastal - low continentality -> maritime or mediterranean
Regions far inland from ocean - continental
Conventional viticulture aims?
Increase production and reduce labour
Conventional viticulture use of?
- mechanisation
- chemical inputs (herbicides, disease, pest agrochemicals, fertilisers etc)
- irrigartion
- clonal selection
what is lutte resonée?
Integrated Pest Management - is a key part in sustainable viticulture
economic threshold meaning in sustainable viticulture?
when level of damage exceed the cost of intervention
Lutte Raisonee what can do?
IPM - build on on some organic insights but can use chemicals,
IPM will give detailed instruction to grape grower how to identify and monitor pests or disease and will tell limit when can use chemical.
He will tell also how to set preventative measures
they also seek - first to boost grape own defence system
Plus and minus of Sustainable viticulture?
+
1. more thoughful approach
2. use scientific understanding
3. reduction in spraying
4. cost saving
-
1. not protected
2. can be too low standards (ex NZ)
What is Bordeaux mixture and when use?
Copper sulfate with lime (use for downy mildew) . protection of these mildew only last until 20 mm of rain has fallen.
Organic viticulture aim and DONT’s?
aim :
1. improve soil
2. range of micorbes & animals
within both increase health of vine and disease resistant
Reject:
1. synthetic fertilisers
2. herbicides
3. pesticides
4. fundicides
Instead use:
synthetic fertilisers - natural fertiliser which is animal manure, natural calcium carbonate, compost
pesticides - cover crop
pesticides - natural predators, bacteria bacillus subtillus, sexual confusion
fungicides - bordeaux mixture, sulfur and copper culfate
The key features of Organic Viticulture?
- Compost - nutrient for vine, improve structure of soil, increase biomass
- Natural fertilisers - animal manure, natural calcium carbonate - the idea is restore balance of the vineyard
- cover crop - cultivation of it improve of life in the soil (green manure)
- reduction of monoculture - cover crop, planting hedges, biodiversity
The key features of Biodynamic Viticulture?
- Builds upon organic
- The vineyard soil is seen as part of a connected system with the planet Earth, the air and other planets.
- Practitioners adapt their grape growing practices to coincide with the cycles of the planets, moon and stars.
- Special biodynamic preparations are used to treat the vines.
What are ‘preparations’?
- Homeopathic remedies based on natural treatments
- Used to fertilise the soil, treat diseases and ward off pests
What is Preparation 500?
horn manure
- Cow manure stuffed into cow’s horn
- Burying horn in the soil throughout the winter
- Later dug up and the contents are dynamised (stirring the contents of the horn into water)
- Sprayed onto the soil as a homeopathic compost
Goal: manure is believed to catalyse humus formation
What is Preparation 501?
A treatment based on silica
- Fill a cow’s horn with ground quartz (silica)
- Bury it for six months
- Then dug up, dynamised and sprayed onto the soil
- Goal: silica is thought to encourage plant growth
What are Preparations 502-507?
- Belief: compost has to be first ‘activated’ by a series of starters added in tiny quantities
- Starters: yarrow, chamomile, nettle, oak bark, dandelion or valerian prepared in various ways; for example, the yarrow in a deer’s bladder
- Goal: assist with the decomposition of the compost.
What is precision viticulture (PV)?
- A branch of precision agriculture.
- Utilises data from the vineyard (soil, vine vigour, topography, plant growth).
- Responds to variations from plot to plot and row to row.
PV what is difference than traditional viticulture?
- Targeted interventions based on collected data.
- Precise actions for pruning, leaf removal, treatments, irrigation, crop thinning, and harvesting.
Examples of changes made based on the collected data for PV:
- Changing rootstock based on soil fertility.
- Increasing leaf-stripping in areas with high vine vigour.
What are the objectives of precision viticulture?
- Responding to variations in the vineyard.
- Producing best quality and yield.
- Reducing environmental impact.
- Lowering treatment costs.
How can precision viticulture be used to benefit vineyards?
It can be used to identify different quality zones and to tailor a wide range of interventions (choice of variety and rootstock, canopy management, treatments, harvest dates) with the aim of improving yields and/or quality.
(What?) (How?) (Why?) (So?) (and then?/but?)
What is humus?
Depending on the questions and how much are you required to expand the answer, I find structuring the answer by asking myself these questions helps me, you can find one that works for you too:
(What?) (How?) (Why?) (So?) (and then?/but?)
(What) Humus is organic matter in the soil that is formed by the partial decomposition of plant and animal material by soil microbes and earthworms. It has a spongey texture, large surface area and is able to adsorb water and nutrients.
(How?) It helps to bind soils together and can help soils to retain water and nutrients.
(Why?) This is particularly important in vineyard where water is a limiting factor. It also increases the available nutrients that the vine needs to grow successfully.
(So?) Summary, i.e., ensuring soil is well prepared.
(And then?/but?) type of managing soil in organic and biodynamic viticulture
Define Conventional Winemaking practice and 3 techniques?
Builds on scientific understanding of fermentation processes.
3 techniques:
1. Temperature Control
2. Use of additives and/or processing aids
3.Manipulations
Based on Louis Pasteur’s work in 1860s identifying bacteria and yeasts.
Aim of conventional winemaking?
To produce stable wines which reliably show fruit character and have no faults.
Define Organic Winemaking?
- made with organically grown grapes
- complies with rules that restrict certain practices from being performed during winemaking.
Define Biodynamic Winemaking?
- Biodynamically certified grapes.
- Certain winemaking practices are required or encouraged by the certifying body, Demeter. Local Demeter certifiers determine locally specific requirements.
What is not allowed in biodynamic winemaking?
- increasing alcohol levels by concentrating the must
- addition of tannins and certain fining agents (e.g. isinglass)
Define natural winemaking?
- approach to winemaking where nothing is added and nothing removed.
- But it is accepted that it refers to a wine that is made with the fewest possible manipulations.
What is allowed to use in Organic Winemaking?
Many conventional methods are allowed,
but Ecocert will give list of excluded processes, example partial de-alcoholisation.
What is allowed to use in Biodynamic Winemaking in UK and USA?
UK - natural yeast, but organic or commercial yeast can be used
ban - alcohol level increase by concentration entire must
USA - natural yeast, but certain commercial yeast can use if stuck fermentation (case by case basis)
many products are not permitted - adding tannin, certain fining agent - isinglass)
Vineyard establishment requirements (the most important)?
- site
-soil
-planting material
What is soil texture and structure?
- Texture - proportion of mineral particles: sand, silt and clay
clay - fine texture.. - Structure -
high clay - sticky - challenging for root penetriate and challenging for soil cultivation
high sand - (or gravel, pebbles) - loosely structured, need more clay to bind them
What is subsoiling?
process that break down plough pan (hard surface) which may have formed after years and years.
High pH in soil meaning?
Limestone soil
cant get enough iron = chlorosis
low pH in soil meaning?
Acidic soil
Struggle to take phosphorus
Pest tolerant rootstocks? (root-knot nematodes)
Ramsey and Dog Ridge (Vitis Champini)
Water stress/drought tolerant rootstocks?
110R, 140 R - drought tolerant (V.Rupestris and V.Berlandieri)
110R - tolerant to acidic soil
140 R - high vigour
- 140 R can use if need sparkling wine production (where need high yeald with delicate aromas than lower yeald with concentrated aromas) or
can boost vigour in unfertile soil and dry conditions.
Rootstock that tolerant to waterlogged soil?
Riparia Gloire (Vitis Riparia) - useful in high rainfall and water-retaining soil
water and salt tolerant rootstock?
1103P
Low pH soil (acidic soil) tolerant rootstock?
99R and 110R
High pH soil (acidic soil) tolerant rootstock?
high lime content (limestone) - 41B
low vigour rootstock?
420A and 3309C
high vigour rootstock?
140R
Site selection for high-volume inexpensive or mid-priced wines?
Aim - cheap and consistent high yield
A flat, fertile in a warm, dry climate
Flat, fertile, warm - high vigour+irrigation
Dry - less disease (save money on fungicide and less sorting)
flat - machinery
Site selection for premium or super premium wines?
Aim - healthy grapes of the optimum composition (acid, tannin, aroma, sugar, colour)
cool climate - sites that maximise potential to ripen grapes ->aspects (Rheingau, Germany)
Warm climate - cool sites ->high altitude (Lujan de Cuyo, Mendoza, Argentina)
->cooling sea breezes (Casablanca, Chile)
Plus consider logistical, legal and cost factors (6)
consider logistical, legal and cost factors (6) when choosing the site?
- cost of land
- location, layout, topography
- steep slopes
- easy access to vineyard and distance to winery (to transfer)
- proximity of the vineyard and winery (for guests, customers)
- irrigation
Ensure soil is suitable for growing grapes 3 factors?
- Drainage and structure
- Mineral composition
- Presence of pests or unwanted plants
4 main effect of soil structure?
- root penetriation
- water drainage
- nutrient holding capacity
- workability
5 main soil practices that may need to occur before planting vines?
- remove large rocks
- subsoiling - breaking down a plough pan
- removing old roots
- applying herbicides to treat weeds
- applying manure, compost, fertilisers to increase nutrients
What does ploughing effect to the soil?
turn over the surface layer of the soil, burying it
done to incorporate manure, compost or fertilisers into soil better
Name 6 characteristics when selecting a grape variety to plant?
- Time of budding (Char or Riesling)
- Duration of annual life-cycle (PN or Grenache)
- tolerance to drought (Grenache)
- resitance to disease (CabS, Merlot)
- winter hardiness (Riesling, Vidal)
- vigour (SBL)
6 other factors to take into account when selecting grape variety?
- style of wine (low tannin, fruity)
- yeald (inexpensive)
- cost (PN - very costly)
- law (Proscco-glera)
- availability (sold out)
- market demand (fashion grape)
4 factors to consider when selecting rootstocks?
- pest
- water
- soil pH
- Vigour
First 2-3 years of vine what grape grower do?
remove inflorescence
- allowing young vine to concentrate its resources on growth
between which age vines produce their highest yield?
between 10-40 years
3 theories behind the idea that old vines make good wine?
- better balanced and adapted to environment
- lower yield and higher concentration
- more old wood meaning higher stores carbohydrates when stressed
How to control nutrient management?
- Applying fertilisers
- Promotion of biological activity and soil structure, and management of weed
Managing the soil health?
soil health =:
1. structure of the soil
2. amount of organic matter and humus (organic matter =nutrients)
3. number of living organisms (they need to break down)
4. available nutrients (nitrogen, potassium, phosphorus - essential for photosynthesis or to grow successfully)
5 methods of weed management?
- Cultivation
- Herbicides
- animal grazing
- Cover crop
- Mulching
3 types of herbicides?
- Pre-emergence herbicides - sprayed before weed established, absorbed by roots = inhibits germination
- Contact herbicides - sprayed on established weed and kill green part = death of plant
- Systemic herbicides - spread on established weed, taken by leaves and go travel down = kill whole plant
Disadvantage of herbcides?
- risk of poison operator, consumer, environment
- weed can be resistant, then need large amount
- can increase vine vigour too much as no competition for water and nutrients
- they are not allowed in biodynamic and organic viti
Cover crops need for what?
Cover crops - specifically planted to have beneficial effect on the vineyard.
1. Suppress weed (stop growing weed)
2. improve soil structure
3. compete with water and nutrients in fertile soils
4. manage soil erosion
5. enhance biodiversity
6. provide surface to drive on
Examples of cover crops?
Legume: beans and clover
Cereal: ryegrass and oat
Also possible to leave - natural vegetation
Do you need Cover Crop management?
Yes
Especially at key times in the vine cycle, so that CC wont compete for nutrients and water.
What is Cover crop management?
Ploughing into the soil -> which also provide organic matter and this way fertilise the soil. (called green manure)
Mulching is what?
is spreading of matter onto the soil to suppress the growth of weed, and it can provide nutrient and humus -> which promote biological activity and good soil structure.
its made of biodegradable natural materials such as straw or bark chips.
Advantages and disadvantages of mulching?
Advantages:
1. doesnt use any chemical (ok in organic and biodynamic)
2. reduce water evaporation (good in dry climate)
3. can be sourse of humus and nutrients ->improve soil structure
Disadvantage:
1, bulky - expensive to transport and spread
2. only effective if applied thick layer
3. it can increase vigour too much as there no competition for water and nutrients
What are water management?
- Irrigation
- Water drainage
how else promote root go deep into soil?
- cultivation (one of option)
Define regulated deficit irrigation (RDI).
A system of timed and regulated irrigation application to apply mild to moderate stress to the vine at a specified time within the growing season.
When is RDI typically applied?
Between fruit set and veraison to limit shoot growth and favour grape development.
Three benefits of RDI.
- Vine growth and grape development are controlled
- Less water is required
- Improvement to grape quality
Define dry farming.
Not using irrigation in areas with limited rainfall
Leads to lower yields with potentially an improvement in grape quality.
Three ways to regulate water in regions with high rainfall in the growing season.
Artificial drainage systems in the vineyard.
Leaving natural vegetation or planting cover crops to compete with vines for water.
Improving the soil structure to better regulate water drainage
Describe the use of fertilisers.
Two types - Organic and mineral
They can be added before planting to help the growth of young vines.
They can be applied to established vineyards to correct nutrient deficiencies.
Advantages of organic fertilisers?
Cheap or even free
Can be good for soil structure and water retention
Provide nutrition for soil organisms and promote living matter in the soil
What are mineral fertilisers?
Fertiliser that is extracted from the ground or chemically manufactured.
Advantages of mineral fertilisers?
- Can be tailored to suit the nutrient requirements of the vineyard
- Inorganic form can be readily available to the vines
- More concentrated, cheaper to transport and easier to distribute
What is cultivation?
A method of weed control that involves ploughing the soil to cut or disturb the weeds’ root systems.
What are the advantages of cultivation?
Does not use any chemicals,
can be used in organic and biodynamic viticulture.
It enables fertiliser and mown cover crops to be incorporated into the soil at the same time as removing weeds.
Name six reasons why might cover crops might be used.
- Grown to suppress weeds
- Planted to improve soil structure
- Compete with the vine for nutrient and water availability in fertile sites
- Manage soil erosion
- Enhance biodiversity
- Provide a stable surface to drive vineyard machinery on
What is green manure?
Cover crops of vegetation that are ploughed into the soil
Define mulching
The spreading of matter onto the vineyard soil to suppress the growth of weeds.
Name 8 weather hazards?
- Drought
- Excess of water
- untimely rainfall
- freeze
- frost
- hail
- sunburn
- smoke taint
Solution for drought?
- Irrigation system
- drought resistant rootstock
- drought tolerant grape
What is canopy management?
organisations of the shoots, leaves and fruit of the vine in order to maximise grape yield and quality.
Purpose of maximising leaf surface area exposed to sunlight.
- Increases the vine’s photosynthetic capacity (compared to a vine with a dense, shaded canopy)
- Increases the vine’s ability to ripen larger yields
Problems associated with dense canopies.
Poor air circulation
Higher humidity within the canopy
Suitable conditions for fungal diseases to develop
Fungicides will have less penetration into the canopy
Seven effects of good canopy management on grape quality due to increased exposure to sun and heat.
- Increased sugar levels
- Increased tannin levels and riper tannins in grape skins
- Enhanced colour in black grape skins
- Decreased malic acid
- Increased levels of favourable aroma precursors
- Decreased methoxypyrazines
- Reduction of fungal disease pressure
Five factors that determine the ideal amount of fruit.
- Climate
- Water and nutrients
- Grape variety
- Choice of rootstock
- Desired wine style
At what stage of the annual vineyard activities can the number of shoots on a vine be controlled?
Winter pruning
Summer pruning
5 main canopy management techniques are:
- vine training
- vine trellising
- winter pruning
- summer pruning
- overall plant vigour management
What vineyard operations are performed during Summer Pruning?
-disbudding
- shoot removal
- shoot positioning
- pinching
- shoot trimming
- leaf removal
- crop thinning/green harvesting
When establishing a vineyard choice of vine training and trellising depends on?
density
How is the optimum vine density determined?
- the vigour of the vine (which in turn is influenced by natural resources and planting materials)
- the type of trellising system used
- what access requirements between the vines
How to choose row orientation?
Depends on climatic and logistic conditions:
1. North-South - most sunlight, however west - more shade (from sunburn - afternoon sun)
2. winds - 90* to the wind - most protected
3. slopes - if angle more than 10* - plant up to down
4. row parallel to longest side of vineyard
What is vine training?
Typically refers to the shape of the permanent wood of the vine.
Two main categories of vine training?
- head training
- cordon training
Describe low-training and high training of a vine.
Low:
- The vine trunk is short
- Benefit from heat retained by the soil
- Provide greater protection from wind
High:
- The vine trunk is long
- Better avoid frosts
- Make manual interventions (e.g. harvesting) easier
Two main types of winter pruning.
- Spur pruning
- Replacement cane pruning
Difference in ease of spur or replacement cane pruning?
- Spur pruning is easier to carry out and can often be mechanised.
- Replacement cane pruning is more complex and requires skill to pick suitable canes and train them.
Climate where bush vines are popular and why?
Hot and sunny regions
Dry conditions
The shade created is beneficial to avoid sunburn
Dry conditions inhibit disease in a potentially humid fruiting zone
Three advantages of trellised training systems?
- Maximise light interception
- Increase air flow through the canopy (reducing risk of fungal disease)
- Aids mechanisation, by positioning the fruit in one area
Three aims of summer pruning.
- Enhancing grape ripening
- Reducing chance of fungal disease
- Making the vineyard easier to manage.
Describe disbudding.
AKA debudding
- Removal of excess buds
Goals:
1. manage vine balance and yields (quality, law)
2. to remove buds that are poorly positioned (downward facing, close together)
3. remove buds of non-fruit bearing shoots (competition)
Describe shoot removal.
- Removal of shoots, often laterals, that are infertile or poorly positioned (e.g. too close together or low down on the trunk)
- Help to maintain a well-organised, open canopy.
Describe pinching.
- Removes the shoot tips at flowering
- Improve fruit set.
Describe shoot trimming.
- Cutting shoots to limit growth and reduce canopy thickness
- Enhances fruit ripening by reducing competition for carbohydrates between the shoot tips and fruit
- Lowers disease pressure through better air circulation and improved spray penetration.
Describe leaf stripping.
- Removing leaves
- Reduce shading of fruit and hence enhance ripening
- Lower disease pressure through better air circulation and improved spray penetration.
Where might leaf stripping be avoided?
In warm and hot climates, excessive removal of leaves can expose the grapes to too much sunshine and heat and lead to sunburn.
Describe crop thinning or green harvesting.
- Removal of bunches of grapes
- Increase ripeness of those grapes left on the vine.
Summer pruning techniques (7)?
- Debudding
- Shoot removal
- Shoot positioning
- Pinching
- Shoot trimming
- Leaf removal
- Green harvest
Summer pruning aim?
Enhance grape ripening
reduce chance of fungal disease
vineyard easier to manage
Why is potential alcohol for harvest less relevant today?
Warmer climate speeding up sugar development
Better viticulture enabling grapes to ripen more successfully
More focus on aroma and tannin development
Three ways ripeness is measured for harvest and how?
- Sugar - refarctometer
- Acid - titration or pH meter
- Aroma and Tannins ripiness - taste
What is high tech for harvest measure?
spectroscopy - multiple measures
Typical sugar level range for dry wine
19-25 Brix (equivalent of 11-15% ABV )
Importance of harvest date for wines that have residual sugar?
- Some harvested late to concentrate the sugars in the grapes
- Some need hand-harvesting over several passes through the vineyard to select the most botrytised grapes at that time
- Some grapes can only be picked when temperatures reach below certain levels (Icewine, Eiswein)
What steps taken to improve the quality of machine-harvested wine?
- select out undesireble grapes before machine
- use bow-rod shaking machine
- use latest machine with optical sorting, crushing and adding SO2
- rigorous sorting on arrival at the winery
Growers can choice date of harvest depend which style of wines?
- Chenin Blanc , Loire - early for sparkling, mid - dry and off-dry wine, later - botrytis or late harvest styles
- Zinfandel, California - white zinfandel early, september - red wine
- wines with RS - botrytis many passing or icewine only when -8* canada
- Contuniuing debate over “hang time” - consumer likes, but grower think its unbalanced
What are 4 main advantages of machine-harvesting?
- faster and cheaper
- Avoids issues of the lack of availability/unreliability of workers
- Grapes can be harvested at night and be kept up to 15°C cooler
- The timing of the harvest can wait and then carried out quickly
What are the benefits of harvesting at night?
- Can reduce microbial spoilage and oxidation
- For white, fruity wines, starting the winemaking with cool fruit preserves the intensity of fruit aromas.
- Saves costs on refrigeration
What are five scenarios when hand-harvesting is required?
- Whole bunches - premium sparkling wine (Champagne and other bottle fermented Sp.W)
- Carbonic or semi-carbonic wine method - Beaujolais or other wine
- Required selective garvesting (botrytis Trockenbeereslause Mosel)
- Steep slopes or uneven land (Duoro Valley)
- Bush vines (machine require trellis)
What are the main components of wine? (7)
- Water
- Alcohol
- Acids
- Wine aromatics
- Residual sugar
- Glycerol
- Phenolics
Low pH gives what?
Increase microbiological stability
increase effectiveness of So2
gives to red wines - bright red colour
and enhance ability to age well
What types of acids can be formed during the winemaking processes?
Lactic
Acetic
Which fault does acetic acid contribute to?
volatile acidity
What is the typical range of Total Acidity in wines.
5.5-8.5 g/L
What are the four sources of aromatics in wine?
Aromas from the grapes
Aromas created by fermentation due to the presence of aroma precursors in the grape must
Aromas originating from Fermentation and its by-products
Aromas from other sources
Aromas from grape?
Aromas from precursors?
Aroma from fermentation and by-product?
Aroma from other sources?
- Methoxypyrazine, rotundone
- Thiols , terpenes
- Esters, acetaldehyde, diacetyl, sulfur compounds
- vanilin, eucalyptol
Sorting grapes in french?
Triage
What are the options for sorting grapes for quality wines?
- Removal of unwanted grapes and bunches during or before hand picking
- Sorting by hand
- Optical sorting using a high tech digital imaging equipment.
What are yeast nutrients?
Diammonium phosphate (DAP)
thiamine (vitamin B1)
Minimise oxygen during winemaking options?
- avoid ullage
- use inert gases
- addition of SO2
- use impermeable containers
- cool constant t
positive effects from controlled oxygen during winemaking?
- oxygen required to start fermentation
- lack of enough 02 - reductive off flavours
- in wh wine - hyperoxidation - greater stability from O2
- in red wines - essential for reaction between anthocyanins and tannins
- in red wine - color stability
- also change aroma/flavors
Oxygen exposure can increase by?
- cap management
- use small wooden barrels
- increase number of racking and lees stirring
- allow ullage
- hyperoxidation or microoxidation
What is Micro-oxygenation?
is a technique that provide cheaper alternative to oak ageing. It involves bubbling oxygen through wine.
Stainless steel tank
After AF
What is SO2?
Ia a preservative:
1. Anti-oxydant
2. Anti-microbial
How to reduce SO2?
- winery hygiene, effective sorting - limit microbes
- limit O2 exposure & keep grapes in cool t
Grape reception 4 stages?
- Chilling
- Sorting
- Destemming
- Crushing
Chilling and sorting , what steps?
1.Chilling either:
refrigerator or heat exchanger
2. Sorting
Cheap wines - no need sorting
Mid price and premium - sorting:
a. remove unwanted bunches (grapes) before picking or during pick (hand harv)
b. Sorting by hand on the table or vibrating table
c. Optical sorting
Sorting depends - ripiness and health
Not destemmed grapes used?
- red wine that use dome whole bunches (PN Burgundy)
- carbonic maceration (Beaujolais)
- Whole bunch pressing (Champagne)
Types of press?
- Pneumatic press (batch)
- Basket press (batch)
- Horizontal screw press (batch)
- Continous press
- modern press, computerized
5 must adjustments?
- Enrichment
- Reduce alcohol
- Acidification
- Deacidification
- Adding tannins
What yeast need ?
- Oxygen - to start
- need viable t
- yeast nutrients (especially nitrogen)
- absence of oxygen
Ambient yeast VS cultured yeast?
Ambient:
1. Add complexity
2. cost nothing
3. unique to a place
4. marketing
- : - start slowly and might VA, growth of spoilage organisms, take longer, not consistent
Cultured:
1. relaible
2. low level of VA, speed, clean
3. consistent
4. can choose what style
- : - similar, cost
T for fermentation
Cool 12-16*
Mid 17-25*
Warm 26-32*
Options for fermentation vessel?
- Stainless steel
- Concrete
- Wood
- Plastic vessel
- Terracotta
Ensure MLF will not happen?
- enzyme lysozyme (kill lactic bacteria)
- move batch away to other room- so wont spread bacteria
- filter out lactic acid bacteria
Conditions inhibit MLF?
- t<15
- low pH
- moderate level So2
Conditions that MLF will happen?
- 18-22*
- moderate pH 3.3 - 3.5
- low total SO2
How does spinning cone work and what is the drawback?
Spinning cone extracts aroma compounds. Then removes alcohol. Aroma compounds are blended back into the wine.
Drawback - expensive
How does reverse osmosis work and what are the drawbacks?
A form of cross flow filtration removing flavourless components (water and alcohol mixture). The alcohol is distilled from the mixture. The water is added back in to the original wine.
Drawback - Expensive
Why humidity is important during maturation?
any wine lost during maturation (evaporation)
when dry (low humidity) more water loss then alcohol and faster
this concentrate alcohol level in wine bring unbalanced wine - not desirable (and loss of wine - as need to top up more frequesntly)
thats why need humid condition.
Lees ageing has 5 effects on wine?
- Autolysis (flavor, body, texture)
- For white wine - stabilise unstable proteins
- Protect from oxygen
- Produce reductive sulfur compounds (if layer is too thick) - small amount xomplexity
- Nutrients for microbes
Oxydation reactions in Maturation and speed depends?
- Reduction of primary aroma & development of tertiary aromas
- Reduce color of wine
- Softening tannins
Speed - amount of oxygen and temperature
Micro-oxygenation advantage?
Quicker than barrel
rate of O2 can control
can use with oak chips
Role of wood in maturation depend?
- Age of vessel
- Size of vessel
- Type of wood
- Production of vessel (seasoned, toasted)
- lenght of time in wood
What is bentonite?
A form of clay, that adsorbs unstable proteins and unstable collodial colouring matter.
What is DMDC (Velcorin)?
Inactivates bretts
(microbiological stability or faults of wine)
Define
Describe
Comment
Comprehension
Explain
define - what is it
describe - To state facts and give details on a given subject.
Examples may also be required.
Comment - define+describe + cost etc include everything
Explain - how and why, here you give like cold t will will reduce rate of oxidation->as a result primary fruit etc using words like because
Define stabilisaion?
Stabilisation refer to several winemaking interventions which if not carried , could lead to to undesired effects in the finished wine, including unwanted haze, deposit in the bottle and rapid colour change.
3 types of stabilisation (techniques)
Protein (fining with bentonite)
Tartrate
Microbiological
Name tartrate stabilisation techniques.
Cold stabilisation
Contact Process
Electrodialysis
Ion exchange
CMC
Metatartaric acid
explain Cold stabilisation?
Tartrate stabilisation
wine -4* for 8 days
colloids must be removed by fining before otherwise they prevent forming of crystals
only removes potassium bitartrate
explain Contact Process?
Tartrate stabilisation
quicker reliable cheaper
wine chilled to 0*C for 1-2 hours
add potassium bitartrate ->speed up formation of crystals
explain Electrodialysis?
Tartrate stabilisation
this process uses charged membrane to remove selected ions
removes potassium and calcium ions
high investment, but total cost lower than cold stabilisation
explain Ion exchange?
Tartrate stabilisation
it doesnt remove tartrate but replace with hydrogen and sodium ions.
Some territories not allowed - as sodium is bad for health
explain CMC (carboxymethylcellulose)
Tartrate stabilisation
cellulose extracted from wood, it prevent tartrates from visible size.
Used widely for white wine (inexpensive)
dont use for red - as can reacts with tannins
explain Metatartaric acid?
Tartrate stabilisation
adding this compouns - prevent from growth of potassium tartrate or calcium tartrate.
Unstable and lost overtime, especially if stored in warm t
Quick and easy
Used for red wines, as for white wines CMC more effective
Post fermentation clarification techniques?
- sedimentation
- centrifugation
- fining
- filtration
High volume winery which method would use for clarification after fermentation?
Centrifugation - quick process that spins the wine at high speed to clarify it.
(it replace depth filtration also)
only high volume wineries (cost)
allow early bottling
Fining what he do?
Clarify wine
also solution for other problems:
- removal of harsh tannins
- browining in white wines
Fining agent must have opposite charge from wine colloid, so they attract each other and form large solid that precipitate and removed by racking or filtration.
Fining agent that removes unstable protein
Protein in red w no need to remove
Protein in white & rose wine - need remove ->haze
Bentonite - is a form of clay that absorbs unstable protein and unstable coloring matter (color loss in reds)
Fining agents that removes phenolics (colour and bitterness)
- Egg white - remove harsh tannins
- Gelatine (pork) - remove bitterness and astringency (ww browining)
- Casein (milk) - ww browing
- Isinglass (fish bladder) - bright appearance ww
- vegetable protein (potato and legume)
- PVPP (insoluble plastic) - ww browining & astringency (rarely used in red wine)
Fining agent that removese colour and off-odours
Charcoal - removes brown color and off odours (care need to take - easy over-fining)
2 types of filtration?
- Depth filtration (not absolute)
- Surface filtration (absolute)
Depth filtration
Non absolute (depth filtration)
1. Diatomaceous earth - DE - most common depth filtration, uses DE (kieselguhr) - pure silica
Can - thick and cloudy wine
desposed resposibly
Sheet filters
Non absolute (depth filtration)
uses sheets
investment, sheets - low price
membrane filters
absolute filter, surface filtration
mictobiological stability also done together (removed yeast and bacteria)
AKA cartridge filter
- slower than depth filter
-wine must be pre-filtered
- initially uses as final precaution before bottling ensure wine is mictobiologically stable
common form of filtration before bottling
Cross flow filters
Surface filter
Absolute filter
AKA tangential filters
can filter high load particles or lees very quickly
cartridge or earth disposed and buy new one
Machine - expensive
Suitable large wineries
Clarification must and wine, which only for must?
flotation - bubbling gas through must
fining agent : pectolitic enzymes
Microbiological stability how and what?
- Yeast - prevent from re-fermentation: (especially wines with RS)
sterile filtration
or
add sorbic acid and SO2 (inhibit yeast from growing) - Bacteria - exceptions of microbes can live in low pH and high alc:
a)Lactic acid bacteria - ensure MLF happened to prevent happening in the bottle
b) acetic acid bacteria
c) brettonomyces - filter or add DMDC (velcorin)
Wine faults?
- Cloudiness and hazes
- Tartrates
- Re-fermentation
- Cork taint
- Oxidation
- Volatile acidity
- Reduction
- Light strike
- Brettanomyces
Volatile acidity fault why and solutions?
excess amount give pungeant nail varnish
due to
- activity of acetic acid bacteria
- inadequate levels of SO2
- excess exposure to O2
Solution:
1. sorting and remove damage grapes
2. hygiene in the winery
3. keeping vessel top up
4. careful racking (to avoid O2)
5. maintain adequate SO2
define ideal wine closure?
- protect wine from rapid oxidation
- be inert
- be easy to remove & re-insert
- cheap, recyclable & free from faults
Define skin contact
is the process of leaving the juice in contact with the skins to extract compounds from skin. (similar to cold soaking in red winemaking)
Which style of wine would not carried out skin contact?
- For most of white - style - delicate fruity wines with minimum color and smooth mouthfeel
- If white wine style to be early drunk
- If grapes are under-ripe
- inexpensive white wines (as skin contact takes time, equipment and labour)
Skin contact most likely used in which grapes?
Skin contact maximise flavour extraction so most effectively used on aromatic grapes: Riesling, Gewurztraminer, Viognier, Muscat and SBl
What is orange wine?
Orange wine is made with white grapes and are fermented on the skins of the grapes.
Have characteristic of dried fruit, dried herbs, hay or nuts.
Skin contact how to carry out in which conditions?
Chilled below -15*
from 1 - 24 hour and over
chilling - give control, reduce rate of extraction, reduce threat from spoilage organisms, including likelihood sponatoeus fermentation
Define hyper-oxidation.
A technique of deliberately exposing the must to large quantities of oxygen before fermentation.
What does hyperoxidation do to the must and why is it performed on some wines?
It will oxidise compounds that oxidise readily.
These compounds turn brown the must.
It :
1. Stabilises the wine against oxidation
2. Removes bitter compounds that come from unripe skins, stems and seeds.
3. destroy VA compounds -> therefore used for neutral grapes
Temperature for white wine making?
12-16* - fruity
17-25 - if wine going through oak ageing
effects of MLF?
- reduction in acidity
- increase pH
- microbiological stability
- modification of the flavours of the wine
Aim of lees and impact for white wine (red wine not significant)?
Aim - give more body, soften the mouthfeel
and help to stabilise
- Protection from oxygen and may introduce some reductive sulfur compounds (which at low level - desirable struck match. smoke aromas)
What is called lees stirring?
Battonage
Key ways of producing wines with residual sugar?
- Concentrating the grape must (drying on the vine, drying off the vine, noble rot, freezing grapes on the vine)
- Stopping fermentation before dryness
- Blending in a sweetening component
What is lacasse?
enzyme that produced by noble rot (sweet wine making) that requires add more SO2, chilling and use of inert gases
What are the three main ways for producing wines with residual sugar?
- Concentrating grape must
- Stopping the fermentation before dryness
- Adding sweetening component
What factors affect the decision of how to make a sweet wine?
The style, quality and price of the wine that the winemaker wants to make.
The climate of the vineyard site
The local wine legislation.
How to stop the fermentation (for wine RS)?
- Cooling below 10*, adding SO2 and filter out yeast
- Fortification (adding alcohol to kill yeast) D5
For high volume inexpensive wines with RS which method use?
Stopping fermentation
Adding sweetening component (not allowed in some EU)
Factors that affect extractions are (for red winemaking)?
- Temperature - higher - greater extraction
- Time on skins - longer - greater or more mixed - greater extraction
- The medium in which the extraction is taking place – for example, tannins are most
soluble in alcoholic solutions (e.g. wine), whereas anthocyanins are most soluble in aqueous solutions (e.g. grape must).
How to have stability of colour?
The anthocyanins become more stable when they combine with tannins, resulting in greater colour stability.
Anthocyanin, tannins and oxygen.. ?reactions?
Anthocyanin is single molecule so its not stable by himself. So color can be lost during different winemaking techniques (lees ageing or adding SO2).
He need to bind together with tannin - to result colour stability.
Oxygen make easier - to make them together.
So processes like micro-oxygenation or barrel ageing - promote colour stability.
Over time anthocyanin-tannin compounds change in composition and become paler (when only anthocyanins - is faster)
Which winemaking steps can cause a loss of anthocyanins?
Lees ageing or adding SO2
What are the two categories of maceration prior to fermentation?
Cold maceration
Maceration using heat: Flash detente, thermovinifiction