Wine Composition and Chemistry Flashcards
The most prevalent of the acids found in grapes and wine
Tartaric Acid
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 major of quality wine
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 conversation of malic acid
Lactic Acid
An acid with a slightly bitter, slightly salty flavor
Succinic Acid
The acid found in most types of vinegar
Acetic 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 and 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 add-on 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
What does pH measure?
Combined chemical strength of the acids present
What is a typical pH measurement of a highly acidic wine?
2.9 (Lower the # the more acidic)
What pH measurement would you expect to find in a low acid wine?
3.9 (Higher the # the less acidic)
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
Resveratol
One of the most common esters found in wine
Ethyl acetate
The specific component that gives fino Sherries their distinctive aroma
Acetaldehyde
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
Oxidized alcohols formed when wine is exposed to air
Aldehydes
Promotes the release of the wine’s aromatic compounds
Carbon dioxide
(True or False) Red wines that are highly acidic tend to appear more blue in color, whereas low-acid red wines appear more red.
False -
(True or False) Tannins can create a textural, drying sensation on the palate.
True
(True or False) Madeira is an example of a wine that is produced in such a way that oxidation is encouraged and expected
True
(True or False) Flavonols increase in white grapes with increased exposure to sunlight
Ture
(True or False) Raw (untoasted) oak barrels will typically contain higher levels of vanillin than lightly toasted barrels
False - light to medium toasted barrels will bring out more vanillin compounds. However, high toasting will result in less vanillin compounds
(True or False) The phenolic compounds of a grape are concentrated primarily in its skin and seeds
True
(True or False) Wines may become oxidized after being exposed to heat
True
(True or False) 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 stages of fermentation and aging
False -
(True or False) 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
(True or False) Esters represent the largest group of odiferous compounds found in wine
True
(True or False) In the United States, any wine containing more than 2 ppm of sulfur dioxide is required to display the “contains sulfites” warning on the label
False - wines containing more than 10 ppm must have a warning label
(True or False) 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
What phenolic compound 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 - 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 what compound must have a warning label?
Sulfites
What compound gives red wines their red, blue or purple hues?
Anthocyanins
What acid is created in small amounts during typical fermentation, is found in many types of vinegar?
Acetic acid
Two main fermentable sugars present in wine grapes are:
Glucose and Fructose; also known as monosaccharides
The 5 major components of wine
Water, alcohol, acid, sugar and phenolics
The 3 possible/rare components of wine
Bacteria, yeast and protein
Secondary alcohols include:
Glycerol, methanol and fusel alcohols
Slower, thicker tears indicate:
Higher alcohol
Two ways to measure acidity
TA and pH
Terms used to describe acidity
Soft, smooth, fresh, crisp, lively and tart
Often used in acidification and is the strongest in pH
Tartaric Acid
Sometimes used to increase the TA (total acidity)
Citric Acid
Created in wine via a bacteria, as a by-product of MLF
Lactic Acid
Which acid is volatile (evaporates easily)
Acetic acid
Easily reacts to form esters
Succinic acid
Typical sweetness range
~.8% - 24%
Five phenolics
Anthocyanins Flavonols Tannin Vanillin Reservatrol
Four additional components of wine
Aldeydes
Esters
Dissolved gasses
Sulfites
