Chapter One: Wine Composition and Chemistry Flashcards
Five major components of wine
Water Alcohol Sugar Acid Phenolic compounds
Acetic Acic
A highly volatile acid, often found in vinegar
Ethanol (Ethyl alcohol)
The main type of potable alcohol in wine
Malic acid
Acid reminiscent of green apples
Tartaric acid
The acid most prevalent in both ripe grapes and wine
Wine diamonds
Tartaric acid crystals, another term for tartrates
What do these lead to a drop in for grapes?
- warm/hot conditions
- the ripening phase (respiration)
- over-ripe grapes
Malic acid
Lactic acid
Acid not found in grapes, but often produced during secondary (malolactic) fermentation
Succinic acid
Acid that is both a minor component of grapes, and a by-product of normal alcohol fermentation
What is the typical range of pH for most wines?
2.9-3.9
What are the two main fermentable sugars found in grapes?
Glucose
Fructose
What is the sugar remaining in a wine post-fermentation?
Residual sugar
What are the compounds that give red wine its color?
Anthocyanins
What are the yellow pigments found in white wines?
Flavonols (flavones)
What are the sources of tannin?
Grapes: seeds, skins, stems
Wood: oak barrels and other wood products
What is the compound found in red wine known for health benefits?
Resveratrol
What is polymerization?
The process by which molecules (such as tannins) transform/combine into longer molecule chains
What are aldehydes?
Oxidized alcohols
What are esters?
Molecules that result from the joining of an acid and an alcohol
What is oxidation?
Chemical reactions resulting from dissolved oxygen
In the US, wines containing more than ___ ppm of sulfur dioxide must carry a warning label
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