Winemaking Flashcards
What is the grapevine species for Niagara and Concord that has a notable ‘foxy’ aroma?
Vitis labrusca
What is the North American grapevine species that is very winter hardy and great for hybrid grapes? e.g Baco Noir, Triumph d’Alsace
Vitis riparia
What is the grapevine species that is from the Southwest US and used to breed rootstock for grafting and hybridization?
Vitis rupestris
What is the grapevine species that uniquely requires pollination and is native to the Southeastern US? e.g Scuppernong
Vitis rotundifolia
Define ‘cross’
intrA-specific breeding (same species)
Define ‘hybrid’
intER-specific breeding (different species)
Define ‘clones/cultivars’
Different varieties within the same species
What is an example of an exceptionally old vineyard that has been site selected?
1) Clos Vougeot in Cotes du Nuits, Burgundy
2) Clos de la Coulée de Serrant in Savennieres, Loire Valley
Define ‘degree days’
Measurement of total heat over the course of a growing season by adding the high temperatures over 10ºC for the season.
What is considered to be the minimum degree days for viticulture? What factor can influence this?
1100; microclimates allow this number to be lower if the conditions are right
Define ‘frost-free days’
Length of the practical season.
What are some human methods to length the frost-free days?
Wind machines or heaters
Slope in a vineyard can draw cool air down just like water, settling at its lowest point. What is considered the minimum slope best o plant to prevent frost prone areas settling in your vineyard?
5%
What is the ideal relationship between water and vines?
Vines will be slightly stressed throughout the ripening cycle.
What are the 5 primary reasons vines are grated onto rootstock?
1) pests resistance
2) suitability to soil chemistry
3) drainage
4) vigour
5) growth habitat
What common rootstock is a Berlandieri x Riparia cross that is known to be adaptable and produce strong yields but is not suitable in dry soils.
S04
What rootstock the child of Riparia x Rupestris and has low-medium vigour and is suited to deep soils, good drainage and cool climates.
3309 Couderc
What is a Riperia rootstock that has low vigour, suitable to very well drained sites and needs proper fruit yield management?
Riparia Gloire de Montpellier
What is a Riparia x Rupestris cross rootstock that is suited to moist and deeper soils (e.g clay) and has moderate vigour?
Millardet and de Grasset 101-14
What rootstock works well in acidic soils?
Gravesac
What rootstock is lime tolerant?
140 Ruggeri
What rootstock is good for low vigour varieties?
Kober 5BB
In the eyes of a viticulturist, when does the grow cycle begin?
As soon as the grapes are off the vine.
When does pruning of he canes happen?
Over the winter
When does bud-break usually occur in the Northern/Southern hemisphere?
As early as March in Northern hemisphere and September in the Southern hemisphere.
At what point does flowering begin after bud-break? How long does it last?
Between 1.5-3 months later. Lasts up to 2 weeks.
Define ‘hermaphroditic’ in terms of grapevines?
Self-pollinating
When does fruit set / veraison happen occur in the Northern/Southern hemisphere?
July - Northerns
January - Southern
What changes occur during veraison?
Skins soften
Colour changes
Sugars accumulate
How far down do you plant a new vine/rootstock?
~50cm
In temperate climates, what time of year is preferred for planting new vines? Why?
Fall because the surrounding soil has the winter to settle and warm up gradually in the spring.
In Northern climates, what time of year is preferred for planting new vines? Why?
Spring to avoid the possibility of frost damage over the winter and allows for the use of potted vines.
What are potted vines?
Vines that have been raised in greenhouses that have the benefit of a year’s growth before being planted.
What is the different between the brand categories of cane and spur pruning methods?
Cane pruning is where a full cane or more is laid down and spur pruning is when the canes are cut back to a couple of buds on a spur.
Is this an example of cane or spur pruning?
Spur
Is this an example of cane or spur pruning?
Cane
What are some factors that define a growers choice on trellising system? (7)
1) Site
2) climate
3) vigour
4) growth habit of the wine
5) bud viability
6) yield expectation
7) tradition
What are the 3 main types of trellising?
1) Bush vines (no trellis needed)
2) Single or double canopy
3) pergolas
What is the importance of canopy management?
1) Avoiding overgrowth
2) Increasing airflow
3) reduce disease
4) better coverage of spraying
5) sun exposure
6) protection from wind, machinery and the weight of the grapes themselves
Describe the signs, effects, conditions and treatment for downy mildew (plasmopara viticola).
Signs: oil spots on the vine leaves or reddish-purple mummified berries.
Effect: reducing photosynthetic potential
Conditions: temperate, wet and humid
Treatment: synthetic chemical sprays or copper sulphate
Describe the signs, effects, conditions and treatment for powdery mildew (uncinula necator).
Signs: white-powder substance on any part of the vine
Effects: prevents further growth of organs, grapes dry out and crack open, overwinters on the vine and can cause rapid outbreaks in the spring
Conditions: warm / hot, humid
Describe the signs, effects, conditions and treatment for botrytis cinerea.
Signs: dry, shrivelled berries
Effects: can be positive if it is followed by dry conditions and grapes see sugar concentration but if its followed by wet weather, it can ruin the whole crop
Treatment: good airflow and synthetic sprays
What is the pest that carries Pierce’s Disease via bacteria? How is it managed?
Glassy Winged Sharpshooter; careful scouting and aggressive spray programs
Describe the signs, effects and treatment for black rot (guignardiaa bidwellii).
Signs: small brown spots on the leaves, black elliptical marks on the shoots
Effects: grape turns black and mummified, results in large loss of crops
Treatment: microscopic sulphur
What part of the plant does phylloxera attack? What is the only prevention?
The roots; grafting onto American rootstock
Why is Chile seemingly safe from phylloxera?
Strict important laws and natural geographic boundaries.
What pest may not have entirely damaging effects on a grapevine, but does reduce the overall photosynthetic potential of it?
The European Red Mite
What animal wears a mask and loves snacking on grapes?
What are some prevention methods for birds in a vineyard?
Scare tactics, nets, and falconry.
Name the 6 general types/categories of equipment found in a vineyard.
1) Tractors
2) sprayers (tow-behind or hand-held)
3) Hedger (single or doubles-sided)
4) Leaf remover
5) Soil implements (harrows, plows, sub-boilers, and tines)
6) Under-the row (cultivators, mowers, blades)
Two most prominent types of sugar in grape.
Glucose and fructose.
True of False: Tartaric and acetic acid are the two main acids found in a ripening grape.
False: tartaric and malic
What acid decreases first during ripening?
Malic
In hot climates, what often has to happen with acidity levels in wine processing? Why?
Addition of acid because the grape ripens quickly and acid levels fall quickly.
In cold climates, what often has to happen with acidity levels in wine processing? Why?
Malolactic or de-accidification due to high ratio of malic acid.
What is pH a measure of? What influences does it have on the wine?
The acidity or basicity of a solution. It influences the colour, mouthfeel, balance and development of the yeast and bacteria.
What compound includes tannin and anthocyanins? What are they responsible for?
Polyphenols; colour in a wine.
As acid level drops, pH level ___________.
Increases
What are the benefits and draw-backs of hand-picking grapes over machine harvesting.
Hand picking is more gentle, gives whole clusters and can selectively take or leave grapes at their optimal point. Machine harvesting is must more efficient but it can damage berries in the aggressive process.
What can be done to slow down oxidation and preserve acidity of berries when machine harvesting?
Pick at night.
What is the standard wine yeast called.
Saccharomyces cerevisae
What does yeast need to perform its task of converting sucrose to ethanol?
Nitrogen, carbon (fermentable sugars), oxygen, various vitamins and minerals.
How is sucrose broken down into glucose and fructose in order to be fermentable?
An enzyme called Invertase.
What are some bi-products of fermentation?
Co2, volatile acidity, acetylaldehyde, esters.
What does ‘killer characteristics’ mean in reference to yeast.
This is in reference to cultured yeasts strains that have been selected for their ability to suppress other yeast strains by secreting toxins.
True of False: In a native yeast fermentation, there is many different strains involved.
True
What is the type of yeast called that can affect a fermentation both positively, by adding complexity, or negatively, by spoiling it completely?
Spoilage yeast
What are the two most common aroma compounds found in Brettanomyces?
4-ethylphenol = barnyard, horse
4-ethylguaiacol = clove
What can Kloeckera apiculata do to a fermentation?
Significantly increase volatile acidity.
What is a natural antioxidant of wine as a bi-product of fermentation?
Lees
Why can stuck fermentations result in an increase in volatile acidity?
The un-fermented sugars are digested by malolactic bacteria, instead of the malic acid, producing VA.
Why can a stuck fermentation cause reduction in a wine?
The lack of oxygen and nitrogen in a wine must as the yeast struggle and cause reduction.
Define ‘reduction’ in a wine.
The presence of volatile sulfur compounds created during fermentation that manifest in the form of rotten egg and rubber smells.
Name the aroma family that produces fruity aromas as a result of acids and alcohol.
Esters
Name the aroma family that produces fruity to onion/garlic aromas. They are classic of varieties such as Sauvignon Blanc.
Mercaptans (Thiols)
Name the aroma family that produces floral, fruity and resiny aromas as a result of grape skins. These are classic Muscat or Riesling aromas.
Terpenes
Name the aroma family that produces bell pepper or other herbaceous aromas. These are classic of the Carmenet family of grapes.
Methoxypyrazines
Define ‘chaptalization’.
The addition of sugar to increase potential alcohol. This can be added up until about halfway through a fermentation and usually at a maximum of 2-4%. This is more common in cool climates.
Define ‘acidification’.
In warm climates, sometimes adding tartaric, malic, and citric to add freshness and bring the pH down to a stable level.
What are two chemical products to de-acidify a wine by removing tartaric acid?
Calcium carbonate and potassium bicarbonate.
Why would tannins be added to a wine?
To stabilize colour and help prevent oxidation.
A bacteria called oenoccocus oeni is responsible for the conversion of malic acid to lactic acid. What is this process called?
Malolactic fermentation
What are the ideal conditions of malolactic fermentation?
pH > 3.3 + alcohol < 15% + temperature > 18ºC
What are some reasons why not only red winemaking, but white winemaking too can benefit from MLF?
A) Reduction in acidity e.g sparkling base wines
B) Rounded mouthfeel as part of the style e.g barrel-fermented Chardonnay
What does cold maceration do in white winemaking? What happens if this is over-done?
This can increase the phenolics in aromatic grape varieties but it can extract too much colour or bitterness if it’s left for too long. Typical soak time is 6-24hrs.
What is the benefits and drawbacks of whole cluster pressing?
Clearer juice but loss of flavour and aromatic compounds.
What is the ‘hard press’?
The highest pressure used to extract juice from grapes, containing more phenolic compounds and less acid.
What are a couple undesirable aromas that are a result of the lees being fermented?
methionol - cooked cabbage
dimethyl sulfoxide - burnt rubber
What are two different methods to clarify a wine prior to fermentation?
a) Let it decant at cool temperature (<12ºC)
B) Pectolytic enzyme is added to break apart larger compounds (bonus: this can release terpenes that will result in that desirable Muscat aroma)
What temperature are light, crisp white wines generally fermented at?
12-15ºC in stainless steel
What temperature are richer styles of white wines generally fermented at?
15-20ºC in new or used oak barrels
What is proteinaceous haze? How is this treated?
Some wines produce excess protein in solution that can become denatured when under hot conditions. This creates a haze that is a combination of protein, minerals and phenolic compounds. This is tested by heating up a sample to 80ºC for 30 mins to see if there are changes in clarity. If so, there are a number of additives to treat protein instability or heat treatment.
What are some additives to treat protein instability? (3)
1) benonite - negatively charged absorbent clay
2) isinglass - collagen from fish bladder
3) casein - milk protein
What are the potential results of oxidation in wine?
a) unpleasant aromas
b) loss of colour
c) make wines ‘go flat’
d) bacterial or enzymatic infections
How does SO2 act to prevent oxidation in wine?
It acts as both an antiseptic and an anti-oxidant by giving the wine more ‘free’ so2 than the natural levels it already contains. This means less bound with oxygen. Sweet wines need a higher level to prevent oxidation.
What inert gases (3) are commonly used for preventing oxidation in wine by forming a protective barrier because they are heavier than air?
Nitrogen, argon, and carbon dioxide.
Polyvinylpolypyrolidone (PVPP) is an anti-oxidant that doesn’t prevent oxidation but reduces the potential for it occurring. How does it do this?
It bonds with polyphenols in the wine and sediments.
Explain the reverse psychology that is hyper-oxygenation to prevent oxygenation.
Hyper-oxygenation is done prior to fermentation to get the oxygen to react and bind to tannin and polypeenolics, causing them to drop out of the wine and making them less prone to oxidization later on.
What are the two ways to prevent tartaric instability?
a) Passing the wine over an ion-permeable membrane charged with electric current that cause the excess tartaric acid to drop out of solution.
b) Crystallize the excess acid by lower the temperature of the wine to -1 - 0ºC and cream of tartar is then added to make it crystallize and settle at the bottom of the tank. Wink is then racked off.
What are the 4 different types of filtration systems for white wine?
1) plate filter - diatomaceous earth or perlite
2) plate filter - cellulose, can do sterile filtration
3) membrane filters - cylindrical cartridges, can do sterile filtration
4) cross-flow filtration - sterile filtration not possible but very efficient, long lifespan and can limit the use of so2
Sulphur dioxide, heat treatment, micro filtration and additives such as sorbic acid and lysozyme are all examples of what step in wine making? How does each work?
Microbial stabilization
SO2: microbes such as ones in MLF and those in wild yeast spoilage cannot survive in the presence of higher concentrations of so2
Heat: usually mass produced wines do flash pasteurization to ºC for 30 secs
Microfiltration: almost all wines are sterile filtered prior to bottling
Additives: yeast or bacterial-inhibition, especially wines with RS.
In red wine making, whole clusters of berries can either be fermented with or without being destemmed. What factors might influence a winemaking to not remove the stems prior to fermentation?
If the grapes are very ripe and the stems are mature, it will impact less harsh tannins.
How long does alcoholic fermentation typically last for red wines?
7-10 days
At what temperature range is a red wine likely to be fermented at? At the lower end of the range, what type of wine style can you expect?
25-30ºC; lighter and less extracted wines
What are the 3 techniques winemakers use to encourage contact with skins during the fermentation process?
1) Punchdowns: plunging down the cap
2) Pump-overs: pumping clear wine from the middle of the tank back over the top, either gently or aggressively
3) Rack-and-return: pumpover where all the liquid is removed from the vat and aggressively pumped back over the skins
What is an alternative name for the rack-and-return method?
Delestage
What is a winemaker trying to achieve if they choose to further macerate the wine on its skins post-fermentation?
Extract more tannin and build more structure.
Why is the ‘hard-press’ juice often kept apart from the ‘free-run’?
It can contain bitter compounds.
Maturation is necessary in red winemaking for what process to occur?
MLF
Colour in red wine is courtesy of two phenolic compound families, what’re they called and what do they contribute?
Flavonoids and non-flavonoids. Flavonoids are divided into 3 groups:
1) Anthocyanins = red/blue hues
2&3) Flavan-3-ols and tannins = polymerization with anthocyanins allows the creation of a wide range of colour
What are some factors, other than flavonoids, that can influence the colour of a red wine?
pH, age, so2, and co-pigmentation with other phenols
What are the 4 methods of stabilizing a red wine?
1) egg whites
2) gelatine
3) gum arabic
4) cold stabilization
What needs to be low in the base wine of a sparkling wine in order for the secondary fermentation to occur?
SO2
What is the period of aging during the secondary fermentation of a sparkling wine called?
tirage
In most regions, what is the minimum a sparkling wine must age during triage?
9 months at least but some wines can be much longer
What are some common additives to sparkling wine to assist with riddling and help build structure?
Tannin, bentonite, alginates, or gelatines
What the the mechanical devise that replaces the riddling rack?
A gyropallette
How long does it take for riddling?
A few weeks
What is the wine topped up with post-disgorgement in sparkling wine production?
SO2, wine and sugar
What is it called when the dead yeast cells release compounds such as proteins and polysaccharides that create the rich mouthfeel of a sparkling wine?
Autolyse
What is an alternative name for the Charmat Method?
Cuve close
Describe the transfer method and why its becoming increasingly obsolete.
Just like the traditional method but emptying all the bottles into a pressurized tank where the wine is then filtered and re-bottled. Gyropalletes have made TM just as economical as this method and saves the step of rebottling.
How many fermentations does the ancestral method undergo?
One
What is the alternative name for late harvest wines?
Vendange Tardive
Where are late harvest wines most commonly produced?
Germany, France and Austria
What is the approximate potential alcohol level of a late harvest wine?
~13% but can go as low as 5% and as high as 15%
True or False: all late harvest wine is sweet
true
What are the classic examples of Noble Rot wines?
Sauternes, Tokaji, and Semillons in the Hunter Valley
What are the optimal ripening conditions of Botrytis cinerea?
Misty autumn mornings and warm afternoons.
What conditions can cause Botrytis to turn into grey rot?
Overcast and rainy
How does Botrytis work on the grape without compromising its integrity.
The fungus penetrates the skin of grapes with filaments, consuming water, sugar and acids. This ultimately concentrates the grape.
Why do Botrytis-affected red grapes lack colour?
The breakdown of phenolic compounds reduce the tannin in the must.
How does Botrytis affect the composition of the grape?
It increase the glycerol and the enzymes lactase and pectinase.
How long do fermentations of Botrytis-affected grape musts take?
Several months and in rare cases, years.
How is B-glucan, that can make for extremely difficult filtration of Botrytis-affected wines, be treated?
The addition of glucose enzyme that breaks it down.
Why is much more SO2 treatment necessary for Botrytis-affected wines?
The higher concentration of lactase enzyme encourages oxidation.
What are common grape varieties used in Botrytis affected wines?
Chenin Blanc, Furmint, Gewürztraminer, Semillion, Sauvignon Blanc, Riesling, Pinot Gris
Before the invent of distillation, what was a practice to prevent the spoilage of grapes?
Drying grapes
How do you dry grapes whilst still on the vine? (2 methods)
1) twisting the shoots to block the passage of water and nutrients to the grapes
2) scoring the cane to achieve the same thing
How do winemakers dry grapes after being picked already?
Placed on straw, bamboo or reeds, either indoor or outdoors, covered or uncovered. This is meant to deter mould or rot forming.
What is an example of a famous wine that uses grape drying and tends to be very rich and high in alcohol?
Amarone de Valpolicella
What is ice wine called in German? In French?
Eiswein ; Vin de glace
At what temperature can grapes generally be picked for ice wine?
7-8ºC; often picked at night for this reason
What grape varieties are good for ice wine production? What characteristics make them ideal?
Cabernet France, Vidal and Riesling; Thicked skinned to survive colder temperatures.
What level of Brix does an ice wine must need to have in Canada? Residual sugar level?
35ºBrix; 125g/L
What is the typical range of ABV for ice wines?
8-12%
What is the method used to mimic ice wine production by artificially chilling grapes?
Cryoextraction
Describe the general process of making port wine.
Grapes (Touriga Nacionel, Touriga Francesa, and Tinta Roriz) are picked when ripe at approximately 13-14% potential alcohol. Halfway through fermentation, grape brandy of 77%ABV is added to arrest fermentation. Final ABV sits around 18-20%.
What gives port the ability to age for decades?
The high phenolic content.
What are the common styles of port? What defines each?
Ruby - aged in wood, stainless steel or concrete, cheapest version, made for rapid consumption
Tawny - aged in large wooden casks, slow oxidation over time (2-40yrs), range from medium-dry to sweet
Late Bottle Vintage - barrel-aged for several years after harvest, ready to drink and similar to vintage port in flavours
Vintage - bottled less than 2.5 yrs after harvest, decision from the house based on quality of wine and vintage to name as such, kept in storage for many years before release, can age for decades if not centuries
What type of fortified wine is made in southern France from Muscat or Grenache grapes? Although its similar to port, what makes it slightly different?
Vine Doux Naturels; residual sugar must all come naturally from grapes harvested at no less than 14.5% potential alcohol. Can be either bottled young or aged oxidatively.
What is a type of fortified wine that are almost the same thing as a vin doux natural?
Mistelles (Vin de Liqueur)
How does Sherry differ from other fortified wine production?
Sherry is fermented dry before the addition of grape brandy. Base wines typically have an ABV of 11-12%. The winemaker makes a series of cuts during the pressing for the various styles.
What is the protective layer of yeast called in sherry protection that produces a lighter style?
Flor in fino sherry
Define ‘carbonic maceration’.
Grapes are placed whole-cluster in a tank where the weight of the grapes extracts a small percentage of juice which settles at the bottom of the tank. This juice, as it starts to ferment, released a protective layer of co2 in the enclosed tank, creating an anaerobic environment. This initiates intracellular fermentation. The wine is then pressed off and traditional fermentation ensues.
What are some critisicms of carbonic maceration?
A one-dimensional style as a result of the creation of ethyl cinnamate (raspberry and strawberry) and benzaldehyde (cherry). It also produces banana flavours.
What are the benefits of micro-oxygenation?
Colour stabilization, yeast growth enhancement, reduce reductive aromas and mimic barrel ageing.
What is the purpose of thermovinification?
Most commonly used for colour and tannin extraction to create fruit-forward wines but can also be used as a sterilizing agent to reduce lactase, polyphenol oxidase or Brettanomyces.
What is the alternative to thermovinification that heats the wine to almost boiling but then pushes it through a vacuum where it instantly cools the wine, cause the cells to explode and further clarified with a centrifuge?
Flash-détente.
In what circumstances, is thermovinification used on white grapes?
Over-cropped or under-ripe grapes or to inhibit enzymes from the activity in rotten grapes.
