Wine Components, Faults, Varietals Flashcards
Define Wine.
Wine is the fermented product of grapes.
What creates the character and complexity of wine and where do they come from?
Chemical compounds.
a) the grapes themselves
b) fermentation and wine-making
c) chemical reactions before or during fermentation, or as a result of aging.
What are the 5 major components of wine?
- Water
- Alcohol
- Acid
- Sugar
- Phenolic Compounds
What percentage of wine is typically comprised of water?
80-90%
Where does the water found in wine mostly come from?
Grapes
How much of wine is TYPICALLY comprised of alcohol?
10-15%
What is the primary alcohol found in wine?
Ethyl Alcohol or Ethanol
What secondary alcohols are sometimes found in wine?
a) Methyl Alcohol or Methanol
b) Glycerol
c) Fusel Alcohols/Oil or Higher Alcohols
What is a volatile compound?
One that evaporates easily.
What component of wine most often contributes “weight” or “body”?
Alcohol
What are “legs” or “tears” and what usually causes them?
Slow or fast-moving drops that appear on the inside of a glass after a wine is swirled; slower-moving tears can be caused by higher alcohol.
What percentage of wine is generally comprised of acids?
.5-.75%
What are 2 major and 2 minor acids found in GRAPES?
1) Tartaric
2) Malic
3) (Citric)
4) (Succinic)
What are 3 acids produced during fermentation?
1) Lactic
2) Acetic
3) Succinic
What is the strongest acid, in terms of PH, found in wine?
Tartaric
What acid has a tendency to form solid crystals and how can it be prevented?
a) Tartaric
b) Cold Stabilization
Grapes from what climate are generally high in malic acid?
Cool
Describe the flavor profile of malic acid?
Tart green apples
What winemaking process softens the taste of malic acid?
Malolactic Fermentation or Conversion
Describe Citric Acid?
Present in very small amounts in grapes, sometimes used to increase total acidity during wine making, has a notable citrusy flavor not suitable for quality wines.
What is the catalyst for malolactic conversion?
Lactic Acid Bacteria
What are the characteristics of lactic acid in wine?
Soft, smooth, creamy or buttery mouthfeel
What causes high levels of acetic acid?
Usually a chemical reaction between ethanol and oxygen caused by acetobacter.
Describe the taste of acetic acid.
Vinegar
What characteristic distinguishes acetic acids from other acids?
It’s volatile.
Which acid is both a product of winemaking and found in grapes themselves?
Succinic Acid
Describe the taste of succinic acid.
Sharp, bitter, salty
What are the two measures of acid in wine and what do they measure.
Total Acidity, which measures volume and pH, which measures strength
What is the pH of most wines?
Between 2.9 - 3.9
What kind of scale is pH measured on what does that mean?
Logarithmic, so the lower the number, the stronger the acid
What measure determines sulfur additions during winemaking?
pH
Grapes contain what percentage of sugar AT HARVEST?
15-28%
What two sugars are found in roughly equal amounts in grapes?
Glucose and Fructose
What is a monosaccharide?
A “simple” sugar which can be converted into alcohol by yeast without being broken down first.
What does “dry” mean with respect to a wine?
A wine with less residual sugar than a person can detect
What is RS
Residual sugar, or sugar remaining after fermentation, measured as a percentage or g/l.
What are three terms for phenolic compounds?
phenolics, polyphenols or polyphenolics
Name five phenolic compounds found in wine.
1) Anthocyanins
2) Flavonols
3) Tannins
4) Vanillin
5) Resveratrol
What characteristic do anthocyanins contribute to wine?
Color in red wine, ranging from blue to purple to red
Red wines with higher acidity appear more _____________.
Red
What color pigment do flavonols contribute to white wine and what causes them to increase?
a) Yellow
b) Sunshine
Name 4 places in which tannins can be found?
1) Seeds
2) Skins
3) Stems
4) Oak
Tannins are a natural _________________ that protect wine from _________________ during the aging process.
a) preservative
b) oxidation
What is the aromatic quality of Vanillin and where does it come from?
a) Vanilla
b) oak barrels
Vanillin _______________ with light levels of toast and __________________ with heavier levels of toast.
a) increases
b) decreases
What is resveratrol and where is it primarily found?
a) a compound with beneficial health effects
b) skins and seeds of grapes
What is polymerization and how does it pertain to wine?
Chains of molecules phenolic compounds such as tannins tend to form in bottle. Over time, the chains become too heavy and drop out of suspension, which changes the characters and sometimes increase the complexity of the wine with age
What are 4 additional components of wine?
1) Esters
2) Aldehydes
3) Dissolved gases
4) Sulfites
What is an aldehyde and what is the most common example of one?
a) the combination of an alcohol and oxygen
b) Acetaldehyde, common in Sherry
What are esters and what is a common example of one?
a) The combination of an acid and an alcohol
b) ethyl acetate, the combination of ethanol and acetic acid
What are two dissolved gases found in wine and where do they come from?
a) O2, the atmosphere, can cause oxidation
b) C02, fermentation, contributes petillance or carbonation
Why do all wines contain SOME trace of sulfites?
It’s a natural by-product of fermentation.
Wine containing greater than __________________ of sulfur dioxide must state “Contains Sulfites” on the label.
10 ppm
What causes “cork taint”?
Mold that interacts with other compounds and generates the compound 2,4,6-trichoroanisole, or TCA
How many bottles are thought to be affected by TCA and at what levels can it be detected?
a) 1-8%
b) 2-7 ppt
What effect does TCA have on wine?
Taste and aroma of moldy cardboard or wet dog
What are three sulfur-based causes of off-odors in wine?
1) SO2 - Sulfur Dioxide
2) H2S - Hydrogen Sulfide
3) Mercaptan
What effect does excess SO2 have on wine?
Odor of burnt match, burning sensation in the throat
How does pH relate to the perception of SO2?
The more acidic the wine, the greater the perception of SO2
What is the effect of excess H2S on wine?
Odor of rotten eggs
What causes excess of H2S in wine?
Absence of oxygen, sometimes prolonged contact with yeast sediment in barrel or tank
What is Mercaptan and how does it affect wine?
a) combination of sulfur and ethanol.
b) odor of garlic or onions
What are 5 off-odors in wine relating to bacteria?
1) acetic acid - vinegar
2) butyric acid - rancid butter
3) lactic acid - sauerkraut or goat
4) ethyl acetate - nail polish remover or glue
5) geranium fault - crushed geraniums
What is VA?
Volatile acidity, the pronounced aroma of white vinegar caused by acetic acid.
What is ascensence?
High VA combined with high ethyl acetate.
What is ethyl acetate?
An ester formed through the reaction of ethanol and acetic acid
What causes geranium fault?
The metabolism of sorbic acid (from the preservative potassium sorbate) during malolactic fermentation
What is Brett and what effect does it have on wine?
a) Short for Brettanomyces, a yeast found in and around wineries
b) sweaty, horsy, band-aid, medicinal odors
Why would a wine be described as “green”?
Odor of leaves, caused by young, underripe grapes
What is the effect of “oxidation” on wine?
Muted fruit character, browning; not always a flaw, can contribute a nutty, caramelized character
What does it mean if a wine is described as “maderized”?
Cooked or baked quality, caused by excess exposure to heat or oxygen
What causes a wine to smell “moldy” or “rubbery”?
a) presence of mold on grapes or barrels
b) low-acid, excess sulfur
What does “stagnant” mean with respect to wine?
Stale water odor
What does “stemmy” mean with respect to wine?
Bitter, green odor of grape stems
What causes the odor of “wet cardboard” in wine?
TCA or misuse of filter pads
Describe what is meant by “leesey” or “yeasty”?
Wine that’s rested on dead yeast too long; not considered a flaw in many sparkling wines