Wine Components & Winemaking Flashcards
What is the predominant alcohol in wine?
Ethanol
What are the main types of acid in grapes?
Tartaric and Malic
What is the typical total acidity in wine?
5.5-8.5g/L
What is pH?
A scale of measurement for the concentration of the effective acidity of a solution
What is the typical pH range of a wine?
3 to 4
How does the pH scale work?
It is an inverse scale so the lower the number, the more concentrated the acidity.
The scale is logarithmic so a pH of 3 is 10 times more acidic than a pH of 4
How does a low pH affect a wine?
A low pH increases the microbiological stability of a wine
Increases the effectiveness of SO2
Gives red wines bright red colour
Enhances wine’s ability to age well
What are the 4 sources of aromatic compounds in wine?
Aromas from the grapes
Aromas created by fermentation from precursors
Aromas originating from fermentation and it’s by-products
Aromas from other sources
What are 2 examples of aromas that come from the grape?
Methoxypyrazines and Rotundone
What are 2 examples of aromas that are created by fermentation from precursors?
Thiols and Terpenes
What are 3 examples of aromas originating from fermentation and it’s by-products?
Esters
Acetaldehyde
Diacetyl
What are Esters?
Compounds which has formed by the reaction of certain acids and alcohols.
Majority are created through the actions of yeasts in the fermentation process.
They are responsible for many fresh and fruity aromas, the most common ester is Oamyl Acetate which gives banana aromas
What is Acetaldehyde?
It is an aroma that occurs in wine due to the oxidation of ethanol.
It masks fresh fruit aromas and has a stale smell regarded as a fault in most wines
It is an important component in the smell of Fino Sherry
What is Diacetyl?
It is an aroma that is produced during fermentation and especially during Malolactic Conversion
It contributes a buttery aroma
What is Eucalyptol?
It is an aroma volatized from Eucalyptus trees by heat and absorbed into the waxy layer of the skins of grapes in nearby vines
What is the allowed residual sugar in a Dry/Sec/Trocken wine?
Up to 4g/L or not exceeding 9g/L provided that total acidity is not more than 2g lower than RS content
What is the allowed residual sugar in a Medium Dry/Demi Sec/Halbtrocken wine?
More than 4g/L and not more than 12g/L or up to 18g/L provided that total acidity is not more than 10g below the RS content
What is the allowed residual sugar in a Medium/Medium Sweet/Moelleux/Lieblich wine?
More than 12g/L and not exceeding 45g/L
What is the allowed residual sugar in a Sweet/Doux/Suss wine?
At least 45g/L
Why is oxygen threatening for the production of fresh fruity wines?
Oxygen breaks down the aroma compounds that gives these wines their style