Acetic acid | The main acid in vinegar. |
Acetification | The formation of acetic acid (vinegar). |
Aroma | Wine odors derived from grapes. |
° Balling | A measurement of sugar in fermenting wine. |
Bentonite | A type of clay used for heat stability. |
Bound SO2 | Sulfur dioxide that combines with other compounds. |
Bouquet | Wine odors derived from processing, such as fermentation and oak aging. |
° Brix | Measurement of sugar in juice. |
Cap | The skins and pulp of crushed grapes that separate from the juice and float to the top during fermentation. |
Carbon dioxide![]() CO2 |
A gas formed during fermentation. |
Carboy | A glass container |
Cold stabilization | The removal of tartrates in wine to prevent precipitation in bottled wine. |
Crusher | A device that breaks grapes skins to allow for juice extraction. Often re- moves grapes from their stems as well. |
Deacidify | To reduce the total acidity in wine or juice. |
Dry | A wine with no fermentable sugar. |
Ethyl acetate | A compound smelling like nail polish remover. |
Ethyl mercapton | A compound smelling like cooked asparagus. |
Fermentation | The conversion of grape sugar by yeast to alcohol and carbon dioxide. |
Fermenter | A container for fermenting wine. |
Fermentation lock | A device that allows CO2 to escape and prevents air from entering a container of wine. |
Finish | The taste of wine that remains in the mouth after swallowing. |
Free run | Juice or wine that flows from grapes without pressing. |
Free SO2 | Sulfur dioxide actively available to protect wine. |
Heat stabilization | The removal of excess proteins to prevent cloudiness in bottled wine. |
Hydrogen sulfide | A compound smelling like rotten eggs. |
Hydrometer | A device used for measuring sugar in juice or must. |
Lactic acid | An organic acid produced from malic acid by bacteria. |
Lactobacillus | A spoilage bacteria that can carry out malolactic fermentation. |
Lees | Sediment from wine fermentation. |
Leuconostoc oenus | The desired bacteria for carrying out malolactic fermentation. |
Malic acid | One of the organic acids found in grapes. |
Malolactic![]() fermentation |
Conversion of malic acid into lactic acid and CO2 gas. |
Mercapton | A compound smelling like cooked green beans. |
Must | The crushed juice, skins, and pulp of grapes. |
Oxidation | Browning and undesirable changes in a wines flavor resulting from contact with oxygen. |
pH | A measurement of hydrogen ions in solution used as an indicator for wine production. |
Potassium![]() carbonate |
A compound that can reduce acidity when added to wine or juice. |
ppm | Parts per million |
Press | A device that extracts juice or wine from grapes. |
Press juice | That fraction of juice or wine separated from the grapes by pressure. |
Paper![]() chromatography |
A test to measure the progress of malolactic fermentation. |
Punching down | Pushing the cap down into the juice during fermentation. |
Racking | Moving juice or wine from one container to another. |
Refractometer | A device to measure the sugar content of juice |
Sulfur dioxide![]() SO2 |
An antiseptic that inhibits the growth of bacteria, acts as an antioxidant, and can be used as a wine preservative and sanitizing agent. |
Stuck fermentation | When a fermentation stops before all of the sugar is converted to alcohol. |
Tannins | Compounds responsible for astringency and bitterness in wine, but also thought to contribute to a wines ability to age. |
Tartaric acid | The main organic acid found in grapes. |
Tartrates | Crystals that can form naturally in chilled wine. |
Topping up | Keeping containers of wine filled to the top to help prevent oxidation. |
Total acidity![]() (TA) |
A measurement of the acid level in wine or juice. |
Total SO2 | The concentration of SO2 in juice or wine that includes both free and bound SO2. |
Yeast | Converts grape sugar to alcohol and CO2 gas. |