General Flashcards
Wine is typically what % water?
80-90
Major components of wine
5
- Water
- Alcohol
- Acid
- Sugar
- Phenolic compounds
Wine is typically what % alcohol?
10-15
What is the primary result of alcoholic fermentation and the main alcohol component of wine?
Ethyl alcohol
Also referred to as ethanol
Name the other types of alcohol that occur in small amounts in wine
(3)
-Glycerol
-Methyl alcohol (methanol)
-Fuse alcohols or “higher alcohols”
AKA fuse oils
Acid’s usually make up what % of a wines volume?
0.5 - 0.75
The principal acids in wine
6
- Tartaric
- Malic
- Citric
- Lactic
- Acetic
- Succinic
What is the most prevalent of the acids found in both grapes and wine?
Tartaric
What is the strongest acid in terms of pH?
Tartaric
Tartaric acid forms solid crystals at low temperatures called
Tartrates or “wine diamonds”
Once “wine diamonds” form what happens to the wine?
The wine will become noticeably less acidic
What can be done in the winemaking process to avoid or minimize “wine diamonds”?
Cold stabilization
Malic acid is a sharp-tasting acid frequently associated with
Green apples
Which grapes are typically high in malic acid?
Under-ripe grapes
and
Cool-climate grapes
Wines from what type of grapes or grown in what climate tend to have low levels of malic acid?
Overripe grapes
Or
Grapes grown in hot climates
High levels of malic acid can be assuaged using what winemaking technique?
Malolactic fermentation
What acids are used to increase the total acidity in a wine?
Citric
What flavor does citric acid have?
Citrus-fruit flavor
What bacteria is optionally added to wine to alter its acidity?
Lactic acid bacteria
Is lactic acid found in grapes?
No
Which is less intensely acidic?
Lactic acid
Or
Malic acid
Lactic acid
Wines that undergo malolactic fermentation tend to be … ?
Softer and smoother in acidity than this that do not
The by-products of malolactic fermentation provide wine in what texture and in some cases what aroma?
Creamy texture
A “buttery” aroma
Which acid is found in most types of vinegar?
Acetic acid
Higher concentrations of acetic acid is typically the result of a chemical reaction between?
Ethanol and oxygen by harmful (to wine) bacteria called acetobacter
Succinic acid flavor profile
Sharp, slightly bitter, slightly salty flavor
Grape acids
3
- Tartaric
- Malic
- (Citric)
Fermentation acids
3
- Lactic
- Acetic
- Succinic
The volume of all the acids in a wine is called?
Total acidity (TA)
What does the pH level of a wine represent?
The combined chemical strength of the acids present
Wine usually measures between what on the logarithmic pH scale?
2.9 - 3.9
Grapes typically contain what % sugar at harvest?
15 - 28
Grapes at harvest contain roughly equal amounts of two sugars
Glucose
And
Fructose
Glucose and fructose are both highly fermentable monosaccharides commonly known as
Simple sugars
Wines that have less sugar than a person can taste are described as
Dry
Depending on the amount of residual sugar, wines may be called
(3)
- Off-dry or medium dry
- Medium sweet
- Sweet
The terms for a large category of various molecules that are present in many wines
(4)
- Phenolic compounds
- Phenolics
- Polyphenolics
- Polyphenols
Phenolics include
6
- Anthocyannins
- Flavones and Flavonols
- Tannins
- Vanillin
- Resveratol
What compounds give red wine it’s color?
Anthocyannins
What influences the color of red wine?
2
The amount of anthocyannins
And
The acidity level of the wine
More acidic wine appears what hue?
Redder
Less acidic wine appears what hue?
Bluer
What are the yellow pigments found in white wine?
2
Flavones
And
Flavonols
What causes flavonols to increase?
Increased exposure to sunlight
What are tannins and where are they found?
Astringent or bitter compounds found in skins, seeds and stems of grapes
Also oak and oak barrels
What is the “backbone” of big red wines?
Tannins
What protects wine from oxidation during the aging process?
Tannins are a natural preservative
What is the aromatic phenolic compound in oak that imparts a vanilla scent to barrel aged wines?
Vanillin
What compound in wine is believed to have several beneficial health benefits?
Resveratol
Where are the phenolics of a grape primarily located?
2
Skin
And
Seeds
What happens when tannins and pigments polymerize (combine into longer molecule chains)?
They become too heavy and drop out of the solution as sediment
What are the oxidized alcohols that are formed when wine is exposed to air?
Aldehydes
What is the most common aldehyde in wine?
Acetaldehyde
How is acetaldehyde formed?
By the oxidation of ethanol
What gives fino sherries their distinct aroma?
Acetaldehyde
What molecules result from the joining of an acid and an alcohol?
Esters
What are the largest group of odiferous compounds found in wine?
Esters
One of the most common esters in wine, the ester of acetic acid and ethanol is?
Ethyl acetate
Ethyl acetate at low concentrations has aromas of
Fruity, flowery aromas
Ethyl acetate at high concentrations has aromas of
Faulty aromas of nail polish remover, varnish or glue
Why is sulfur added during the winemaking process
To absorb any free oxygen molecules before they have the opportunity to harm the wine
What gives sparkling wine it’s bubbles?
Carbon dioxide (CO2)
A natural by-product of fermentation
Many of the important compounds in wine are carbohydrates
Molecules containing
3
- Carbon (C)
- Hydrogen (H)
- Oxygen (O)
Grapevines create carbohydrates from the molecules contained within
(2)
Carbon dioxide
And
Water
During fermentation, yeast cells consume glucose and fructose and convert them into simpler compounds
(5)
- Succinic acid
- Lactic acid
- Glycerol
- Ethanol
- Carbon dioxide
What is TCA?
2,4,6 - Trichloroanisole
Overly high concentrations of sulfur dioxide (SO2) possess what odors?
An acrid smell, similar to burnt matches
When sulfur-rich wines sit too long in the complete absence of oxygen, it develops what odor?
Rotten eggs
When does hydrogen-sulfide (H2S) most often occur?
When a barrel or tank of wine rests for a long time with a large amount of yeast sediment in the bottom
Ethyl mercaptan may form as a combination of
2
Sulfur
And
Ethanol
What does ethyl mercaptan smell like?
Garlic
Or
Onions
Acetobacter can convert alcohol into?
Acetic acid
Acetic acids odor
Vinegar
Butyric acids odor
Rancid butter or spoiled cheese
Lactic acids odor
Like sauerkraut
Or
Goat
Ethyl acetate odor
Fingernail polish remover
When acetic acid and ethyl acetate combine the result is referred to as?
Ascensence
Geranium normally caused by
Incomplete malolactic fermentation
Brettanomyces odor
Sweaty
Or
Horsey
Band-aid like
Or
Medicinal
Brett is a member of what family?
Yeast
Greens odor
Leaves, usually from the use of immature or under ripe grapes
Maderized odor
Cooked
Or
Baked
Maderized results from?
Excessive heating
Or
Oxidation
Rubbery associated with
Very low-acid wines
Or
Excess sulfur
Stagnant odor
Stale water
Stemmy odor
Bitter, green odor of grape stems
Wet cardboard odor
Papery chemical odor frequently associated with cork taint
Many commercial Rieslings are made in what range?
Off-dry to medium-sweet range
Many commercial Rieslings have what level of alcohol?
Low levels of alcohol, some ABV’s as low as 7-8%
This grapes naturally low acidity is blended with Sauvignon Blanc in Bordeaux
Semillon
In Australia, Semillon is often blended with
Chardonnay
Grape used to make balsamic vinegar
Trebbiano
Grape used to make French Cognac
Ugni Blanc
Trebbiano in France
Ugni Blanc
There is more __________ planted than any other quality wine grape in the world
Cabernet Sauvignon
3 requirements to fully ripen Cabernet Sauvignon
- areas with late starting winter
- sufficient heat
- sufficient sun exposure
In Australia Cabernet Sauvignon is often blended with
Shiraz
Grenache thrives in hot, dry conditions where it develops
Considerable sugar and therefore high alcohol
Right bank main grapes
2
Cabernet Sauvignon
And
Merlot
Most widely planted red grape in Germany
Pinot Noir
Pinot Noir aromas when young
4
Raspberry
Strawberry
Cherry
Red Flowers
Pinot Noirs character as it matures
3
Forest Floor
Leather
Mushroom
Barolo and Barbaresco are made from what grape
Nebbiolo
In Rioja, Tempranillo is generally blended with
Mazuelo
