Chapter One - Wine Composition and Chemistry Flashcards
The component that makes up 80-90% of the volume of most wines
Water
Slow moving “tears” that may appear in a wine glass after the wine is swirled
Legs
Has little or no sensory impact on the majority of quality wines
Citric Acid
The component that makes up 10-15% of the volume of most wines
Ethyl alcohol
A type of secondary alcohol
Glycerol
A sharp tasting acid often associated with green apples
Malic acid
An acid produced via the conversion of malic acid
Lactic acid
An acid with a slightly bitter, slightly salty flavor
Succinic acid
Of the six main acids found in wine, list those that are typically found in unfermented grapes
Tartaric, malic, citric, and succinic acid
Of the acids typically found in grapes, which are found in very small quantities?
Citric Acid
Succinic Acid
Which acid is known to cause deposits known as wine diamonds?
Tartaric acid
What is the name of the winemaking process that, in addition to changing a wine’s acid components, often provides wines with a creamy texture and a buttery aroma?
Malolactic Fermentation
What measurement is used to define the volume of all the acids present in a wine?
Total Acidity (TA)
What does pH measure?
The combined chemical strength of the acids present
What is a typical pH measurement of a highly acidic wine?
2.9
What pH measurement would you expect to find in a low acid wine?
3.9
What are the two main fermentable sugars found in wine grapes?
Glucose
Fructose
What term is used to describe a wine that does not contain any detectable sugar?
Dry
Yellow pigments found in white wine
Flavonols
An aromatic compound found in oak barrels
Vanillin
A compound found in wine believed to be beneficial to human health
Resveratrol
One of the most common esters found in wine
Ethyl acetate
The specific component that gives fino Sherries their distinctive aromas
Aldehyde
The compounds that give red wine its red, blue, or purple hue
Anthocyanins
Bitter compounds found in the skins, seeds, and stems of grapes
Tannins
Molecules that result from the joining of an acid and an alcohol
Esters
Matter sometimes formed as a result of polymerization
Sediment
A preservative widely used in winemaking
Sulfur
The Oxidized alcohol formed when wine is exposed to air
Acetaldehyde
Promotes the release of the wine’s aromatic compounds
Carbon Dioxide
T/F
Red wines that are highly acidic tend to appear more blue in color, whereas low-acid red wines appear more red
False
T/F
Tannins can create a textural, drying sensation on the palate
True
T/F
Madeira is an example of a wine that is produced in such a way that oxidation is encouraged and expected
True
T/F
Flavanols increase in white grapes with increased exposure to sunlight
True
T/F
The aromatic compound vanillin, found in vanilla beans, is not found anywhere else in nature
False
T/F
The phenolic compounds of a grape are concentrated primarily in its skin and seeds
True
T/F
Wines may become oxidized after being exposed to heat
True
T/F
It is common for winemakers to encourage the oxidation of white wines such as Chenin Blanc and Riesling by maximizing air exposure during the preliminary stage of fermentation and aging
False
T/F
Ethyl acetate imparts an aroma similar to nail polish remover or glue at very low concentrations, whereas at higher concentrations it tends to smell of dried rose petals or perfume
False
T/F
Esters represent the largest group of odiferous compounds found in wine
True
T/F
Wines with greater than 2 ppm of sulfur dioxide are required to display the “contains sulfites” warning on the label
False
T/F
Normal fermentation does not produce enough carbon dioxide to make a difference in the flavor profile of a typical table wine
False
What is the most prevalent type of acid found in both vinifera grapes and wine?
Tartaric acid
Which phenolic compounds is responsible for the bitter taste and drying textural sensation found in many red wines?
Tannin
What is a type of molecule that results from the joining of an acid and an alcohol?
Esters
What is the typical pH range found in table wines?
2.9 to 3.9
What is a wine diamond?
A small particle created via the crystallization of tartaric acid
What is methyl alcohol?
A secondary alcohol produced via fermentation
In the United States, wine with more than 10 ppm of this compound must have a warning label
Sulfites
Which compound gives red wines their red, blue, or purple hues?
Anthocyanins
Which acid, created in small amounts during typical fermentation, is found in many types of vinegar?
Acetic acid
Which compound could cause a wine to have slow, thick tears?
Alcohol
What wine is most likely to be high in aldehydes?
Sherry
What is an ester?
An ester is a molecule that results from the joining of an acid and an alcohol. They form a large group of highly ordiferous compounds often found in wine.
Grapes typically contain 15% - 28% of _____ at harvest?
Sugar
Which of the following wines will be more acidic?
- wines with a pH of 2.9
- wines with a pH of 3.6
2.9
What are the two main types of acid found in wines?
Malic acid and tartaric acid
The main type of potable alcohol found in wine
Ethanol or ethyl alcohol
This type of molecule often results when wine is exposed to air
Aldehyde
Five major components of wine
Water Alcohol Acid Sugar Phenolic
The main type of potable alcohol in wine
Ethanol (Ethyl Alcohol)
The most prevalent acid found in both grapes and wine
Tartaric acid
Another term for tartrates
Wine diamonds (tartaric acid)
Conditions that lead to a drop in malic acid
Warm/hot climate
The ripening phase
Over-ripe grapes
Malolactic fermentation
Acid that is both a minor component of grapes, and a by product of normal alcoholic fermentation
Succinic acid
Typical range of pH for most wines
2.9 to 3.9
Sugar remaining in a wine post fermentation
Residual sugar
Yellow pigments found in white wines
Flavonols
What is meant by “polymerization”
When molecules (such as tannins) combine into longer molecule chains
Chemical reactions resulting from dissolved oxygen
Oxidation
In the US, wines containing more than ____ ppm of sulfur dioxide must carry a warning label
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