Winemaking Terms
While attending OCWS events, you may have overheard us in the Winemakers Group talking “shop.” We tend to use a lot of winemaking terms, familiar to us but maybe not to you. Here are a few of the more common ones. You might also hear them at a winery, if you happen to be visiting during harvest season. These are not listed in alphabetical order but in the order of this very simplified winemaking process.
Viticulture: The science of growing grapes. This is one of the purposes of the OCWS as stated in the by-laws of the organization.
Enology: The science of winemaking, another purpose of the OCWS as stated in the by-laws.
Brix: A measure of the percentage of sugar content in liquids and fruits. In winemaking, brix helps determine grape ripeness and the optimal time to harvest.
Refractometer: A handheld device used to measure brix in grapes before they are picked. A higher brix generally translates to higher alcohol in the finished wine. For white wines, the target brix at which to pick is around 21-22. For red, the general target is 22-24 brix.
Crush & destem: After the grapes have been picked, it’s the process of removing the stems (or stalks) from grape bunches and then piercing the grape skins to release the juice. Although two separate operations, a single piece of equipment (crusher-destemmer) commonly is used to do both at once.
Must: A mixture of crushed grapes, juice, seeds, and skins. Must is the term for this mixture from the time the grapes are crushed and destemmed, until the mixture is pressed.
Hydrometer: An instrument for measuring the brix and specific gravity of a liquid, in this case, the must that will eventually become wine. It’s important to know the initial brix and specific gravity to track the fermentation process and calculate the potential alcohol of the finished wine.
Pitching the yeast: Winemaker slang for adding the yeast to the must to initiate fermentation.
Pressing: When fermentation is complete, it’s the process of squeezing the must to separate the juice from solid material (grape skins and seeds) with a grape press. After the mixture is pressed, the remaining juice is now called wine.
Malolactic Fermentation (MLF): Technically, it’s not a fermentation but a process of converting the malic acid in a wine into lactic acid. The process is induced by the winemaker using special bacteria. The result is a wine with a softer mouthfeel, like the soft and buttery style of California Chardonnay.
Lees: The leftover yeast particles after fermentation which settle on the bottom of the holding vessel and form sediment.
Racking: Transferring wine from one vessel to another to separate wine from the lees and other solids which settle on the bottom. The process is repeated several times until the wine is clear and ready to bottle.
Cheers: Clinking glasses to express goodwill, fellowship and happiness before enjoying wine.
—Ed Reyes, ed@ocws.org