Chapter One - Composition and Chemistry Flashcards
What are the major components of wine?
- Water
- Alcohol
- Acid
- Sugar
- Phenolic compounds
Discuss Water as a component of wine?
Wine is typically constituted of 80-90% water
Discuss Alcohol as a component of Wine?
Alcohol makes up between 10-15% of wine approx.
Ethyl Alcohol or Ethanol is the primary result of alcoholic fermentation.
You can also find other types of Alcohol including glycerol, methyl Alcohol(methanol) as well as Fusel alcohols or higher alcohols
It is an intoxicating element and a volatile compound, meaning that it evaporates and carries the aromas to the nose.
Alcohol content contributes to the mouth filling sensation which also is referred to as the weight or body
Discuss Acid in terms of a component of Wine?
Acid comes in a variety of types in wine. It attributes the structure, balance, and thirst quenching refreshment.
Usually known to make up between .5% and .75%
The types of Acid include:
Tartaric Acid
Malic Acid
Citric Acid
Lactic Acid
Acetic Acid
Succinic Acid
What is Tartaric Acid?
The most prevelent of the acids found in wine.
It is also the strongest in terms of PH.
This acid also has the ability to form crystals at low temperatures. This can not redissolve into the wine and you find that the wine will become less acidic when this happens.
You can lessen the chance of this happening by the process of cold stablization.
What is Malic Acid?
Sharp tasting acidity that is mostly associated with green apples.
Caused by underripe grapes and cool climates.
Malolactic Fermentation can change this strong acid into lactic acid which has a softer and creamier texture on the palate.
What is Citric Acid?
Not normally considered to be part of grapes as it is in such limited quantities. It does not impart any sensory impact.
However… it is sometimes added to wine to increase the total acidity. The citrus flavors though are not suitable for high end wines.
What is Lactic Acid?
Lactic Acid is not found or present in wine but it must be created by the process of Malolactic fermentation.
Turning strong malic acids in to a softer lactic acid which adds a creamy texture or a “buttery” aroma.
what is Acetic Acid?
The acid that is found in most types of Vinegar.
This type of acid is created during fermentation. It is also known to be volatile, which means that it evaporates and joins in on the aroma party to your nose!!
This is a component that will add to the bouquet.
However in large quantities it can be harmful to wine. it becomes what is known acetobacter. This makes the wine undrinkable and unpleasant.
Acetobacter is a bacteria
What is Succinic Acid?
A minor component of grapes and a by product of alcoholic fermentation.
A sharp slightly bitter, and slightly salty flavor.
Which acids that are found in wine are from the fermentation process?
Lactic Acid
Acetic Acid
Succinic Acid
Which acids are natural acids found in grapes?
Tartaric Acid
Malic Acid
Citric Acid - in small amounts
Succinic Acid - in very small amounts
How are the levels of Acidity measured in wine?
There are two numbers that describe the acidity levels in wine.
The first is TA or Total Acidity.
This is the volume of all Acids in wine.
** Not all acids are created equal. Some are stronger than others so to accurately measure this we also look at the PH.
PH is the second number that we use to look at the acidity in wine. The PH looks at the combined chemical strength of the acids.
The scale is usually read on a logarithmic PH scale between 2.9 and 3.9.
The lower number illustrates a stronger acidity.
although PH is looked at more closely.
Discuss Sugar as a component of wine.
Grapes typically contain about 15% - 28% sugar at harvest.
roughly equal amounts of 2 types of sugars
- Glucose
- Fructose
Both are monosaccharides or “simple sugars”
What are Phenolic Compounds?
A large category of various molecules that are present in many wines. Which occur in Minute quantities - although they can have major impact on the sensory profile of a wine.
What are the most common Phenolic compounds?
- Anthocyanins
- Flavonols
- Tannins
- Vanillin
- Resveratrol
What are Anthocyanins?
compounds that give red wine their color. They range in color from blue to purple to red.
The color of red a red wine is influenced by both the amount of anthocyanins and the acidity level in the wine. More acidic wines appear redder in hue, while less acidic wines appear bluer.
What are flavonols?
These yellow pigments are found in white wines. This will increase in grapes with increased exposure to sunlight; Therefore, white wines from sunnier climates tend to have more golden color than white wines from cooler (or cloudier climates.
What are tannins?
Tannins are astringent, bitter compounds found in the skins, stems, and seeds of grapes.
They are also found in oak and oak barrels.
They form the backbone and a major part of the structure of big red wines.
They are also a natural preservative and help to protect red wines from oxidation during the aging process.
When Young - tannins are easily recognizable by the textural, drying sensation they create in the mouth!
What is Vanillin?
Vanillin is an aromatic phenolic compound in Oak that imparts a vanilla scent to barrel-aged wine.
Mostly associated with American oak.
Although it varies according to several factors
- The amount of seasoning used in the oak preparation.
The size of the barrel
The age of the barrel
The species of oak
The lighter the toast the higher amount of vanillin one can find.
What is Resveratrol?
A compound in Wine believed to have several beneficial health effects on humans.
ADDDDDDD
Discuss Phenolic compounds in terms of fermentation? Red vs White.
Over time some phenolic compounds, particularly pigments and tannins tend to polymerize. These chains may eventually get to heavy or long to stay suspended in liquid and drop out of the solution as sediment.
This development has a major impact of the flavor of wine and is one of the main results of the aging process.
over time this will make a red wine lighter in color and less astringent
Whites will deepen in color.
Name some other components that can be found in wine?
Aldehydes
Esters
Dissolved Gasses
Sulfites
What are Aldehydes?
Aldehydes are oxidized alcohol that are formed when the wine is exposed to air.
Some wines are made intentionally to encourage this - Sherry, Madeira
though all wines with take on aldehydic or Maderized characteristics when exposed to excessive amounts of oxygen during fermentation or aging.
They can also get these characteristics when they are open to long or exposed to heat.
The most common aldehyde is acetaldehyde.
This is formed by the oxidation of ethanol. This contributes to the distinctive aroma of fino sherry.
