Winemaking

Question 1

Alcoholic Fermentation

Answer 1

Conversion of sugar into alcohol and CO2, through the action of yeast. Alcoholic fermentation will not start unless at least above 5 degrees C and should continue naturally until all the sugar is consumed.

Question 2

Malolactic Fermentation (MLF)

Answer 2

Usually takes place once alcoholic fermentation is finished and is scarred out by lactic acid bacteria. They convert the tart malic grape acid into the softer lactic acids (found in milk). MLF softens and reduces acidity, as well as creating buttery flavors and producing CO2. MLF can be encouraged by raising the temperature of the wine and by not adding SO2 after the alcoholic fermentation. It can be avoided through storage at cool temperatures, the use of SO2, or by filtering out bacteria.

Question 3

Lees

Answer 3

Directly after fermentation, wine can appear cloudy due to the presence of dead yeast cells and grape fragments. These particles are usually heavy enough to fall to bottom of the vessel, the sediment forms what is know as the gross lees and, if not removed, can cause unpleasant aromas to develop. Smaller particles (fine lees) can settle more slowly, these are often removed gradually through the winemaking process. In some cases the winemaker may choose to keep a white wine in contact with the fine lees during pre-bottling maturation to add flavor and richer textures.

Question 4

Constituents of wine

Answer 4

Ethanol: (8-22%) Main alc. in wine; Sugars (.1-20%) amount of sugar will vary depending on the style of the wine. Acids (.3-1%) Most important acids in wine are tartaric, magic, and lactic. Aroma and flavor compounds( up to .2%): hundreds of different compounds found in very small amounts; Water (70-90%) most abundant component in wine; Tannins and Color (up to .4%) Especially important in red wines.