Viticulture/Wine Making Flashcards
below about what temperature is the vine dormant
10C
3 ways temperature affects yield
1) vigour of the vines
2) number of flower clusters produced and their size
3) Success of the setting of these flowers into berries
3 ways temperature affects quality of crop
1) level of yield
2) accumulation of sugars/reduction of acids
3) development of wine aromas and their precursors
frost damage to vinifera at which temperature
starts at -15C, is serious at -20C, and fatal at -25C. Site usually unsuitable for viticulture if temp falls below -20C more than once every 20 years or if mean temp is below -1C during coldest month
Amerine and Winkler’s Heat Summation System measures Growing Degree Days (GDD)
subtract 10C from from mean temperature of the month and multiply result by number of days in month. Sums are totaled for each of the seven months of the growing season
EU zone A
Germany (excluding Baden), UK
min% abv - 5%
max enrichment +3.5% to 11.5% (to 12% for reds)
acid adjustment -1 - 0 g/L
EU zone B
Loire, Champagne, Alsace, Austria
min% abv - 6%
max enrichment +2.5% to 12% (12.5% for reds)
acid adjustment -1 - 0 g/L
EU zone C 1a
Bordeaux, SW France, Rhone, Vinho Verde
min% abv - 7.5%
max enrichment +2% to 12.5%
acid adjustment -1 - 0 g/L
EU zone C 1b
Hungary, Trentino-Alto Adige
min% abv - 8%
max enrichment +2% to 12.5%
acid adjustment -1 - 0 g/L
EU zone C 2
Languedoc-Roussillon, Provence, Northern Spain (except Atlantic Coast), Most of Italy
min% abv - 8.5%
max enrichment +2% to 13%
acid adjustment -1 - +2.5 g/L
EU zone C 3a
Parts of Greece
min% abv - 9%
max enrichment +2% to 13.5%
acid adjustment 0 - +2.5 g/L
EU zone C 3b
Portugal (except Vinho Verde), Southern Spain, Puglia, Sicily, Most of Greece
min% abv - 9%
max enrichment +2% to 13.5%
acid adjustment 0 - +2.5 g/L
How much water does vine need per growing season
500mm/year or equivalent in irrigation (cool climate)
as much as 750mm/year or equivalent in irrigation (hotter climates)
1mm of rainfall on one square meter
1 litre
affect of sunlight on vine growth
1) indirect effect due to heat accumulation
2) direct effect on bud viability, the initiation of vine flowers, berry ripening, cane maturation
3) direct effect on the rate of photosynthesis
Amount of sugar in grapes depends on
balance between amount of sugar created through photosynthesis (which increases with sunlight but not temperature) and the vine’s other metabolic needs (which increase with temperature)
mean temperature increase with elevation
0.6C with every 100 meter rise about sea level corresponding with a heat summation reduction of about 105 degree-days/year
particles in soil graded according to diameter (in mm)
0, clay, 0.002, silt, 0.02, fine sand, 0.2, sand, 2 gravel - 2+
loam
balanced mixture of clay, silt, and sand
limestone
sedimentary rock formed from deposition of shells and skeletons of marine animals. Consists of Calcium Carbonate is usually alkaline and free-draining
chalk
formed like limestone but has a lower density and is more free draining found in Champagne and Jerez
dolomite
similar to limestone but with high levels of magnesium
sandstone
made up of compressed sand (quartz)
shale
sedimentary rock originally composed of clay and is very soft
slate
shale that has been metamorphosised. ls harder and less porous than shale
granite
extremely hard and dense but still free draining
N
major constituent of cell proteins, nucleic acids, chlorophyll, and hormones. 2nd only to water in importance for plant growth
P
a key element in energy fixation. encourages root growth and ripening
K
regulates the flow of water and sugar in the plant which encourages ripening
Ca
regulates cell acidity and is an important component of cell walls
S
an essential constituent of some amino acids and enzymes
Mg
and essential component of chlorophyll, regulates internal acidity, sugar metabolism, encourages ripening
petiole
leaf stalk
floral initiation
embryonic flowers develop in the dormant bud the year preceding bud burst. success depends on temperature, sunlight exposure, and sufficient carbohydrate reserves in the wood
budburst
vines sensitive to late spring frosts at this stage
coulure
failure of berries to set or fertilize
layering
vine canes are buried in the ground then separated from the parent plant once established own roots. best way to propagate some species like v. berlandieri and rotundifolia
v. labrusca
found wild in NE USA. dark berries described as “foxy.” parent of american hybrids such as Concord.
v. riparia
found wild on river banks in Central-Eastern parts of North America. Surface rooting. Low in vigor. encourages early ripening. good resistance to phylloxera but suffers from chlorosis in chalky soils. sed to control vigor in highly fertile soils
chlorosis
iron deficiency
v. rupestris
found in southern center of USA. vigorous and deep rooting. susceptible to chlorosis. good choice of rootstock for poor soils with limited water availability.
v. berlandieri
grows on chalky slopes in southern USA and Mexico. vigorous and deep rooting. high resistance to chlorosis. poor ability to root so rarely used as a pure species. often hybridized with riparia and rupestris in order to produce lime-resistant rootstocks that graft and root easily with different levels of vigor
True/False. v. riparia is low in vigor
True
This rootstock is resistant to chlorosis
v. berlandieri
True/False. v. berlandieri has low vigor
False
True/False. v. riparia is drought resistant
False
True/False. v. rupestris is drought resistant
True
True/False. chardonnay is prone to Grey Rot
True
True/False. Chenin Blanc ripens unevenly
True. common to find leafy and tropical aromas in the same wine
True/False. Cabernet Sauvignon gives high yields despite low vigor.
True
Tempranillo can ripen with high levels of malic acid.
True. Therefore by-products of MLF are distinctive.
Pratylenchus and Meloidogyne
species of Nematode that cause damage by feeding off roots
Xiphinema Index
species of Nematode that spreads viral disease
true/false. v. riparia based rootstocks are drought resistant.
false. they are however able to tolerate damp conditions
v. rupestris will have _____ vigor
High
v. riparia will have _____ vigor
Low
True/False. Low vigor rootstocks are usually used in cooler climates.
True. They encourage earlier wine production and in quality wine production they can help control yield.
Riparia Gloire de Montpellier
very low vigor humid, cool, fertile soil Low lime tolerance Very low drought resistance Very high phylloxera tolerance nematode resistant Suitable for production of quality wines. Sensitive to compact soils. Prefers damp conditions.
Rupestris du Lot
Very high vigor deep, poor, healthy soils Low lime tolerance Drought resistant High phylloxera resistance Nematode resistant High vigor mediterranean rootstock. Sensitive to coulure and compact soils
AXR1
vinifera x rupestris. offers some of the lime tolerance of vinifera but shows inadequate phylloxera tolerance
High Vigor
suitable in many soil types
High lime tolerance
Moderate drought resistance
Very low phylloxera tolerance
Easy to graft, high yields of quality fruit, but phylloxera a major issue
3309 C (Couderc)
riparia x rupestris Moderate vigor Cool, fertile, permeable soils Low lime tolerance Very low drought resistance High phylloxera tolerance high nematode resistance Fruits well. Widely used in France, Germany, Switzerland. Particularly recommended for acid soils.
101-14 (Millardet et de Grasset)
riparia x rupestris Low vigor Deep, fertile, damp soil Low lime tolerance Very low drought resistance High phylloxera tolerance Moderate nematode resistance Suitable for production of quality wines
Schwarzman
riparia x rupestris Low vigor Deep, moist soil Low lime tolerance Very low drought resistance High phylloxera tolerance Very High nematode resistance Ideal for areas with serious nematode issues
riparia x rupestris
halfway between surface and deep rooting. average vigor. Good resistance to phylloxera but poor resistance to chlorosis
riparia x berlandieri
surface to semi-surface. Good rooting, high resistance to chlorosis. Good affinity with scions and resistance to phylloxera.
161 - 49C (Couderc)
riparia x berlandieri Low vigor cool, fertile, permeable soil High lime tolerance Very low drought resistance High phylloxera tolerance Low nematode resistance widely used in France, Germany, Switzerland. Good fruiting. Good for acid soils.
420A (Millardet et de Grasset)
riparia x berlandieri Low vigor cool, deep, rich, permeable Moderate lime tolerance Very low drought resistance Very high Phylloxera resistance Moderate nematode resistance Good for quality vineyards
5C (Teleki)
riparia x berlandieri Moderate vigor Wide range of soils: chalky, clay, compact Moderate Lime tolerance Very low drought resistance High phylloxera resistance High nematode resistance Suitable for quality vineyards in northern regions. Poor (K) uptake.
5BB (Teleki Selection Kober)
riparia x berlandieri High vigor Wide range of soils: cold, fertile, permeable Moderate Lime tolerance Low drought resistance High phylloxera resistance high nematode resistance Poor uptake of K and Mg. Not to be used with coulure-sensitive varieties in fertile soil
SO4 Selection Oppenheim
riparia x berlandieri Moderate vigor Fertile, humid, cold soil Moderate lime tolerance Very low drought resistance High phylloxera resistance low nematode resistance Very fruitful. Most popular in EU. Poor uptake of MG --> coulure and stem atrophy. Several clonal variations available.
125AA (Kober)
riparia x berlandieri high vigor Very wide range of soils Moderate lime resistance Moderate drought resistance High phylloxera resistance Moderate nematode resistance Not recommended for varieties sensitive to coulure
berlandieri x rupestris
good for planting in dry and stony conditions. Deep or semi-deep rooting systems. Vigorous. Good resistance to chlorosis and drought. Better lime tolerance than straight resistance.
99R (Richter)
berlandieri x rupestris Very high vigor Prefers soils with average fertility, deep and permeable Moderate lime tolerance moderate drought resistance Very high phylloxera resistance High nematode resistance Fruits well. Used in South of France
110R (Richter)
berlandieri x rupestris very high vigor deep, poor, clay-calcareous soils moderate lime tolerance high drought resistance high phylloxera resistance moderate nematode resistance Good rootstock for dry regions. Poor uptake of K and Manganese
140 RU (Ruggieri)
berlandieri x rupestris Very high vigor Poor, dry soils High Lime tolerance High drought resistance High phylloxera resistance Moderate nematode resistance Suitable for Mediterranean vine growing countries
1103 P (Paulsen)
berlandieri x rupestris Very high vigor Poor dry soils with average compactness Moderate Lime tolerance High drought resistance high phylloxera resistance moderate nematode resistance saline resistant warm climate rootstock
This rootstock is saline resistant
1103 P. berlandieri x rupestris
Berlandieri x vinifera
good resistance to lime and chlorosis.
some have poor resistance to phylloxera
Fercal
berlandieri x rupestris Moderate vigor Dry, shallow, calcareous soils Very high Lime tolerance High drought resistance Moderate phylloxera resistance moderate nematode resistance Shows Mg deficiency if K applications are too great
41B (Millardet et de Grasset)
berlandieri x vinifera Moderate vigor Dry, Calcareous soil High lime tolerance Moderate drought resistance low phylloxera resistance low nematode resistance used in Champagne and Charentes. some susceptibility to phylloxera. Good fruiting, good uptake of Mg.
This rootstock has good uptake of Mg
41B
333EM (Ecole de Montpellier)
berlandieri x vinifera Moderate vigor humid, compact soils High lime tolerance High drought resistance High phylloxera resistance Low nematode resistance Used in Champagne, Charentes, Midi. can cause coulure.
Vitis Champini
Important for regions with severe nematode problems, but tends to be extremely vigorous, and unsuitable for high quality grapes
Dog Ridge
Vitis Champini Very high vigor Poor, light textured soils Low lime tolerance Low drought resistance Low phylloxera resistance Very high nematode resistance For use in regions with serious nematode problems, but with lower quality potential than Schwarzman, and weak phylloxera tolerance
High density planting often increases or decreases the total effective leaf area
increases
balance between vine’s root system and its canopy is determined by:
vigor of the vine, planting density, fertility of the soil, and the training system
main drawback of single wire trellis system
shoots often hang down offering no protection to the fruit from sunburn
VSP
non-divided canopy. adopted in places where there is a high risk of fungal disease in order to keep foliage ff the ground and to simplify spraying and trimming operations
cane-pruning and spur-pruning poduce
uniformly trained shoots where all the fruit is in one zone and the shoot tips are in another.
main disadvantage of VSP
shoot density is normally high therefore prone to shade. unsuited to high vigor varieties and to high potential sites
divided canopies (either vertically or horizontally) provide
less shape
Scott-Henry
Vertical, divided trellis system.
Head trained, Cane-pruned
Smart-Dyson
Vertical, divided trellis system
Cordon trained, Spur-pruned
upward and downward pointing spurs create two canopies
can be machine pruned
head training
trunk has a definite head or knob consisting or old wood rather than arms of a cordon. normally subject to cane pruning but may, after spur pruning, be Gobelet. Guyot is a common cane-pruned form of head training.
cordon training
trunk terminates in a cordon and is normally subject to spur pruning
cane pruning
form of winter pruning in which buds are retained on canes including 6-15 buds. usually takes longer to perform by hand than spur-pruning. cane pruning is typical for for vines which have fewer fruitful buds at the base of the canes. cane pruning cannot be mechanized
spur pruning
form of winter pruning where canes are cut back to two-bud spurs. advantages are it takes less time to prune manually and can be easily mechanized
GDC
horizontally divided trellis with shoots trained downward. downward pointing shoots expose fruit and basal bud to greater amounts of sunlight. normally mechanically spur pruned and mechanically harvested. downward shoots also shown to devigorate
U-shaped or Lyre
horizontally divided trellis with shoots trained upward in two curtains. very high cost of construction and maintenance
Prior to planting soil pH should be increased to over ____
6.5%
3 soils additions that raise soil pH
Calcite (Calcium Carbonate), Magnesite (Magnesium Carbonate), or Dolomite (a combination of both)
Guyot
replacement cane-pruned system with one or more spurs. The cane buds grow into shoots that can be used as canes the following year. The spur buds produce shoots that can be used as canes the following year thus preventing the vine from sprawling too far along the trellis.
main advantage and disadvantage of replacement cane pruning
advantage: by limiting the carbohydrate reserves the vine’s vigor is kept under control
disadvantage: requires great skill cannot be mechanized
main advantage and disadvantage of of cordon/spur pruning
advantage: easier to prune and pruning can be mechanized. retain large volume of permanent wood which can provide carbs (important if budburst occurs while frost is still a risk)
disadvantage: vines are more vigorous
bud-rubbing
removal of a potentially undesirable shoot before it has a chance to grow
leaf stripping
done between veraison and harvest to improve canopy microclimate, allow spray penetration, speed manual harvesting. Can take up to 70hrs/hectare
Green Harvesting
for established vines alters leaf to fruit ratio, may allow allow conformity with yield restrictions . Usually bunches on laterals and those nearest the shoot tips are removed.
chlorosis
yellowing of foliage caused by deficiency of iron, nitrogen, magnesium, and/or sulfur
Cultivation vs. “no-till cultivation”
No-till cultivation is done chemically
sucrose
sugar generated in leaves converted to glucose and fructose in grapes
enzyme
catalyst for reaction
resveratrol
a phytoalexin, protects plant from fungal disease
planting density
way of controlling division of soil resources amongst right number of plants
partial root drying
used to trick vine into allocating resources to fruit ripening rather than vegetative growth
viticulture raisonee (La Lutte Raisonee)
‘the reasoned fight’ supported by the Terra Vitis Organization
photosynthesis
12CO2 + 11H2O –> C12H22O11 + 12O2
hydrolysis of scurose
C12H22O11 + H20 –> C6H12O6 + C6H12O6
Sucrose + Water –> Glucose + Fructose
Sweetness of sugars
Fructose, Sucrose, Glucose is the least sweet. Plants prefer Glucose leaving Fructose as the principal sweetener in sweet wines
Malic Acid
L. Malus = apple.
As the grape matures Malic Acid level diminishes. Because grape consumes malic acid as an energy source, then guconeogenesis
Tartaric Acid
L. Tartarum = deposit
formed as a byproduct of the synthesis of sugar. main acid in finished wine and unique to grapes. table acid so quantity rises in proportion to sugar production
phenolic compounds
Non-flavanoids, and flavanoids (polyphenols)
polyphenols can be sub-divided into tannins and anthocyanins
non-flavanoids
smaller molecules based on benzoic acid and cinnamic acid. influence on flavor relatively minor
Hydrogen Sulfide
H2S
oxidation of alcohol
CH3CH2OH + O2 –> CH3COOH + H2O
Ethanol + Oxygen –> Acetic Acid + Water
Reductive Taint
Sulphur Dioxide becomes chemically reduced to Hydrogen Sulphide
Potassium Metabisulphite
white powder stable when dry liberates SO2 when wet
used in the vineyard to protect grapes en route to winery
CO2
cheap and effective antioxidant
but soluble in wine (more soluble at lower temp)
around 800mg/l in whites and pinks important constituent
Argon
expensive but effective alternative to CO2 and N
Dissolved O
every molecule of oxygen destroys 4 times its weight of SO2
2SO2 + O2 –> 2SO3
128 32
Sparging
process of injecting fine bubbles into a liquid usually to remove dissolved oxygen. usually mixture of CO2 and N.
Sparging does not remove oxygen exclusively but will remove anything volatile (flavor components are volatile)
Must
product of crushing is known as must from Latin Mustum meaning fresh or new.
White wine - Juice
Red wine - Juice + Skins
Crushing
ripping open grape to allow free-run juice to flow out
optional: crush or leave intact for direct pressing
Pressing
extraction of juice remaining after crushings
principle of pressing: use minimum pressure required to achieve necessary extraction
pectinolytic enzymes
releases more juice from the pulp by breaking down gelatinous pectins
Draining
draining process is slower than other stages and can pose a problem of through-put
free-run juice
for whites free-run juice is typically between 400 and 500 litres per tonne
Pressing the berries
pressing comes after juice released from crushing to release remainder of juice (150 to 200 litres per tonne of grapes)
basket press
vertical screw press
simple and effective. Bed of skins acts as a fine filter yielding juice of good clarity. Presses used for Champagne based on Basket model
issues: cannot be rushed, must exposed to oxygen
Horizontal Screw Press
Vaslin press
screw is divided into two halves: one right-handed, one left. chains to break up mass of skins
can be completely automated
but juice produced tends to be rather course due to pressure and abrasion of skins due to tumbling action of press
Pneumatic Press
more efficient pressing at lower pressure
common fault is exposure
Tank Press
enclosed Pneumatic Press
Continuous Screw Press
efficient, but produces rough juice
Whites: Clarification
whites: unfermented must is very susceptible to oxidation almost always protected but SO2 (also to protect from premature fermentation)
exception: hyperoxidation
Reds: Clarification
red must somewhat impervious to SO2.
red must contains skins which have a high population of microorganisms that cannot be totally controlled by SO2. Some of these organisms produce acetaldehyde which binds with SO2 removing free SO2. SO2 also combines readily with some of the anthocyanins.
Many winemakers use SO2 however because improves extraction of polyphenols
Calrification
solid particles are nutritious to yeasts because they have become adsorbed to the surface of amino acids, minerals, and vitamins
Ways to clarify
settling - takes time. SO2 protects must from oxygen and reduces activity of yeasts and bacteria. So temp cooled to below 15C which will slow microbial activity and oxidation. At the same time Oxygen more soluble in cool wine
centrifuging - fast but harsh. exposure is an issue. Can be used at any stage of wineaking
flotation -Can be used for dual purpose of clarification and hyperoxidation by using O rather than N
Hyperoxidation
counterintuitive: kills more susceptible components of the juice, finished wine is more stable
Acidification
usually tartaric, citric is cheaper but can be metabolized by some yeasts and converted to acetic,
plastering
adding plaster or gypsum (Calcium Sulphate). old Jerez practice. Increases acidity by precipitating calcium tartrate and leaving more acidic potassium bisulphate in solution.
more effective to simply add tartartic acid
Deacidification
add a carbonate
Chalk (calcium carbonate) or potassium carbonate neutralize acids in the must
addition of chalk removes mainly tartaric acid, product is calcium tartrate the crystals of which is difficult to remove being equally soluble at all temps
adding potassium bicarbonate crystals result in potassium bitartrate which is very easy to cold stabalize out
double salt deacification
calcium tartrate-malate, complex double salt that eliminates both tartaric and malic acids by forming Calcium Tartrate-Malate which is very insoluble.
Does require malic and tartaric acids to be present in roughly equal proportions.
vacuum distillation
concentrating must by boiling must at very low pressure
gaseous nitrogen
N2
Combined nitrogen
in the form of ammonium NH4. N is necessary for the formation of amino acids/proteins within the yeast cell
insufficient nitrogen
fermentation is reductive, in the absence of nitrogen production of hydrogen sulfide. adding diammonium phosphate or ammonium phosphate up to 1g/litre
Thiamine
important for growth of yeast populations. allowed to add up to 0.6g/litre
Bentonite
sometimes added at must state to remove proteins in order to reduce viscosity. another advantage is will remove polyphenoloxidase
activated charcoal
if white wine must is deeply colored treated with up to 100g/l
saccharomyces
means sugar-loving
cerevisiae is the most common. It is tolerant of both alcohol and SO2. bayanus associated with sherry production
alcoholic fermentation
in the absence of oxygen
yeasts + sugars –> alcohol + CO2 +heat
C6H12O6 –> 2C2H5OH + 2CO2
Glucose Ethanol Carbon Dioxide
180 92 88
ethanol weight
0.7897 g/ml
17g sugar/l produces 1% alcohol by volume
temperature
extraction of flavor and color components from the skin on one hand, retention of volatile aromatic substances on the other
reds fermented at 20 - 30C (whites at 10 - 18C)
ways to stop fermentation
1) naturally
2) increase CO2 pressure
3) reduce temperature
4) kill yeasts
5) remove yeasts
6) fortification (results in stable wine)
naturally sweet wines
factors slowing fermentation
1) shrinking of yeast cell by osmotic pressure (dehydration) due to very high sugar concentration
2) nutrients gradually exhausted
3) botrytised grapes have anti-fungal properties which inhibit alcoholic fermenetation
ML
wines with very low pH will not undergo ML
Lactobacillus, Leuconostoc, Pediococcus are naturally present in wine and will start spontaneously
Oenococcus oeni can be purchased.
to encourage ML raise temp avoid SO2. Do discourage lower temp add SO2
pigeage
punching down cap or chapeau
see also pumping-over method
submerged cap process
screen method, prevents efficient extraction
delestage
(rack and return). similar to pumping-over
rotary fermenters
very effective achieves thorough mixing of skins and juice. However serve disturbance can lead to overextraction
thermovinification
heat crushed mixture to 60-75C for 20 to 30 minutes. Anythoycyanins readily extracted at elevated temperatures.
Beaucastel - after destemming heated rapidly to 90C. Anthocyanins easily extracted. Also destroys the polyphenoloxidase that causes premature oxidation requiring lower dose of sulphur
Flash Detente
95C for a several minutes then immediately subjected to a low vacuum where the cells are ripped apart
widely used for Cotes du Rhone
Carbonic Maceration
intracellular followed by extracellular fermentation
anaerobiosis
press juice is of better quality than free run
Whole bunch fermentation
different styles of Beaujolais are dependent upon length of time the berries are left to macerate. Beaujolais Nouveau is racked off after about one week, whereas higher grade is left up to a month
pink wine methods
1) short maceration
2) saignee
3) Vin d’une nuit
4) double pasta
maceration pelliculaire
skin contact particularly useful for aromatic whites
batonnage
stirring introduces oxygen to the lees which prevents reduction, also increases contact with lees increases leesy flavors
Pompe Bicyclette
carbonation
Fortified Wines
according to EU legislation now called “Liqueur Wines”
oxidative coupling
tannins and anthocyanins interact creating stable coloring matter
Quercus Alba
American Oak (Penn, Minn, Wisc)
Quercus Robur
English Oak or Pedunculate Oak.
Limousin is only forest.
Has a coarser grain and a lower aromatic content particularly useful for agin Cognac
Quercus Sessilis
Found in most French Forests i.e. Troncais, Nevers, Allier, and Vosges.
has a tight grain and is rich in aromatic content
Slavonian Oak
Quercus Robur
IPM
focused on timely preventative measures rather than more costly curative ones
Botrytis cinerea
Grey mold, grey rot, …
heavily infected white grapes will require more SO2, red grapes will require charcoal fining to remove mouldy taint
sclerotia
botrytis overwinters as sclerotia (hard, dark-brown encrustations of the dormant fungus)
bunch rot
when botrytis infects flowers can get trapped in center of bunch as grapes expand
pre-emergence herbicides
become trapped in soil absorbed through roots
systematic herbicides
absorbed by the leaves
contact herbicides
‘wilters’ are only temporary for plants with established root systems
obsolete botrytis treatments
Benzimidazole in the 60s and 70s, then dicarboximides both of which were contact fungicides. Botrytis can become resistant to certain chemicals
Scala
systematic herbicide for prevention of botrytis. active ingredient pyrimethanil. introduced in 1995. only 3 applications per year but is very effective and has only 7 day harvest interval
Sentinel
bio-fungicide developed in NZ for preventing botrytis using new strain of predator fungus called Trichoderma harzianum. as effective as other products.
Stem rot
bortytis infects stems reults in large numbers of bunches to fall to the ground
methods to control botrytis
1) spraying chemicals
2) open leaf canopy to allow air movement
Noble Rot
Once grapes reach about 7% potential alc. botrytis affects them differently. grapes must be clean prior
Downy Mildew
will infect any green part of the vine. Grapes if infected turn leathery and will impart moldy taint to wine. Treated with copper which is particularly effective if used as post-harvest, pre-winter spray to control through dormant period
Bordeaux Mixture
blend of lime and copper sulphate. Alternatives are copper oxichloride and copper hydroxide which both require less prep and are less likely to persist in the soil
Oidium or Powdery Mildew
treated with sulphur. Does not require water to transmit air with sufficient moisture is sufficient. Attacks leaves with white powdery covering and causes young berries to split exposing seeds. harvest interval between 21 and 56 days
alternatives to sulphur for treatment of Powdery Mildew
light mineral oil which is also effective on botrytis, and Strobilurins which are sprays developed from a toad stool called Strobilurus Tenacellus.
Anthracnose
fungal disease but easily controlled with copper-based sprays
Armillaria Root Rot
attacks roots, problem in vineyards planted on land that was once wooded. Control is almost impossible. only remedy is to keep land fallow, plow deeply to expose and destroy old tree roots
Bacterial Blight
only method of control is to remove infect vines and disinfect secateurs before pruning each vine. Copper sprays help
Black Rot
impossible to eradicate but controlled with copper sprays
Crown Gall - Black Knot
spread through grafting process. vines become infected following damage to vine after frost has spit trunk. Prevented by Buttage. In New York growers train multiple trunks from base so that if one becomes infected it can be cut off and vine remains productive.
Buttage
ploughing close to vine so earth is piled up around and over the graft prior to winter.
Esca
caused by several different fungal pathogens, more common is warm to hot regions. Shows up leaves as light colored areas between veins and necrotic leaf edges, dark speckling will occur on grape. Controlled by keeping vineyard clear of old wood, disinfecting pruning wounds, and avoiding pruning systems with large amounts of permanent wood
Eutypa
fungal disease caused by Eutypa lata. rarely shows in young vines manifests as malformed, chlorotic leaves. Only control is to avoid systems with a lot of permanent wood, removing old wood and burning, disinfecting wounds with fungicide. Sometimes can rejuvenate infected vines by taking shoots emerging near the ground and completely retraining the trunk
Grapevine Yellows - Flavescence Doree
group of related diseases caused by phytoplasma (similar to bacteria). Spread by sap-feeding insects and by using material infected in the grafting process. Infected vines have curling yellow leaves.
Phomopsis - Dead Arm
controlled by copper sprays
Pierce’s disease
caused by bacterium Xylella fastidiosa spread by various insects
Corky Bark
Viral. Infected vines have red or red/yellow leaves which tend to curl downward, canes become grooved, areas on the main stems expand and turn corky.
Fanleaf Degeneration
Viral. Leaves distort and grow in shape of a fan. Then leaves become yellow with yellow veins. Nematodes are vectors
Leafroll
Viral. rolling of the leaves, slight veining, and color change from green to bronze to red. grapes tend to take longer to ripen and may not achieve sufficient sugar levels
Nepoviruses
group of 13 viruses spread by nematodes
heat treatment of cutting
50C for 30 minutes
Phosphorous
on soils with very low pHs, low P levels may lead to chlorosis-like symptoms
Potassium Deficiency
Vines deficient in K will show chlorotic leaf margins, often accompanied by cupping of the leaves.
Soil Potassium
Excess K in soil often associated with high pH in wine. Soils high in K tend to be deficient in Mg
Iron
Iron is required for chlorophyll production. deficiencies associated with high pH soils
Chlorosis
high pH soils (7.5 +) fix iron which is required for photosynthesis
Coulure
poor flowering conditions and/or an imbalance of nutrients
Millerandage
condition resulting in un-pollinated flowers or very small berries sans seeds
Barrique
Bordeux. 225 litres
Gonci
Hungary. 130 litres
Micro-Oxygenation
main effect is change in polyphenolic structure. best wines for this treatment are high in both tannins and anthocyanins.
two phases: Structuring and harmonisation
Ethyl Acetate
Principal Ester results from volatile acidity. which is the result of acetobacter. Wines with excess VA smell of varnish because acetic acid forms ethyl acetate
VA
EU limit for reds is 1.2g/l. EU limits for whites and pinks 1.08g/l. VA becomes noticeable around 0.8g/l. 0.4 to 0.5 g/l is normal.
RS
mainly fructose because yeasts ferment glucose preferentially. If sucrose was added (i.e. champagne) will have been inverted by acides to equal parts glucose and fructose
glycerol
major byproduct of fermentation originating from sugar in juice. legs are thought to be due to the surgace tension effect of a combination of glycerol and alcohol. Grapes infected with Botrytis already contain glycerol as a reult of the metabolism of the grape sugars by noble rot + more glycerol from fermentation. Botrytised wines contain a lot of glycerol.
Acetaldehyde
precursor of ethanol during fermentation also product of its oxidationt
yeast bitten
wine that has been left in contac for too long with the gross lees is said to be yeast bitten
Finingg
process of clarification that is used for 2 purposes: 1) to prevent haze, and 2) to remove some of the tannins to improve the balance of the wine
Colloids
Stabe vs Unstable
Acacia (gum arabic) is a stable colloid used to increase wine stability
Ox Blood
prohibited in EU since 1987. Active ingredient is Albumin
Albumin
effective at removing harsh tannins and troublesome colloids
Gelatin
similar to Albumin in structure and effect.
Used to remove harsh tannins from reds. Used in conjuction with Silica Sol for treating white wine
Silica Sol
active substance is silicon dioxide which can be produced in both positive and negative colloidal forms. It is often used with gelatin for removing other protective colloids from white wine.
Similar but less effective than Bentonite
Casein
useful for decolorizing white wines
Tannin for fining
wood tannins used in conjunction with gelatin precipitate first with the gelatin then bring down colloidal proteins
Bentonite
Used to remove heat-unstable proteins from white wines, and to clarify must. Not generally used for reds.
No danger of over fining but forms a voluminous deposit from which it is difficult to recover wine. Effective at adsorbing certain proteins and to a limited extent bacteria
Egg Whites
used in production of fine reds by adsorbing harsh tannins and excess colloids
Oenological Tannins
will inhibit Laccase activity from botrytis on red grapes
Isiglass
like Gelatin reacts with excess tannins in harsh, young reds. Can be used to clarify white wines to be bottled without a final polish filtration.
Expensive and derived from animals
PVPP
used to remove phenolic compounds from whites especially those that are suffering from pinking or browning
Charcoal
used to remove brown colors and off odors
Blue Fining
removal of excess iron and copper. Particularly useful for removing copper as this is the
Calcium Phytate
removes excess iron from red wines by precipitating out as soluble ferric phytate
PVI/PVP copolymers
plastic meterial absorbs metal ions such as iron and copper
Chitin-glucan
polysaccharide and fungal resource used as a fining agent. produced from aspergillus niger
Chitosan
natural polysaccharide produced from aspergillus niger will remove heavy metals (iron, copper, lead, cadmium). Will reduce levels of ochratoxin A.
Will elimate undesireable organisms notably Brettanomyces
Super-Saturation
tartrate concentration exceeds solubility limit after fermentation because they are less soluble due to the presence of alcohol
tartrate crystals
form after colloids denature.
Cold stabalization
potassium bitartrate is much less soluble at low temps so cold stabilization works very well. solubility of calcium tartrate changes very little with temp so cold stabilization works poorly
chill wine to just above freezing (-4C for a wine of 12% alc). Due the protective effect of the colloids, this process only works well if efficient fining process takes place prior
Contact Process
quicker, cheeper, more effective than cold-stabilization. wine is chilled to 0C, finely ground potassium bitartrate crystals are added at a rate of 4/l and the wine is stirred vigorously for 1 to 2 hours
Ion Exchange
prevents crystallization by exchanging calcium and magnesium salts for sodium bitartrate which is more soluble
sodium also replaces potassium however. This process is banned in EU
Electrodialysis
uses selective membranes to allow passage of potassium, calcium, and tartrate ions under the influence of an electric charge.
Very expensive but customizable, reliable, and wine requires very little to no pre-treatment
metatartaric acid
prevents tartrate crystals by an unknown mechanism. Thought to coat colloids preventing crystallization. Cheap and effective, but unstable gradually reverting to tartaric acid causing even more problems than if had not been used. lasts about 6-18 months. Perfect for Bag in Box
EU limit is 100 mg/l
Carboxymethylcellulose
similar to metatartaric acid but lasts longer. EU limit is 100 mg/l
Mannoproteins
wines that mature on lees have greater tartrate stability. this is due to mannoproteins which are released during yeast autolysis.
added to wine day prior to bottling dose of 200 to 250 mg/l. stable and long lasting. Permitted in EU and Argentina. Pending in USA and AUS
Sulphurous Acid
SO2 + H2O –> H2SO3
Potassium Metabisulphite
K2S2O5
releases 57% of its weight when dissolved in acid aqueous solution
Sulphur Dioxide disadvantages
1) some people are allergic
2) bleaches color of red wine and can result in loss of fruit (although wine does partially recover when free sulphur levels have diminished
Sulphur Dioxide Antioxidant
readily combines with Oxygen
H2SO3 + [O] –> H2SO4
Sulphurous Acid + O –> Sulphuric Acid
it is however possible for oxygen and sulphur dioxide to coexist before reaction takes place
Sulphur Dioxide Anti-Mircrobial
Acetobacter is aerobic, so controlled by SO2 which also controls O which Acetobacter needs.
antiseptic property also used to prevent ML by attacking lactobacillus
Sulphur Dioxide Anti-Oxidasic
SO2 controls oxidases
Sulphur Dioxide after oxidation
Can freshen wines suffering from a degree of oxidation
one of main products of oxidation is acetaldehyde which SO2 binds with converting it into an odorless and tasteless bisulphite addition compound
Free and Total SO2
badly made and oxidized wines have a higher proportion of aldehydes and ketones thus greater proportion of SO2 becomes bound
EU regulates total SO2 150mg/l for dry red to 400 g/l for botrytized wines
Molecular SO2
SO2 + H2O H+ + HSO3-
Only molecular SO2 possesses protective properties. At low pH wines have higher portion of Molecular SO2 and therefore require less of it
Ascorbic Acid
turns to Hydrogen Peroxide when oxidized. therefore SO2 must be used in conjunction. Used in GER, NZ, AUS because keeps whites ultra fresh. Isomeric form Erythorbic acid used in AUS instead (because it is cheaper) but not allowed in wines sold in EU
Sorbic Acid
Not a fungicide but does prevent fermentation by interfering with yeast metabolism. Dependent on presence of SO2, alcohol, and acidity. EU limit of 200 mg/l but most bottle at 150 which is fine for 12% wines.
Wine containing sorbic acid must be free of bacteria. Must be added just prior to aseptic bottling because has no bactericidal properties. Can cause smell of geranium leaves when metabolized by bacteria by forming 2-ethoxycarbonyl-3,5-hexadiene.
Citric Acid
added to wines with excessive amount of iron. Prevents Iron casse by forming soluble complex with iron.
must be added to finished wine because yeast will convert into acetic acid
Copper Sulphate or Silver Chloride
Hydrogen Sulphide results from reduction of SO2. Copper binds with hyrdrogen sulphite and precipitates as copper sulphide.
Silver Chloride used for the same purpose
Acacia
Gum Arabic is a stable colloid that will prevent crystallisation of tartrates. Must be added after cold stabilization because it will prevent crystallization during chilling process
Pectinolytic enzymes
when added to grapes in press decreases viscosity of juice allowing better extraction.
Can also be added to must after pressing. Reduction in viscosity enables a quicker and more effective clarification.
Betaclucanase
B-Glucan which results from botrytis infection or grapes that suffered attack of grey mold is a large molecule and block all membrane filters. Betaclucanase added after fermentation eliminates B-Glucan.
Another method of overcoming filtration problems is by heating wine to 25C B-Glucan molecules change shape, the viscosity of the wine drops and wine becomes filterable
Lysozyme
found in protective fluids (tears, saliva, mucus). kills certain types (gram positive) such as Oenococcus oeni, Pediococcus, and Lactobacillus thus preventing or delaying ML. Has no effect on gram negative bacteria such as acetobacter or on yeasts
Laccase
present in grapes that have been attacked by botrytis. It is a polyphenoloxidase and will turn wine deep gold or even brown. This is a major problem with red wines
Tyrosinase
a polyphenoloxidase that is present in healthy grapes. It is susceptible to SO2 therefore not too much of a problem.
depth filtration
kieselguhr (earth filtration) or sheets (pad filtration)
rotary vacuum filter
filters course liquid. used primarily for the lees. disadvantage is exposure and risk of oxidation
earth filter
totally enclosed and can be flushed with nitrogen. Machine is expensive but Kieselguhr is cheap and available in a variety of particle sizes allowing everything from simple clarification to yeast removal.
Sheet filters (plate and frame or pad filters)
used after the gross solid matter has been removed. It is possible to remove microorganisms with the finest grade of sheets. These are known as sterilizing sheets and are frequently used for removing yeast and bacteria prior to bottling
Membrane (cartridge filters)
can only be used as final filtration of wine that is already very clean. Unlike depth filtration units the equipment is cheap but the filters are expensive.
Membrane filter sizes
- 2u largest size will remove most yeasts
- 8u removes all yeast but not all bacteria
- 45u removes all yeast and all bacteria
wines that are most susceptible should be filtered at 0.45u. wines that are less susceptible can be filtered less finely
crossflow filtration
can filter extremely dirty liquid to bottling standard in one pass and can be fitted with appropriate size of membrane. very expensive but only form of filtration needed
Ultrafilltration
uses extremely small membranes that can actually filter out individual components of wine
