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129 Cards in this Set
- Front
- Back
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What are the two keys stages of berry development?
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Fruit set, Verasion
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What are the two key sugars in grapes?
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Glucose and Fructose
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What happens to the sugar concentrations when Botrytis Cinerea occurs?
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Ration of fructose is greater than glucose
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Name a country in which the following measurements of sugar are used: Brix, Baum, Oechsle?
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Brix (US), Baum (France), Oechsle (Germany)
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If the Brix measurement is 24B and the desnsity is 1.12, what is the % of alcohol if the wine is fermented completely?
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% alcohol = 0.58 x (Brix - 2.1) x density
0.58 x (24 - 2.1) x 1.12 = 14.22% |
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What are the main acids in grapes?
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Tartaric and Malic
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What acid is commonly found in grapes that have been infected with Botrytis Cinerea?
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Citric
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What acid usually is detected in the evolution or finish of a wine that has a slightly bitter taste and aids in swallowing food?
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Lactic
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What is the overall weight composition of grape clusters?
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75% must; 16% skins; 4% seeds, 5% stems
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What fractions of grape weight is in the free run and press run if you are making white wine?
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60% free run; 70% press run
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What fraction if grape weight is in the free run and press run if you are making red wine?
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60% free run; 65% press run
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At what time should all chemical use be stopped to insure that no chemical flavors are carried into the wine?
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around the time of verasion (when the grapes change colors)
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At what time should irrigation be stopped if dry farming techniques are being used?
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at least a month before harvest
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At what time should leaf removal occur to keep berry clusters from being over-shadowed?
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start at verasion and repeat when necessary
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What is a major advantage and disadvantage to mechanical harvesting?
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advantage - allows picking grapes at night when temperature is low; disadvantage - major portion of skins are broken
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What is tonnage per acre that is the break-even point for doing mechanical harvesting?
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Damage to berries is minimal
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When is the best time of day to hand harvest?
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Very early morning until noon
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What is the purpose of de-stemming?
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Separate stems from must
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What negative flavors can be found in wines that weren't sufficiently de-stemmed?
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Hard-veggie or green flavor
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What is the purpose of the crush?
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Break skins to allow release of juice
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Since the fermentation of white wine is done without skins, what two methods are employed to prepare the white grape must for fermentation?
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Destemming / crushing followed by press or direct pressing of whole clusters
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What technique is commonly used to prepare white grapes for fermentation in the production of sparkling wine?
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pressing whole cluster without destemming or crushing
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What technique is commonly used to prepare Muscat or Semillon clusters for fermentation?
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Pressing whole cluster
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What term is used to describe the absorption of oxygen that is common in white wine making?
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oxidation
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Below what temperature F should white wine must be kept to avoid the absorption of oxygen?
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< 10 degrees C
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The skins being removed from the production of rose wines can be added to the must of red wine, during fermentation, to enhance what characteristics of the wine?
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color, tannin and body
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What fraction (as a percentage range) of the total must is often left with stems in the production of red wines?
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20% - 40%
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Why is SO2 (sulfor dioxide) added to wine in modern winemaking?
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protect against oxidation, protect against microbial spoilage
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What are two types of oxidation that occur in wine making and when do they occur?
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enzyamatic - in must before fermentation; chemical - during processing and in bottling
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SO2 is added to barrel maintenance in order to protect it against what two agents?
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mold; all kinds of wine spoilage (micro-organism)
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What 3 major components of wine are stored in skin of the grapes? These compounds are correctly called what?
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varietal flavor, color, and tannin compounds
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What chemical structure is responsible for the "dry" feeling, or astringency of red wine?
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OH (hydroxyl); tannins
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What group of compounds give wine color?
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anthocyanins (flavonoid pigments found in red/purplish fruits and vegetables)
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Polymeric forms of anthocyanins and benzoic acid derivates are the basis for what common group of compounds in wine?
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tannins
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Flavors in wine are basically derived from what acid?
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cinnamic acid
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What is the length of skin contact in white wines if "short contact" occurs?
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1 - 4 hours
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What is the length of skin contact in white wines if "long contact" occurs?
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up to 24 hours
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Phenolic extraction is greatest at low or high must temperatures?
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high
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If an age able white wine is being produced what impact does skin contact have?
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contributes to bouquet
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Does ripeness of the fruit have any impact on skin contact in white wine?
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More ripe the fruit, less time required for skin contact
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What are two undesirable stereoisomers that might occur in wines if there is skin contact but unripe grapes?
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"green", "leafy"
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What family of grapes can typically develop bitterness if there is skin contact?
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Muscat
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In what grape is some skin contact almost always used during white wine making?
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Chardonnay
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Maximum color and tannin extraction will typically occur in how many days during the fermentation of red wine?
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9
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What are the four types of skin contact that occur in red wine making?
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1 - no contact
2 - short w/out fermentation 3 - short during fermentation 4 - long during fermentation |
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What is the common name for a fermentation technique that does not require crushing or de-stemming?
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Carbonic maceration
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What is thermo-vinification?
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pre-heating grapes or must to enhance low color intensity
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Which are more easily extracted during fermentation, pigment or tannins?
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pigment
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Name three components that are higher in the press run than the free run.
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pigments, tannins, acidity
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The higher compound levels from the press run are related to what action during the making of the press run?
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pressure level exerted and type of pressure used
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In general, which produces better wine, free run or press run?
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Free run
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Press run is often used in what ways to enrich a final wine?
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Blended with free run, increases color, tannins, complexity
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What polyeric compounds tend to cause colloid coagulation in wine?
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pectins
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What are the two major categories into which wine presses are grouped?
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batch & continuous
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What are three kinds o batch presses that have historically been used in wine production?
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vertical basket, horizontal and bladder press
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What are the primary advantages of a continuous press over batch presses?
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no time in loading & discharging
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What are the primary disadvantages of a continuous press over batch presses?
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breaks skin's tissue
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Define lees.
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solid particles suspended in the must after crushing / pressing
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What is the purpose of a lees filter?
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clears juice from its lees
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Unfermented free run makes up what % of total extractable juice?
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75 - 85%
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Fermented free run is what % of the total wine volume?
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85 - 90%
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What are the two acidity parameters that are used to describe the acidity of must?
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total acidity & ph
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Titratable acidity is better known by what name?
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total acidity (concentration of acids)
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The acidic (sour) taste in wine is most dependent on which acidity paramater?
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Total acidity
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What are the two types of acidity problems commonly found in wine?
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surplus & deficiency
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What are the major techniques used for acid correction when it is deficient?
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blending with high acid must & ion exchanging
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What is the most practical and most frequent method of correcting acidity in wine?
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acid adjustment
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What are the acids most commonly used to correct the problem of there is insufficient acid in the must?
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tartaric, malic, citric
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What is the main reason for acid deficiency in must?
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Reduction of malic acid during ripening period
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What acid should not be used to correct acid deficiencies if a MLF is planned?
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Citric
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High acid concentrations in fruit are usually caused by what common occurrence?
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Harvesting under ripe grapes due to viticultural difficulties, like weather
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What type of climate zone produces grapes that are high in acid?
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cool regions
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What are common techniques to reduce the acidity of must?
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chemicals or blend with low acid/high ph must
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What is the best method to reduce the acidity of must?
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tartaric
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What is considered the normal range of alcohol concentration in wine if all of the sugar is converted to alcohol?
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10 - 13%
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What are the two most common sugars used to increase the cugar content of the must?
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cane sugar / grape concentrate
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When is the best time to add sugar to the must?
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beginning of fermentation
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Sugar addition is also known by what name?
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chaptalization
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Wine yeasts generally belongs to what genus of yeast?
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saccharomyces
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What are the special characteristics of yeast that must be considered when choosing a yeast for wine making?
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tolerance to different conditions, different by-products during fermentation; flocculation capabilities (i.e. the ability to remove sediment)
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What yeast will remain active at high alcohol levels?
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saccharomyces bayamus
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What media conditions control yeast growth?
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sugar concentration, temperature, alcohol concentration, nutrients, oxygen and chemicals present
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What is the minimum starting temperature for white wine must to start fermentation?
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10 - 14 degrees C
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What is the normal starting temperature for red wine must to start fermentation?
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22 - 30 degrees C
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Alcohol has what impact on yeast growth?
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inhibits
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What is the preferred temperature range for white wine making?
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46 -57 degrees F
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What is the preferred temperature range for red wine making?
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72 - 82 degrees F
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Theoretically, how many degrees can a fermentation rise during fermentation?
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30 degrees C
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What are 3 methods to control temperature in wine making?
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cooling liquid jacket around the tank; dripping cold water on outside of tank walls; air conditioned room
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What is the common method of controlling the fermentation temperature when barrel fermentation is employed?
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Air conditioning
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Sugar is not directly converted into alcohol, how many steps are required to convert sugar to alcohol?
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3
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What is the impact of high sugar concentrations (in the 30 - 40B range) during fermentation?
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Starting might be difficult and it could stop too soon.
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Pumping-over or pushing down the cap is used to extract what from the skins in red wine making?
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color & tannin extraction
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What are the most common reasons for a stuck fermentation?
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Lack of oxygen; lack of nutrition; unviable yeast; low temp
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What by-products of fermentation, in addition to alcohol, have a majot impact on a wines flavor and quality?
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glycerol; methanol; higher alcohol; succinic acid; lactic acid;
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What is the minimum temp for MLF to occur?
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17 - 20 degrees C
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What is a major by-product of MLF?
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Acetic acid
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What are the common practices to inhibit MLF?
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early racking, early fining, sulfur-dioxide added
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What is the desirable bacteria genus for starting MLF in wine?
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Leuconostoc-oenus
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What are three styles of still wine that have at least 1% RS and the range of RS in each?
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Off-dry table wines (1 - 2.5%), sweet dessert wines (3% - 28%), late harvest (8 - 12%)
Look up in book |
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What are the five most common grapes used to produce late harvest wines?
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Riesling, Guwurtztraminer, Savignon Blanc, Semillon, Hungarian Tokay
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What are the two ways that late harvest grapes concentrate sugar?
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drying grapes, noble rot
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How does the production of late harvest wine differ from normal still wine?
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higher pressure and more cycles of pressing
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Name three of the most common methods for stopping fermentation or to allow for later re-fermentation?
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Deep cooling, imposing stress on yeast, adding alcohol
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Any unfermented sugar in wine is a cause for chemical instability, what are methods to control or preserve wine from refermentation?
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Yeast inhibitors, pasteurization, sterile filtration
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What is the purpose of racking wine?
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Clarify / aerate wine - separate solids
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Stabilization is a term used to prevent what from occurring in the bottle?
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cloudiness & settling of particles
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What occurs during racking?
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clarify and aerate
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Blending is used in order to achieve what goals (overcoming defects, balancing the wine, enhancing complexity)
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Overcoming certain deficiencies or defects; balancing the wine and enhancing complexity
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Blending is a term used to describe a variety of different processes. What are four different ways a wine can be blended?
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different varieties, different vintages of same variety, different vineyards or locations of same variety, different lots of the same vintage
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What parameters can be corrected by blending?
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acidity, ph, alcohol, color, tannins, varietal aroma, freshness, fruitiness
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What are five different materials used in storage containers?
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wood, concrete, iron, plastic, stainless steel
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What two container materials must be lined before they can be used to store wine?
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concrete, iron
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What are the objectives of fining?
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aid precipitation of suspended materials, reduce color or undesirable smells, stabilize against future cloudiness
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What are five common fining agents used in wine making?
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bentonite, activated carbon, gelatin, egg whites, PVPP
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What are the goals of oak aging wine?
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slow oxidation; adding oak phenols
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What are the extracted compounds from oak?
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non-flavonoid phenols
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What are two acids most commonly extracted from oak?
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vanillic acid and ellagic acid
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For how many years can compounds be extracted from a barrel?
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7 - 10 years
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What are the main French oak regions?
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Limousin, Bourgogne, Allien, Troncais, and Vosges
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What are the names of the main barrel shapes?
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Bordeaux, and Bourgogne
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What are the two styles of a Bordeaux barrel?
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Chateau and Export
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What are the two styles of Burgandy barrels?
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Traditional and Export
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What are three types of toasting?
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Light, medium and heavy
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What is the depth of toasting when it is a light toast?
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surface of interior walls
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What is the depth of toasting when it is a medium toast?
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2mm inside wood's surface
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What is the depth of toasting when it is a heavy toast?
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3 - 4mm inside wood's surface
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What is the importance of humidity in barrel aging below 60% RH?
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water evaporates through barrel more than alcohol
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What is the importance of humidity in barrel aging below 60% RH?
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alcohol evaporates through barrel wall more than water
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