Wine Making Terminology

January 6, 2020

VITICULTURE: The science of growing grapes.

ENOLOGY: The science of winemaking.

VARIETAL: The type of grape, i.e., Cabernet, Merlot, etc.

THE CRUSH:  A process typically done utilizing a crusher-destemmer apparatus.  The procedure strips the berries from the grape clusters, partially breaks the berries and discards the vast majority of the unwanted stems out of the end of the machine.  The fruit and juice fall into large food-grade plastic fermenters.

PRIMARY FERMENTER: An open-top container that holds the fruit after crushing during the primary fermentation process.

THE MUST: The total contents of crushed grapes, juice and residual stems that will undergo primary fermentation.

FERMENTATION: The process that converts most of the sugar in the grapes into alcohol and carbon dioxide gas (CO2).  It is generally a 7-8 day process from the crush to the endpoint of primary fermentation.

DRYNESS: The endpoint of primary fermentation when all of the sugar has been metabolized.

CAP: During fermentation, the production of CO2 gases in the must pushes the grape skins to the top of the primary fermenters forming a dense cap that floats on the lighter liquid. 

PUNCHING DOWN: A procedure done at least three times daily during primary fermentation to prevent oxidation and drying of the cap.  A manual punch down tool is used to break up the cap, rewet the skins, and to push the skins to the bottom of the fermenter.

BRIX: A measurement of the percentage of sugar in the must utilizing an instrument called a hydrometer.  Prior to fermentation, the BRIX reading is generally in an optimum range of 22-25%.  At dryness or the endpoint of fermentation, the BRIX reading is generally 0%. 

YEAST: Grape skins contain natural yeasts capable of allowing fermentation to turn sugar into alcohol.  Yeast is the catalyst that changes grape juice to wine.  In modern winemaking special yeast strains are used specifically to grape varietals ensuring optimum fermentation and extraction advantageous qualities.

TANNIN: A bitter substance contained primarily from grape stems and seeds.  Some components of tannin extraction are desirable for wine complexity and maturity and are assisted by specifically added nutrients.

THE PRESS: The press is a process done for red wine at the end of primary fermentation.  The fermented must is removed from the primary fermenters and placed in a wine press.  The must is compressed mechanically extracting only wine and leaving behind all grape skins and seeds.

SECONDARY FERMENTER: A closed-top fermenter that houses the pressed wine for a few months while malolactic fermentation and clarification take place.

OXIDATION: The combination of air with components of fresh juice or wine.  Oxidation is desirable during primary fermentation, but it is not desirable subsequently as it causes browning and reduces wine quality.

MALOLACTIC FERMENTATION: MLF involves bacteria instead of yeast and it is most desirable for red wines adding a more smooth, round and complex result.  It can be introduced at the late stages of primary fermentation or at the endpoint after pressing.  It changes malic acid to lactic acid.  This process converts any remaining sugar to alcohol and completion of MLF is reached in approximately 3-4 weeks.

THE LEES: During storage in the secondary fermenters particulate debris falls to the bottom of the fermenter by gravity.  This sediment is a chalky substrate containing dead yeast cells and fine organic particulates that periodically are removed from fermenters.

RACKING: This is a pumping or siphoning procedure to periodically clean the bottom of the secondary fermenter of accumulated lees.  This clarifies the wine.  Once the fermenter is cleaned, the wine is pumped back in and re-sealed.  At least 3 rackings are done over a 2-3 month period before the wine is satisfactorily clarified and ready for oak aging.

OAKING: Storage of clarified wine in oak barrels or containers containing oak additives to impart oak flavors to the finished wine.

TOPPING OFF: Adding a similar wine to a vessel/barrel when racking due to evaporation that has reduced its volume.

TA: This is an abbreviation for the total acid of the wine expressed as tartaric acid content.  Wine grapes have three primary acids called tartaric, malic and citric.  In winemaking tartaric is by far more dominant and more important to measure its level (TA), and if necessary, make adjustments.  TA adjustment is one of the more critical and subjective decisions of a winemaker that ultimately determines the flavor desirability of the finished product.

pH: A measure of the intensity of acidity in the juice or wine.  More specifically it measures the concentration of hydrogen ions.  pH is one of the most important variables to track and modify in winemaking.

SULFITING: In winemaking, we use the preservative potassium meta-bisulfite to kill or discourage unwanted wild natural yeasts and to protect the must and wine from harmful bacteria and mold spores.  Without the addition of sulfites wine it would have a short lifespan and develop unpleasant taste characteristics.   The small production winemaker has a decision making advantage to utilize the least amount of sulfites to accomplish adequate taste and protection requirements.