CSW Prep - Wine Composition and Chemistry Flashcards
What are the major categories of chemicals found in wine?
Water Alcohol Acid Sugar Phenolic Compounds
The acronym WAASP is helpful to remember what?
The major chemicals found in wine. Water, Alcohol, Acid, Sugar, Phenolic Compounds
What is important to know about water?
Makes up 80-90% of wine.
How much of wine is made of water?
80-90%, typically from the grapes themselves.
Why would winemakers add water to wine?
Intentionally dilute if alcohol or phenolic compounds beyond desired levels.
What is the primary compound in wine?
Water
What is the second major compound in wine?
Alcohol
What is the approximate amount of alcohol commonly found in wine?
10-15%
What are the most common kinds of alcohol found in wine?
Ethyl Alcohol (Ethanol) Glycerol Methyl Alcohol (Methanol) Fusil Oils (Higher Alcohols
What is the most common kind of alcohol found in wine?
Ethanol.
What is the result of fermentation (Yeast + Sugar = ?)?
Ethanol (Alcohol)
What is the intoxicating element in wine?
Ethanol.
True or False: Ethanol is a volatile compound?
True. meaning that it evaporates easily.
What is a volatile organic compound?
Organic chemicals that have high vapor pressure at ordinary room temperature.
What is the subjective reference for alcohol level?
“Body.” Light body wines tend to have less alcohol.
What is the key component that differentiates wine from other forms of alcohol?
Acid.
What type of is most reliant on acid for flavor structure?
White Wine.
What are the principle acids in wine?
Tartaric Acid Malic Acird Lactic Acid Acetic Acid Succinic Acid Citric Acid (CLAMS T)
What is tactic acid?
White crystalline diprotic acid. It has the propensity to form tactic crystals (yes cream of tartar) at low temperatures.
What happens when tactic crystals form?
Crystals will not redissolve into the wine and wine will be noticeably less acidic.
What is malic acid?
Dicarboxylic acid, made by all living organisms, contributes to pleasantly sour taste in fruits.
Associated with green apples.
Where is the most common source of malic acid?
Underripe grapes (think green apple).
What types of wines a least like to have high malic acid?
Wine made from grapes grown in hot, warm climates, where grapes ripen easily. Malic acid commonly found in underripe grapes.
What is lactic acid?
Acid not found naturally in grapes but created by lactic bacteria. Lactic bacteria convert malic acid into lactic acid.
What is malolactic fermentation?
Process in winemaking where tart-tasting malic acid, naturally present in grapes, is converted to softer-tasting lactic acid.
Which is less intense: Lactic acid or malic acid?
Lactic acid. But it is not found naturally in grapes, it is created by malolactic fermentation.
Which is found naturally in grapes: Malic Acid or Lactic Acid?
Malic acid.
What is acetic acid?
Acid of vinegar.
What is the most volatile type of acid commonly found in wine?
Acetic acid, readily joins the aromas of wine.
What are the two numbers used to describe the acidity of wine?
(1) Total Acidity (TA), and (2) pH
What is total acidity (TA)?
Volume of all acids found in wine.
What does pH calculate?
Calculates the combined STRENGTH of acids presenting wine. The lower the pH, the stronger the acids.
What is the typical range for acidity strength in wine?
2.9 and 3.8 on pH scale.
What is Succinic acid?
Acid found in wine and common by-product of normal alcohol fermentation.
How is citric acid sometimes found in wine?
Added to increase total acidity, as it is not commonly found in grapes.
How much sugar is typically found in grapes?
15-28 percent sugar at harvest.
What are the two types of sugar commonly found in grapes?
Glucose and Fructose.
What converts sugar to alcohol?
Yeast.
What is the average recognition threshold for sugar?
Around 1%
What are the most important compounds in wine concerning the chemical construction/destruction process?
Carbohydrates, or compounds containing carbon, hydrogen and oxygen.
What are other common terms for phenolic compounds?
Phenolics, polyphenolics, or polyphenols.
What are anthocyanins?
Phenolic compounds. Give wine blue, purple or red color. Change with acidity level, redder in more acidic wines and blue in less acidic ones.
If a wine is more blue, it may be an indicator of what AND due to what compound?
Indicates that wine may be less acidic, due to phenolic compound - Anthocyanins.
Name three commonly phenolics found in wine.
Anthocyanins Flavones Tannins Vanillin Resveratol
What are flavones?
Yellow pigments found in white wine.
What are tannins?
Astringent or bitter compounds found in skin, seeds or stems that form the backbone to wine structure of big red wines. Also prevent oxidation.
What compounds commonly helps prevent oxidation in red wines?
Tannin
What is vanillin?
Phenolic compound. Aromatic compound in oak that imparts vanilla odor.
What is resveratol?
Phenolic compound believed to have beneficial health effects.
What are aldehydes?
Less common phenolic compound, formed when wine is exposed to air.
Commonly used in making sherry or maderia.
What are esters?
Molecules result from joining acid and alcohol. Largest group of odiferous compounds in wine.
What are the most common dissolved gases found in wine?
Oxygen and carbon dioxide.
What is common problem associated with presence of dissolved oxygen?
Oxidation.
What are sulfites.
Less common phenolic compound. Importance preservative.
What phenolic compound is commonly associated with preservation?
Sulfites. Some people sensitive, so wines destined for US with more than 10 parts per million (ppm) of sulfur dioxide required to place warning on label.
