enology Flashcards
There are five different anthocyanins in Vitis vinifera
cyanidin, petunidin, delphinidin, peonidin and malvidin. Their proportion and levels in grape skins (where they are found) is influenced by the variety and the terroir.
What does turbidity in a wine indicate?
Turbidity indicates a measure of haziness caused by microscopic solid particles in suspension within a liquid. Suspended solids affect a wine’s clarity, rendering the liquid translucent rather than fully transparent (clear) by altering its ability to refract light.
What does “opacity” or “opaque” indicate within a wine?
Opacity is a result of highly concentrated, dark color. In scientific terms, an opaque object does not allow any light to pass through it; in tasting the term is used to refer to those deeply colored red wines which are not possible to see through. An opaque wine may not show high turbidity, or haziness, but it is nonetheless not clear.
What are the causes of cork taint?
2,4,6-trichloroanisole (TCA) and 2,4,6-tribromoanisole (TBA) have been identified as principal causes of the musty off-odors associated with “cork taint.” TCA and TBA are haloanisoles, containing chlorine and bromine atoms, respectively, produced by the degradation of halophenols by fungi and bacteria. Halophenols are present in certain manmade chemicals (chlorine bleach, wood preservatives, flame retardants) and they appear in chlorinated drinking water, but they do not occur naturally in wine.
What are monoterpenes and where are they found?
This family of related compounds is responsible for the highly aromatic, floral and sweet citrus notes of Muscat Blanc à Petits Grains, Gewürztraminer, Torrontes, Viognier, and (to a lesser extent) Riesling and Albariño. Terpenes are usually strong-smelling compounds—the word “terpene” is derived from “turpentine”—and white varieties given voice by sufficient monoterpene content are known as “aromatic” varieties. Monoterpenes accumulate during ripening. Botrytis cinerea also tends to reduce monoterpene content; thus, Muscat is not usually a good candidate for noble rot.
cis-rose oxide
cis-rose oxide: The monoterpene responsible for Gewürztraminer’s unique rose and litchi aromatics has a very low threshold for detection, resulting in the grape’s incredible intensity of aroma.
Linalool
Linalool: This slightly spicy, highly floral compound is, alongside geraniol (the scent of geraniums and lemon) and nerol (orange and rose), responsible for the intense fragrance of Muscat wines. Unlike most monoterpenes, linalool amasses in the grape’s flesh, not its skin, and therefore attains a high proportionate concentration in must.
Citronellol
Citronellol: During fermentation, certain yeast strains may form citronellol (dihydrogeraniol) through the reduction of geraniol. Citronellol gives a citronella candle its characteristic floral scent.
Alpha-terpeniol
Alpha-terpeniol: A less aromatic monoterpene—linalool is 10 times as odorous—alpha-terpeniol transmits grapey, pine-like aromas. It is associated with lower-quality Torrontes wines from Argentina.
Rotundone
Rotundone is a sesquiterpene responsible for the highly peppery aroma of Syrah, Grüner Veltliner, Mourvèdre, and the Italian red varieties Schioppettino and Vespolina. It has a very low detection threshold—just a few parts per billion—but a sizable segment of the population is totally unable to smell the compound. Rotundone accumulates in the grape skin, and increases in concentration during the period from véraison to harvest.
Typical Examples of High Aromatic Intensity Varietals/Styles
Gewürztraminer, Muscat Blanc à Petit Grains, Viognier, Torrontes, Marlborough Sauvignon Blanc, Beaujolais Nouveau, Sauternes
Typical Examples of Elevated Aromatic Intensity Varietals/styles
Albariño, Barolo, Carmenère, Mendoza Malbec, Zinfandel, Napa Valley Sauvignon Blanc, Young Vintage Port, Amarone della Valpolicella, Beaujolais Cru, Red Burgundy, Alsatian Pinot Gris, Grüner Veltliner, Sancerre
Typical Examples of Medium Aromatic Intensity
Bordeaux Reds, Rioja, Chianti, Cornas, Italian Pinot Grigio, Chenin Blanc
Typical Examples of Diminished Aromatic Intensity
Muscadet, Chablis, Young Hunter Semillon
White fruit tasting categories
Citrus, Pomaceous (Orchard), Stone/Pit, Tropical, Melon
