Winemaking and Maturation Flashcards
battonage
stirring the lees
What is blanketing?
winemaking term for protecting grapes, juice, or wine, particularly from oxygen, by applying a gas, usually inert gas or sometimes CO2
What compound is to blame for the smell of oxidation as it is the first to react with Ethanol?
Acetaldehyde
Which compound is considered the main component of Volatile Acidity (VA)?
Acetic Acid
What are the main goals of acidification? (4)
1) Increase the apparent freshness and fruitiness of wine
2) Protect the wine against attack from bacteria and spoilage yeasts such as Brettanomyces
3) Enhance the effectiveness of SO2
4) Improve the color of wine. Lower pH values promote color stability by affecting the ionization of pigment compounds such as anthocyanins.
What are the two most important acids in wine and present in grapes?
Tartaric Acid and Malic Acid
What is acidulation refer to?
The process of acidification.
What are a few examples of aeration during winemaking?
Racking
Delestage
Pumping Over
How does fining and filtration affect maturation of wine?
When extreme it can hasten the rate of maturation.
How does temperature affect the maturation of wine?
Increase in temperature will hasten the maturation process but the complexity of flavor will be far less than if matured and cooler temperatures.
How does the concentration of phenolics in white wine relate to its ageability?
White wines with low levels of phenolics when bottled such as Riesling will have more potential for long aging.
What are a few techniques used for artificial aging of wine?
1) Shaking the wine to encourage effects of dissolved oxygen in the bottled wine.
2) Exposing the wine to extremes of temperature
3) Exposing the wine to radiation or ultrasonic/magnetic waves.
Describe the difference between Actual Alcoholic Strength and Potential Alcoholic Strength. What about Total alcoholic strength?
Actual is the final amount of alcohol in the wine as expressed by proof or percentage by volume.
Potential Alcoholic Strength refers to what the concentration of alcohol in a wine would be if all the sugars were converted to alcohol.
Total Alcoholic Strength refers to the sum of the actual alcoholic strength (post fermentation) + Potential Alcoholic Strength.
What techniques may be used for the reduction of alcohol in wine?
Spinning Cone Columns which are a form of low temperature distillation.
Reverse Osmosis, Electrodialysis, Evaporative Perstraction, Ultrafiltration, and Nanofiltration which are all forms of membrane separation techniques.
Humidification.
Allier is a department well-known for its oak. What AOP is located within this departement?
St-Pourçain
Why are amphora traditionally narrow at their base? What style of wine results from this? What style of wine does the concrete egg lend itself to?
To allow less lees contact with the maturing wine. This creates a more vibrant and fresh style of wine compared to egg shapes which tend to produce richer styles as a result of more lees influence.
What is the Georgian equivalent of an amphora?
Qvevri
What is a Tinaja?
Earthenware vessels commonly used in Central and Southern Spain as well as Southern Chile for fermentation and/or Maturation
How does pH or level of acidity affect the color of red wine?
The lower the pH / higher the acidity, the redder the wine will be.
The higher the pH / lower the acidity in the wine the bluer the wine will look.
pH affects the degree of ionization of anthocyanins
In 1923 what factors did Baron le Roy implement into the AOC system in addition to geographical delimitation?
Permitted Vine Varieties
Pruning
Vine Training Methods
Minimum Alcohol Strength
What drove the massive amount of fraudulent and adulterated wines to be produced in France during the first half of the 20th century?
Economic depression in the 1930s, widespread cultivation of hybrids, and a serious wine surplus increased the incentive for wine merchants to indulge in nefarious blending.
In what year was the VDQS system aboloished?
After the 2010 vintage
What technique is the catalan native Arnaud de Villeneuve credited with innovated and what style of wines resulted from this innovation?
Mutage, or the halting of fermentation by the addition of grape spirit.
Vin Doux Naturels, which became widely popular and a tradition of French Catalonia.
What is arrope and what is it used for?
Boiled down and thus concentrated grape syrup most commonly used for the sweetening of Sherry
What is ATA and what is it the result of?
Atypical ageing; a term used to identify a phenomenon found i white wine-growing regions worldwide where heat and dry conditions immediately before and after veraison resulting in extreme water stress can lead to the development of this aroma/flavor defect which can smell like moth balls, wet towel, or old furniture varnish, and may show an increased bitterness.
What is the top wine auction that takes place in Burgundy every 3rd Sunday in November and what auction house it’s official artner?
Hospices de Beaune who partners with Christie’s
What do the proceeds of Auction Napa Valley go to?
Vineyard worker healthcare and children’s education
What are the two most famous charitable wine auctions in the United States?
Auction Napa Valley
Naples Winter Wine Festival
What is the most famous wine auction that takes place in South Africa?
Niederburg Auction
What is the only way to remove Brettanomyces cells from a finished wine?
Sterile Filtration through a membrane.
What does autovinification promote and for what style of wine is it most commonly used?
Maximum extraction; most commonly used for the production of Port.
Why were the use of autovinifiers so popular in Portugal during the 1960s?
These require no outside source of power and with a labor shortage like the one faced in the 1960s and with many wineries without electricity plus an erratic power supply for those that did this was a solution to the lack of labor and energy for sophisticated pumps or presses.
How to autovinifiers work?
Pressure from a fermenting must builds up in a closed vat. This pressure forces the must up into a reservoir and then sprays back down into the vat when enough CO2 has been expelled.
What are the two most important bacteria for the production of wine?
Lactic Acid Bacteria
Acetobacter
What are the 5 attributes that must be in balance to give a wine optimal balance?
Acidity Tannins Fruit Alcohol Residual Sugar
What does the Balling scale measure?
Measures the total dissolved compounds in grape juice and therefore it’s approximate concentration of grape sugars. Very similar to the Brix scale
What style of wine is desired by winemakers who press fermenting red wines off the skins and allow a completion of fermentation in barrel? Where is this common?
A style that is softer and more approachable. This is common in Australia.
What do proponents of barrel fermentation of red wines suggest this technique promotes?
softer tannins, increased stability, and better color concentration
Why is a small degree of maturation on lees encouraged for barrel-fermented wines?
This promotes a better degree of oak tannin integration into the wine due the yeast acting on aromatic oak flavor molecules to transform them biochemically into much less aromatic substances. Additionally the yeast adsorb these aromatic compounds on to their cell walls.
What techniques can lessen the impact of oak flavor in wine?
Lighter degrees of toasting of the barrel staves.
Lees aging; yeasts will lessen the impact of oak by converting the molecules into less aromatic molecules and by adsorption of aromatic compounds into their cell walls.
Fining
What is responsible for the enhanced mouthfeel in wine following barrel fermentation? What enhances this sensation?
The rise in polysaccharides due to the contact with lees.
Batonnage will enhance this
Why do white wines that have been matured for a few months on their lees in barrel usually have a lighter color than those put into barrel after fermentation to mature?
Certain colloids are liberated during fermentation and lees contact and these will stabilize some of the phenolics extracted from the oak precipitating pigment.
Why is American oak traditionally sawed?
Because it is less porous it can be cut by sawing which maximizes the yield out of a single tree.
French Oak is more porous and thus care must be taken to split the wood in a manner that ensures the staves will be water tight.
What are the three stages of toasting and bending the staves?
Chauffage: warming the staves
Cintrage: shaping the staves
Bousinage: toasting afterwords
When are wines traditionally racked into new oak barrels?
Following fermentation prior to malolactic because malolactic fermentation occurring in barrel will promote a better integration of oak tannins into the wine.
When are nouveau wines bottled? How does this contribute to the style of these wines?
Immediately following fermentation. For this reason there tends to be a high proportion of grapes primary aromas and flavors.
What are two methods used for barrel renewal? Advantages and Disadvantage of renewal?
Shaving and retoasting the inner staves.
Removing the wine soaked part of staves with dried ice
While money is saved on purchasing of barrels, wine coming from renewed barrels rarely has the subtlety of influence that wine aged in new barrels does.
What is the ideal humidity percentage for a cellar regarding wine maturation with barrels? Why?
75%; above 75% alcohol evaporates and below it water will evaporate
What is the ideal temperature range for a barrel room for wine maturation?
50-66F
What is the volume of a barrique in Bordeaux?
225L (25 cases of wine or 300 bottles)
What is the volume of a tonneau?
900L (x4 barriques or 100 cases of wine)
What is the volume of a Burgundian pièce?
228L
What is the name of the traditional barrel in Chablis and what is its volume? What is the size of this type of barrel in the Côte d’Or?
Feuillette
132L (Chablis)
114L (Côte d’Or)
What is a quartaut? What is its volume?
Small 57L barrel often used for holding wine for the purposes of topping up.
What is the volume of a standard Cognac barrel?
350L
What is the volume of a demi-muid?
600L
What is the volume of a Mosel Fuder?
1,000L
What is the volume of a Stück? Halbstück? Doppelstück?
Stück: 1200L
Halbstück: 600L
Doppelstück: 2400L
What is the Italian synonym for barrique?
Carato
What is the traditional barrel used for the maturation of Italian Vin Santo called and what is its range of volume?
Caratelli
50-225L
What is the volume of a Gönci barrel?
136L
What is the volume of a hogshead?
300L
What are the volumes of puncheons?
132L or 450L or 500L
What is the French term for lees stirring?
Batonnage
What is the relationship between degree Baumé and potential alcohol?
The degree Baumé also is equivalent to the percentage of alcohol by volume if the wine were to be fermented to dryness.
What is blanketing?
Covering or protecting grapes, juice, or wine, particularly from oxygen, by applying a gas, usually inert gas or sometimes carbon dioxide.
What is the difference between coupage and assemblage?
Coupage and assemblage are technically the same thing meaning both blending though coupage is seen as more pejorative as it commonly refers to “cutting” a wine with inferior wines.
Assemblage refers to blending lots of fine wine for a superior product.
Why is there more bottle variation of older vintages of fine wines?
Because blending was much less common practice then as it is today. Instead of blending several vats prior to bottling, wines were often bottled from individual vats of several different fermentations.
What does “blue fining” remove from a wine?
Copper and iron
How do blush wines differ from most rosé?
They are made similar however are most often paler in color, sweet to taste, and often slightly fizzy.
What is the capacity and volume of a bonbonne/demijohn?
25L
What is bouille bordelaise, what is it composed of and what is it used for?
AKA Bordeaux mixture; composed of lime, copper sulfate, and water.
Used for the control of bacterial and fungal diseases and one of the few preparations permitted in organic and biodynamic viticulture.
What are the drawbacks of using too much Bordeaux mixture?
Can cause copper toxicity in soil.
How is wine quality affected for red wines that are influenced by botrytis?
The wines won’t have as deep of color and will develop off flavors of mold.
Why are higher levels of SO2 required at bottling for the production of botrytized wines?
The enzyme laccase is produced by the botrytis fungus and this will increase the risk of oxidation. Also the chemical composition of botrytized wine more readily binds with SO2 so more is needed than for other wines.
Before what year was selling wine in bottle illegal in Britain?
Before 1860
What does feuille morte refer to?
Refers to the yellow-green color of wine bottles used for the bottling of white Burgundy. Means “dead leaf” in French.
What is bottle sickness and what are two reasons a bottle may display this? How is this alleviated?
Refers to the unpleasant and increasingly rare smell apparent in a wine immediately on opening which can happen as a result of high levels of dissolved oxygen in the wine as a result of racking or other agitating procedures prior to bottling or can be caused as a result of a lack of oxygen (reduction) which can lead to the development of sulfur like aromas.
Can be alleviated by decanting .
What is the volume of a Marie-Jeanne wine bottle?
2.25L or 3 standard bottles
What is a Methuselah called in Bordeaux? What is its volume?
An Impériale; 6L or 8 bottles
What is a double magnum called in Champagne? What is its volume?
Jeroboam; 3L
What is the volume difference between a Jeroboam from Bordeaux and a Jeroboam from Champagne?
Jero from Bordeaux is 4.5L or 6 bottles
Jero from Champagne is 3L or 4 bottles
What is the volume of a clavelin?
62cl
What is the name for a wine bottle holding 24 bottles and 34 bottles respectively?
Melchior - 24 bottles
Sovereign - 34 bottles
If a wine is bouchoné, what is it?
Corked (TCA)
What strain of Brettanomyces is most commonly found in wine and beer?
Brettanomyces bruxellensis
What is the most important substrate necessary for a Brettanomyces takeover?
Residual sugar
Which two methods can eliminate Brettanomyces at the time of bottling?
Sterile filtration and/or the use of dimethyl dicarbonate (DMDC)
What is the capacity of a botta chica? Where is this most commonly used?
500L; used in the Jerez region for shipping sherry.
What does the process of watering back entail?
The process of diluting prefermented juice or grape must for the purposes of reducing alcohol levels in the resulting wine following fermentation.
What is illegal in the US unlike Europe in regards to sulfite addition?
The US does not allow any addition of sulfites which would raise the free SO2 level over 10 parts per million.
What is the biggest drawback of cans for wine storage?
Cans are lacquered on the inside but if there is a pinhole or small breach in this layer, the wine will react with the metal creating foul smelling Hydrogen disulfide and the wine may turn black.
The wine fault casse refers to what?
An excess of iron, copper, protein, or Tartaric Acid precipitation.
What is a girasol used for?
A girasol is a gyropalette and is used for the automted remuage of hundreds of bottles of traditional method sparkling wine often for the production of Cava
What is Verbesserung?
German for Chaptalization.
What does enrichment refer to?
Refers to the addition of sugar, grape must, grape concentrate, and rectified concentrated grape must (RCGM) in order to increase a wine’s alcoholic strength.
What is the most desired effect winemakers are looking for by chaptalization?
Higher complexity of flavor and better texture of wine, not to boost alcohol as its most often believed. Flavor and texture are improved due to chaptalization extending the length of fermentation.
What is charcoal used for in winemaking?
Used to remove color and off flavors caused by botrytis or sour rot. Also used to absorb the pigment polymers responsible for amber or brown colors in the manufacture of pale cream sherry.
What is the difference between clarification and stabilization?
Stabilization is a form of clarification but refers to the removal of substances such as excessive tartrates, pectins and gums, some proteins, and small numbers of micro-organisms such as yeast and bacteria that ARE NOT VISIBLE to the unaided eye. No further clarification is needed following this.
What is débourbage?
Debourbage is the french term for settling, or the process of holding liquid, wine or must, in a tank and allowing the solids to settle to the bottom. This is a form of clarification.
What are 5 methods used for Clarification?
Settling (debourbage) Filtration Centrifugation Fining Flotation
Red wines are not commonly clarified before fermentation because the skins are fermented with the juice in order to provide color and flavor. Be that as it may pectin-splitting enzymes are sometimes added to red must prior to fermentation. Why?
To aid subsequent clarification and increase the eventual yield of free-run wine.
What is ropiness?
A wine fault where an excess of polysaccharide is produced by malolactic bacteria leaving a stringy almost slimy residue in the wine.
What are the 3 top goals of cofermentation?
Lift a wine’s floral aromas
Enhance its texture
Improve the brilliance and intensity of the wine’s color
What does “collage” refer to?
Collage refers to the process of fining
What are 5 factors that can influence the color of red wine?
Berry Size
Homogeneity of Ripeness
Length and Temperature of Maceration
Techniques influencing Extraction such as Pumpovers and Punchdowns
Thickness of Grape Skins
Why do red wines show more brick red pigments with age?
Brick red pigments are a more stable form of pigmented tannins and remain in the wine for a longer period of time.
The purple pigmented tannins that are very present in a wine’s youth are less stable with age and combine to form large molecules in the wine, falling out of solution to become sediment.
How does barrel maturation influence pigmentation in wine?
Barrel maturation increases the stability of pigments in wine by introducing modest amounts of oxygen which promote the formation of stable pigmented tannins.
How does free sulphur dioxide in wines affect red wine color?
Free sulphur dioxide in wine has a bleaching effect on pigmented tannins and so wines with more free SO2 will present paler than wines with less free SO2.
This is more obvious in youth as the bleaching effects on the wine’s color become less effective with age.
How does free SO2 affect bouquet development of tertiary flavors with age?
It slows the development by disrupting the chemical interactions between wine phenolics and other wine constituents responsible for generating the wine’s bouquet.
In most white wine production, why is extended maceration avoided prior to and during fermentation?
This will extract more phenolic compounds that when react with oxygen will promote premature oxidation and browning of the wine.
How does lees contact influence the color of white wine?
Lees contact will produce wines with paler color due to darker pigments in the wine being absorbed by the lees.
What is the major disadvantage of using epoxy -lined concrete vats for fermentation?
Very little oxygen exchange which affects tannin development. It’s for this reason that many choose unlined concrete vats.
What are the three main acids found in grapes?
Tartaric (most present)
Malic
Citric
How does acidity in wine affect its texture?
Higher acidity (lower pH) gives the wine a perceived harder more tannic structure.
Lower acidity (higher pH) gives the wine a soapy expression.
Between what pH levels is most wine?
3-4
What are two main sources of catechins in wine and what aspect of flavor are they most correlated with?
Stems and seeds, though sometimes from skins.
Associated most closely with bitterness in wine.
Rose, lychee, spicy, floral, orange, peach, eucalyptus, and pine are all common descriptors in wines with higher levels of what compound? What are a few grapes that are reputable for having these?
Monoterpenes
Vigonier, Gewurztraminer, Muscat
Black and white pepper found in wines is common in grapes with a high percentage of what compounds? What are a couple of grapes that contain these?
Sequesterpenes and in specific Rotundone.
Syrah, Schioppettino and Gruner Veltliner
The impact and pungency of black pepper or Rotundone wanes with increased exposure to what?
Warm and Sunny Climates
This is why Australian Shiraz, while being the same grape as its Northern Syrah counterparts typically shows less overt peppery notes when compared to its French cousins.
TDN (Trimethyl dihyrdonapthalene) is responsible for what aromas in wine? What will increase its concentration in the grapes?
Petrol or Kerosene aromas.
Light exposure increases the concentration of this.
What are two techniques for tempering the impact of pyrazines in wine?
Light exposure following veraison (hang time) and use of New Oak in the production of the wine will temper the impact of pyrazines in the finished wine.
Which grape varietals are reputable for having a higher concentration of thiols? What are some aromas and flavors associated with these compounds?
Bordeaux varietals
Passionfruit, guava, cassis,
What are two additions to grapes or grape must prior to fermentation to prevent oxidation?
SO2 and dry ice
What is the name of the enzyme produced in botrytized grapes that resists the effects of SO2?
Laccase
What two signature aromas are imparted to wine that is produced from botrityzed grapes?
Ginger and Saffron
Name a few dry wines in which the presence of botrytized grapes is common?
Austrian Smaragd Riesling and Gruner
Savennierres
Some wines from Alsace
White wines that seek to be produced with minimal skin contact like those used for sparkling wine production are pressed how?
Whole-cluster pressed as this reduces the number of grapes in the vat and promotes quicker pressing improving juice yield and aiding clarification.
What is the difference in style of the juice that is pressed from destemmed and crushed fruit compared to whole cluster pressed?
Destemmed and crushed tends to be more extracted and textured and is often but not always considered to be used for the production of lesser quality wine.
Whole-Cluster Pressed produces clearer juice with fewer skin-derived compounds including phenolics that may cause bitterness. Wines produced from this juice tend to be clean, bright, and delicate in style.
What are the 4 different types of fermentation in regards to destemming or not and crushing or not?
Traditional Fermentation: Destemmed and crushed.
Whole Berry Fermentation: Destemmed but not crushed.
Fermentation with Stems: Not Destemmed but Crushed
Whole-Cluster Fermentation: Not Destemmed or Crushed
Does Carbonic Maceration require yeast or bacteria?
No, this is an intracellular fermentation mediated by the grapes’ own enzymes and occurs in the absence of oxygen.
How much abv does Carbonic Maceration produce prior to the active grape enzymes being denatured and halting fermentation?
2%
What are 5 aromas and flavors imparted to a wine through Carbonic Maceration?
Strawberry Bananna Bubble Gum Kirsch Pear Drop
What do stems contribute to finished wine in a whole-cluster fermentation?
Stems increase the concentration of catechins and potassium in the wine thus producing that is typically more tannic with a higher pH (lower acid) and lower alcohol. Additionally the stems will absorb pigment so the color of wines that are produced with partial or full whole clusters will often be lighter in color as a result.
For what purpose are pectolitic enzymes used in the production of wine?
Used for the aiding of extraction of color, tannin, and flavor during fermentation and at pressing as they break down the skins of grapes.
What white grapes are commonly allowed skin contact prior to fermentation?
Aromatic grapes such as Muscat and Gewurztraminer but not too much as their skins often can impart bitterness if allowed to macerate for too long.
What are three methods for producing rosé wine?
Direct pressing of red grapes.
Short maceration prior to fermentation (saignée)
Blending red and white wines (Champagne)
What is cold soak and for what purposes is it used?
Cold soak is holding uninocculated grape must at a cold temperature prior to fermentation allowing fruit enzymes to begin extraction of color and flavor compounds from the skins prior to fermentation.
This may also be used to allow native yeast populations to grow as the colder temperatures favor them over Saccharomyces at cold temperatures.
This can also be the byproduct of a busy winery and not having enough labor to manage the fermentation of the must so cold soak will allow the must to be kept at a relatively stable condition until someone can manage its fermentation.
For what styles of wine is thermovinification and flash détente useful for?
Useful for creating acceptable wines form lower quality or compromised fruit. The higher temperatures for instance promote a quick extraction that avoids the unwanted flavors that can be contributed by pyrazines or smoke taint in fruit as these require longer periods of extraction to remove from skins.
These are also useful for minimizing the oxidative impact of botrytis in grapes as the higher temperatures denature the enzymes laccase found in high concentrations in affected grapes.
What is the difference between thermovinification and flash détente?
Theromovinification heats the must up to 140-180 degrees for 30 mins to 24 hours and then is pressed directly after heating and fermented off skins.
Flash Détente rapidly heats the must to near boiling temperatures 185 degrees and then rapidly cools this in a vacuum. Fruit treated in this manner resembles jam following the process. Must is allowed to settle over night then is drained and pressed allowing a fermentation to take place off of the skins.
What style of wine is produced from thermovinification and flash détente?
Fruity, accessible wines with jammy flavors and less natural tannin extracted.
What is another name for the Russian method of sparkling wine production and how does it work?
Continuous Method
Base wine is pumped into a series of pressurized tanks along with liqueur de tirage and a secondary fermentation is allowed to commence within the tanks. This passes from one tank to another which sometimes contains wood chips that can give the wine a toasty flavor. Along with this accumulated lees that result from continuous fermentation will impart autolytic brioche and toast flavors to the wine.
What is the French word for a cooperage?
Tonnellerie
What percentage of France’s IGP wine is produced by Cooperatives?
70%
What is a top cooperative in Champagne?
Union
What is a top cooperative in Chablis?
La Chablisienne
What is a top cooperative in the Rhone Valley?
Tain l’Hermitage
What is diam cork, how is it treated and what risk is it said to mitigate?
Diam Cork is a patented cork that is the product of grinding down cork particles, treating them with supercritical CO2 to purge them from TCA and then reassembled using food grade binding agents or agents that are completely plant based plus the combination of a beeswax emulsion.
This cork is said to eliminate TCA risk
What can a misshapen and elongated cork pulled from a bottle of nv sparkling wine indicate?
This would indicate significant post disgorgment aging prior to the point of opening.
What is cork taint or TCA exactly?
Metabolic products of fungi which are naturally present in cork or which have grown in cork at various processing stages
What is a method of fining useful for removing harsh tannins from press wine?
Fining with egg whites
What is débourbage?
Clarification of freshly pressed grape must by letting it chill overnight allowing solids (bourbes) to settle overnight allowing for a racking the following day. This is most common with white wine must and reduces the need for filtration.
What are three techniques for prefermentation clarification of pressed grape must?
Débourbage/Cold Settling
Filtration/Centrifugation
Flotation
What is flotation?
Prefermentation clarification technique where gas is pulsed through the grape must causing bourbes to float to the top where they are skimmed off.
How does Bentonite aid in clarification prior to fermentation?
Bentonite, a naturally occurring clay, can remove grape solids, yeasts, bacteria, proteins, and pectin by attracting them through electrostatic forces. It is not soluble into grape must and can be removed during racking.
What technique is sometimes avoided to enhance the viscosity of wine and concentration of volatile thiols in the wine that give wine a flinty characteristic or positive reductive notes?
Clarification prior to fermentation or allowing the solids (bourbes) to remain in the must following pressing.
What are three causes of low sugar levels in fruit at harvest time?
Unripe Fruit
Rain at Harvest Time
Vine Viruses present in the Vineyard
What technique is used to remove water from grape must to increase the concentration of potential alcohol?
Reverse Osmosis
Though a frowned upon practice, water can be added to grape must for the purpose of lowering alcohol. What are a couple of methods for doing this?
Irrigating just before harvest to dilute grapes slightly.
Addition before fermentation following pressing which actually increases the extraction capacity of the fermenting must.
Addition following fermentation which only dilutes the finished product.
What acid can be added to fermenting grape must to enhance the buttery characteristics of a particular ferment?
Citric Acid; this is converted into diacetyl by lactic acid bacteria which smells like popcorn butter.
What improvements can be achieved by adding tannin to grape must?
Stabilize the color
Improve a wine’s tannin structure
Help mitigate the impact of off flavors such as smoke taint and reduce the oxidative impact of botrytis.
What are the two most important strains of yeast for wine ferementation? Which fermentations is each linked to?
Saccharomyces cerevisae (alcoholic fermentation) Oenoccucus oeni (malolactic fermentation)
For what reason does Brettanomyces in a finished wine often become more prominent with age?
Brettanomyces can ferment sugars that Saccharomyces cannot so any sugars in the finished wine are often vulnerable to metabolization by Brett and thus the impact of this yeast grows with age.
How can Brett be removed from wine?
Prevention rather than treatment is the best remedy as once Brett metabolizes in the wine the impact is difficult to mitigate. The best forms of treatment if Brett is detected is to use sterile filtration to remove these yeast cells. Otherwise careful hygiene in the vineyard is best to mitigate the impact of Brett.
How can volatile acidity be removed from wine?
Reverse Osmosis
Removal of the responsible microbe by filtration and blending with a low VA wine to mitigate the impact.
What can increase the concentration of VA in wine?
Poor hygiene in the winery and not topping up the wine during maturation exposing the finished wine to oxygen.
In addition to alcohol and lactic acid what do microbes in fermenting wine produce?
Esters, aldehydes, and sulfur containing compounds.
What are two drawbacks of native yeast fermentations?
Unpredictable rate of fermentation with stuck fermentations not uncommon.
Strong/off-putting signature flavors in some strains.
What is “pied de cuve”?
This is the winemaking equivalent of a sourdough starter culture. It is commonly used by winemakers that want to use the wild yeast from the vineyard for fermentation. It consists of a portion of yeast-rich, already fermenting grape must.
What will low levels of nitrogen in fermenting grape must result in?
Reductive H2S that can smell like rotten eggs and can also lead to stuck fermentations.
What is Diammonium Phosphate (DAP) used for in the winery?
Adjusting nitrogen deficient grape must for the purposes of avoiding stuck fermentation and reduction. Use of this can also result in the production of complex compounds and esters that make wines taste more fruity and floral.
What is foulage?
Crushing the grapes.
What is égrappage?
Destemming
What is a cuve? Cuverie? Cuvaison?
Cuve is the French term for vat which can be made from wood, concrete, or most likely stainless steel.
Cuverie is the French term for the place where fermentation takes place.
Cuvaison is the French term for maceration during fermentation
What are three methods for deacidifying a wine?
Allowing a malolactic conversion.
Adding Calcium Carbonate or Chalk which will precipitate excessive acid into tartrates that can be filtered out.
Double Salt Deacidification
Reverse Osmosis
Electrodialysis
What is the preferred method for removing alcohol in wine? How does this work and why is it the preferred method?
Vacuum Distillation
This reduces the boiling point of alcohol to room temperature allowing alcohol to boil off while preserving the non volatile components of the wine such as minerals, acids, phenolics, sugars, and vitamins are fully preserved.
By avoiding high temperatures, there is no risk of cooked flavors.
What is the main drawback with the integrity of a wine when alcohol is removed?
Alcohol acts to stabilize the wine and when it is removed the wine’s integrity becomes much more fragile. Additionally this can be expensive.
What are three methods for removing alcohol in wine?
Vacuum distillation
Reverse Osmosis
Spinning Cone Column
Dekkera is synonymous with what?
Brettanomyces
What is délestage?
This is a racking technique where fermenting wine is drained from a fermenting vessel into another tank and the cap remaining is allowed to drain for a couple of hours. Following this period the wine is pumped back over the top of the cap.
Égrappage and Éraflage are also known as what?
Destemming
What effects does destemming have on the fermentation of wine?
Fermentation will be likely slower and cooler since including stems will increase oxygen in the tank and thus the rate of reaction and heat.
Increases the color and alcoholic strength
Why do some producers in Burgundy and Rhone believe in retaining a certain proportion of the stems?
To add structure, influence color, and add mid palate weight to improve texture while additionally easing the drainage of juice through the cap during maceration of red wines and the pressing for white wines.
For what purpose is datomaceous earth (DE) used?
Used for filtration
What is dimethyl dicarbonate (DMDC) used for?
Used to eliminate Brettanomyces growth in bottle. It works by deactivating enzymes in the spoilage yeast.
How can the growth of Brettanomyces in bottle be inhibited?
By bottling with the addition of DMDC (dimethyl dicarbonate) which deactivates the active enzymes of this spoilage yeast.
Between what range of temperatures is yeast active?
45-95 F; below they are inactive and above they die
Between what temperatures are most white wine fermentations carried out? Why are white wines typically fermented at cooler temperatures than red wine fermentations?
Between 45-65F; temps on the cooler end of the spectrum favor crisp styles where the warmer favors riper, fruitier, and more floral styles.
White wine fermentations are typically fermented at cooler temperatures to preserve volatile compounds that impact fruit and floral aromas and also extraction is not necessary so warmer fermentations are typically more for red wine fermentation where extraction is key.
Why do barrel fermented wines typically have better integration of oak than wines fermented in stainless or neutral vessels and allowed to age in new oak?
Anthocyanins react with oak tannins during barrel fermentation creating stable color and facilitate better integration through this. This would not happen to the same extent with fermentation in stainless or neutral vessel followed by aging in new oak.
What are the three most common techniques for cap management during fermentation?
Remontage/Pumpover
Pigeage/Punchdown
Délestage/Rack and Return
At what point of the fermentation are most anthocyanins extracted? What about tannins?
Anthocyanins are more soluble in water and thus are mostly extracted at early stages of fermentation and prior to.
Tannins are more soluble in alcohol and thus are more extracted at later stages of fermentation.
What are three methods for arresting fermentation?
Lowering the temperature of fermentation combined with the addition of sulfur.
Filtration or centrifugation
Fortification/Mutage
How is malolactic fermentation blocked following alcoholic fermentation if desired?
Addition of sulfur dioxide (SO2) will inhibit this.
Addition of Lysozyme which is an enzyme that destroys LAB
Filtration
What 4 conditions can inhibit malolactic fermentation?
Low temperatures
Low pH (below 3.2)
Sulfites
High Alcohol (above 14.5%)
Why do winemakers prefer to carry out MLF after alcohol fermentation?
Reduces competition of LAB with Yeasts for sugar promoting a more efficient fermentation reducing the risk of stuck fermentations along the way.
Reduces the risk of high VA levels in the finished wine as LAB can convert sugar into this.
Why is MLF delayed sometimes following primary alcoholic fermenation?
Vital color stabilization reactions following primary fermentation are interrupted and sometimes prevented by LAB if MLF is not delayed.
What factors of aging influence and shape a wine’s maturation following fermentation?
Aging vessel along with cellar practices such as stirring, topping, racking, and sulfur additions.
What are a few of the benefits of aging a wine on the lees?
The lees will continue to protect the wine from oxidation as oxygen is consumed by them.
Why is some oxidation during aging important for the maturation of red wines?
Stabilizes color and softens the tannins by facilitating the polymerization of phenolic compounds.
Why is red wine more resistant to oxidation of aromas and flavors than white wine?
Red wine has a much higher concentration of antioxidant phenolic compounds (pigment and tannin) due to their extraction from maceration which react with oxygen more readily. These reactions consume the oxygen and thus protect the wine’s aroma and flavor compounds from oxidation more readily than white wines.
What is mox?
Mox is short for micro-oxygenation which is a technique used to introduce a slow dose of oxygen over time. For wines aged in tank, this technique mimics the oxidative benefits of barrel aging and is seen as a more economic alternative.
It is also said to soften tannins, fix color, and reduce vegetal/herbaceous/reductive aromas in aging wine.
What is cliquage?
Cliquage is a technique similar to micro-ox but uses a larger amount of oxygen introduction to aging wine is meant to simulate the labor-intensive practice of racking.
Micro-oxidation is typically used on what kind of grape varietals during the aging process?
The most tannic such as Tannat, Nebbiolo, etc.
In what appellation was micro oxidation invented and for what grape?
Madiran AOP for wines produced from Tannat.
What are the main benefits of oak aging?
Addition of flavor and tannin to boost complexity and structure.
Concentration of the wine through evaporation.
Slow oxidation which gives a wine a softer and more mature profile.
What are 5 types of oak used for the maturation of wine?
White Oak Acacia Eucalyptus Redwood Chestnut
What are the costs prices associated with a new American Oak barrel vs a new French Oak barrel?
American Oak will cost around $450
French Oak will cost around $900
What are the species of tree commonly used for French Oak? American Oak?
Quercus suber and Quercus petraea are used for French Oak
Quercus alba used for American
What are 6 forests in France that quality oak for cooperages are sourced?
Vosges Bertranges Nevers Tronçais Allier Limousin
How does a barrel with higher toast impact the wine aged in it?
The barrel will provide less oak and lactones and provide more smoky, grilled, and toasty aromas.
What is one technique for barrel production that will give toasty flavors to wine with less tannins?
Toasting the barrel heads
Which type of barrels contribute more tannin to wine, French or American?
French oak will contribute almost twice the amount of wood tannin than American produced with a similar degree of seasoning and toasting.
How much more expensive is French oak than American oak?
2-4 times more expensive
When happens to wine aging in barrel when the humidity rises above 70%? Falls below 70%
When the humidity rises above 70% alcohol will evaporate at a quicker rate than water and thus the alcohol level of the wine will decrease over time.
When the humidity falls below 70% water will evaporate at a quicker rate than alcohol and thus the alcohol level will rise
Why do crystals sometimes form during maturation of wine?
Evaporation either in barrel or bottle can result in the concentration of acids that become insoluble and fall out solution as precipitation.
What does ouillage refer to and what is its purpose?
Topping up; to replace wine that has evaporated during maturation in barrel. This will prevent spoilage and oxidation during the aging process.
Term for the product of evaporation?
Ullage
What are two styles of wine that are aged biologically under a layer of Saccharomyces film?
Fino Sherry and Vin Jaune
What are some aromas associated with acetaldehyde, a common biproduct of oxidation in wine?
Bruised apple, nutty
Why do wines with higher levels of RS and/or lees require more SO2 addition than dry wines with no lees?
More SO2 is required because a greater proportion of SO2 becomes bound in wines with more RS and/or lees.
At what stages of fermentation is SO2 added? Why at each stage?
Prior to fermentation for the purpose of denaturing oxidation enzymes and preventing microbial spoilage.
During fermentation for the purpose of arresting it.
Just following to prevent MLF
During bottling to mitigate exposure of oxygen at the time of enclosure.
Why do bottles of German Riesling with RS sometimes have crystals in the bottle?
Higher levels of sulfur are added to these bottles to keep them stable and often it is added in the form of KMBS or Potassium metabisulfate which increases the pH of the wine and facilitates crystalization. This can also happen if the wine has not been cold stabilized.
What factors can allow for the low usage of sulfur?
Use of Healthy Fruit
Low pH and sugar levels in the wine
Clean Cellar Practices
Minimal oxygen exposure
What does soutirage refer to?
Racking
Gros lees are composed mostly of what?
Yeast, grape solids, and tartrate crystals
What is the purpose of racking/soutirage? When can this occur (7)?
To remove wine from gros lees for the purpose of clarification and to introduce oxygen to moderate the effects of aging.
This occurs prior to fermentation after debourbage.
After primary fermentation.
After MLF
During blending
After fining to remove fining agents and before filtration
After cold stabilization to remove tartrates.
During maturation prior to bottling.
What is soutirage à l’esquives?
Older less modern form of racking where the wine is racked by draining through a valve on the face of the barrel wherein the barrel is tilted to decant the wine off of the solids.
What are several tannin fining agents?
Casein (milk) Albumin (egg whites) Isinglass (fish swim bladder) Gelatin (tendons and muscle) PVPP Nylon
What specific purposes is Bentonite used for?
Used to make a finished wine heat stable by binding to and precipitating out proteins that would otherwise become insoluble in the wine with a slight change in temperature during bottle age.
Also used at the juice stage for clarification prior to fermentation.
Which fining agent is best for the fining and removal of reductive aromas from a finished wine?
Copper usually through the addition of Copper Sulfate
Wines with a higher amount of malic acid and/or residual sugar often go through what type of filtration process?
Sterile filtration or removal of yeast and bacteria; to prevent refermentation in bottle
What are a few wine flaws that can be removed via reverse osmosis?
Smoke Taint
Ladybug Taint
VA
How does cold stabilization work?
Wine is chilled and at cooler temperatures, tartrates become insoluble in excess and fall to the bottom of the wine as crystals. The wine can be racked off of these.
What is the Scorpion test used for?
Used to identify Brettanomyces and/or spoilage bacteria.
For what purpose is lysozyme added to wine?
To prevent MLF
What is Chitosan and for what purpose is it used for?
Chitosan is a positively charged fining agent derived from the exoskeleton of crustaceans that is used to remove yeast, including Brettanomyces
What is the drawback of using Scorbic Acid for inhibiting the growth of yeast?
It can be converted by lactic acid bacteria into a floral-scented compound responsible for so-called geranium taint.
What is DMDC used for and what is its other name?
Used to make wine microbial stable and while it is very toxic to humans it breaks down rapidly once added to wine into harmless compounds.
AKA Velcorin
What is the most commonly used microbial stability agent used?
SO2
What is bottle shock?
Phenomenon where wines shut down aromatically just following bottling.
What are shiners?
Shiners are wines that have been bottled without labels that are sold off to another location for labeling.
Vin d’égouttage is wine produced from what?
Free run juice
How does the period of drying time change depending on grapes/climate?
Warmer climates produce riper grapes and these need less time to dry, sometimes only three weeks.
Cooler climates will produce grapes that require a longer drying period, sometimes up to a few months.
What are two examples of using the lees of a passito fermentation to enrich the must of another wine?
Governo in Tuscany
Ripasso in Veneto
Passito wines, due to their high sugar content are notorious for having high levels of what?
Volatile Acidity
What is the primary role of egg whites in the fining process?
To absorb and remove harsh/bitter tannins in red wine.
How does electrodialysis work and what is it used for?
This is a filtration technique which allows the removal of selected ions for the purpose of stabilizing a wine. It is considered a faster alternative to cold stabilization and filters out potassium, tartrates, and bitartrates.
This technique can also be used to lower the pH of a wine without acidification.
For what reasons may a vigneron choose to plant at higher elevation?
Mitigate warm temperatures by planting higher where its cooler.
To plant on soils that are perhaps less fertile and thus more ideal for viticulture.
Increased solar radiation to increase stimulation of phenolic synthesis
What is the goal of enrichment/amelioration?
To increase the alcoholic strength of the resulting wine through the addition of sugar (chaptalization), grape must, concentrated grape must, and rectified concentrated grape must
What are the two most common sources of sugar for enrichment?
Sucrose
Beet sugar or Cane sugar
What is a subtractive method for enriching grape must?
Reverse osmosis to remove water
What do Glycosidases contribute to a fermenting must?
These will assist in releasing aromatic compounds and increase aromatic intensity.
What is lysozyme used for in wine production?
To prevent malolactic fermentation by breaking down malolactic bacteria cell walls
What reaction creates ethyl acetate?
Acetic acid + ethanol
What can haze in a finished wine indicate?
The growth of micro-organisms yeast or bacteria, heat unstable proteins and/or heavy metal contamination.
Why are off-dry white wines often bottled with a little CO2?
To enhance the refreshing taste.
What are three iconic wines or styles that can show higher than normal volatility?
Vega Sicilia
Penfolds Grange
Port
Mousiness in wines said to be produced by what?
Lactic Acid Bacteria
Ullage is generally not desired, however in what kind of red wines is this sometimes beneficial?
Extremely tannic wines can benefit from higher than average ullage as the oxygen will assist in softening out the tannin profile of the wine.
Flor is what strain of yeast?
Saccharomyces cerevisiae
What are three styles of wine that benefit from a film forming yeast during production?
Biologically-aged Sherries such as Manzanilla, Fino, and Amontillado
Vin Jaune
Szamorodni Szaraz Tokaji
Mycoderma refers to what?
A film-forming yeast
What are the two main objectives of fining?
To clarify and stabilize the wine.
In what appellation of the Southern Rhone is flash détente permitted?
Côtes du Rhone
What is flash detente and how does it work?
The technique of enhancing extraction of grapes by heating them up to around 200F and then immediately putting them under vacuum.
What is flotation?
Must clarification technique that operates under the idea that grape solids will adhere to rising bubbles. The big advantage of this technique is that the resultant wine is more resistant to oxidation. This is typically used in large wineries where the process can run continuously.
What is the traditional barrel used in the Mosel region? Rhine regions?
Fuder (1000L) is the traditional barrel of the Mosel
Stück (1200L) is the more traditional barrel of the Rhine Regions.
gallic acid measures what?
Tannin
What is geosmin and in what kind of wines may you find it?
geosmin is a compound strongly associated with a strong earthy or muddy aroma that is a by-product of soil bacteria and usually associated with wine faults.
Found in red and white wines made with rotten grapes, it is also present in some wines with cork taint.
How does the tightness of grain influence porosity and flavor impact of a barrel?
Counterintuitively, the tighter the grain the more porous the barrel and the more impact on flavor the barrel will have.
What is Pommace?
the solids including the stems, skins, seeds, and pulp left over after the pressing process.
How is grape concentrate produced without carmelized flavors?
It may be boiled at lower temperatures under a vacuum.
What vinification technique may assist with reducing the herbaceousness of fermenting unripe fruit?
Micro oxygenation
What is a secateur?
Pruning shears
What does humidification refer to?
The addition of water to wine or must to reduce alcoholic strength in the finished wine.
During what stage of fermentation is H2S most likely to accumulate and why? How can this be mitigated during fermentation? How can it be mitigated prior to harvest?
During the vigorous stage of fermentation as this is when nitrogen levels in fermenting must can drop rapidly lending favorable conditions for H2S to form.
The addition of DAP and the selection of the right yeast strain for fermentation will mitigate this.
Ceasing the use of sulfur applications to the vineyard several weeks prior to harvest can also help.
What are some attributes that cold maceration before fermentation lends to a wine?
Extracts more color and less astringent tannin.
Enhances aromatics and makes organic acids more stable
Who is Patrick Ducourneau?
Inventor of microbullage (Madiran)
In what AOP was Microbullage invented?
Madiran AOP for the softening of Tannat’s tannins.
What is the difference between microbullage and cliquage?
Microbullage is adding micro-oxygenation during fermentation and mimics oxidative benefits of barrel.
Cliquage is a larger dose of oxygen introduced later in barrel or finshed wine. This is meant to replace labor intensive soutirage/racking
Which is meant to be an alternative to racking/soutirage, microbullage or cliquage?
Cliquage
What is the difference between Cuvaison and Cuvage?
Cuvaison is the maceration of grapes during fermentation.
Cuvage is maceration following fermentation.
Why would a producer choose to use spinning cones during fermentation?
Spinning cones are used for fractionation and for the end goal of reducing alcohol.
What is vin de goutte?
Free run juice from the press
What is the name of the tool used to measure sugar content in fermenting must?
Hydrometer
Between depth filtration and surface filtration which is more invasive?
Surface
What are two winemaking techniques to prevent VA?
Top up frequently to avoid oxygen access for VA bacteria and adding SO2 will prevent VA
