A
Acidity: The quality of wine that gives it its crispiness and vitality. The three main acids found in wine are tartaric acid, malic acid and lactic acid. The first two come from the grapes and the third from Malolactic fermentation which often occurs in the winemaking process.
Acidification: Acidification is the process of artificially increasing the acidity of wine with the addition of acids during the process of fermentation. The process of acidification is used to balance the taste of wine when traditional methods are not invasive enough. Wines undergo acidification, usually in warm climates,
to boost up its full-bodied flavor.
Alcohol: Generally refers to ethanol, a chemical compound found in alcoholic beverages. It is also commonly used to refer to alcoholic beverages in general.
Alcoholic fermentation: Alcoholic or ethanol fermentation is the transformation of natural grape sugars into ethanol and carbon dioxide, which turns grape juice into wine. The process of alcoholic fermentation begins shortly after harvest, when large bins of grapes are pressed or crushed to release their juice, making a must. The natural sugars in the must mix with the natural yeast on the grape skins, and alcoholic fermentation begins naturally, however, winemakers add different strains of yeast to the must depending on the style of wine they are making.
Anthocyanin: Phenolic pigments that give red wine its color.
Antioxidant Chemicals: such as sulfur dioxide, that are used to prevent the grape must from oxidizing.
B
Barrel fermented: a wine fermented in oak barrels as opposed to stainless steel or concrete.
Bleeding: also known as the “saignée method”, is one of four winemaking methods for making rosé and a way for winemakers to concentrate the flavor in red wine. The process involves draining the juice from the must so that the phenolics, color and flavors are muted in the juice (which becomes rosé) and concentrated in the must (which becomes red wine). The resulting red wine has more intense characteristics. The juice that runs off is light or bright pink.
Brix: is the unit of measurement used to indicate a grape’s level of ripeness. The level of brix determines the sugar levels and ripeness of grapes prior to and at harvest. Grapes are harvested between 21 and 26 degrees brix. This number also gives the winemaker an estimation of a wine’s potential alcohol from the harvested grapes.
C
Cap: the thick layer of skins, stems and seeds that forms at the surface of fermenting red wine. Cap management, or breaking up the cap to increase contact between the skins and the liquid, is important since red wines extract colour and flavor from the skins.
Carbon dioxide: is a by-product of the fermentation process. During fermentation, the sugar in the grape juice is converted to carbon dioxide and ethanol; for still wines, the carbon dioxide is allowed to escape, however, for sparkling wines, the carbon dioxide is trapped and makes wine effervescent. During fermentation, we know the yeast introduced into the must eats the sugar, converting it to ethanol alcohol, and carbon dioxide is the by-product of this process.
Cold Maceration: cold soaking or Cold Maceration is a technique where freshly picked and de-stemmed berries and juice are kept in a tank at low temperatures (typically about 48 degrees Fahrenheit) for 3-5 days. During the cold soak, the juice and grape skins do not begin fermentation. Cold maceration at 50º F allows the extraction of primary aromas and color. After the berries were placed in the tank dry ice was added to cool down the berries, avoid oxidation and to delay alcoholic fermentation. During the maceration the cap is punched down (twice per day) to keep it wet and the must stirred to ensure even mixing.
Cold stabilization: a winemaking process where wine is chilled to near freezing temperatures for several weeks to encourage the precipitation of tartrate crystals.
Crush: after harvest, and prior to pressing, grape are “crushed” or broken up so that the juice is released and allowed to macerate with the skins prior to and during fermentation. In viticultural terms, “Crush” is used as a synonym for harvest time.
D
Dry: wines with zero or very low levels of residual sugar. Dry is a wine tasting term that describes the tactile, textural feeling of the wine in your mouth. It is the opposite of a sweet wine. A wine is considered dry when the residual sugar level is 4g/L and considered medium dry if the residual sugar level is at 12g/L.
Délestage: French term for racking and returning a wine back to the tank. Wine is pumped out of the fermenting tank and back over the cap to facilitate extraction of color and flavor.
E
Enzyme: a protein created by yeast that act as a bio-chemical catalysts in grape or wine development. An example would be the enzyme invertase which aids the storage of sugars within individual grape berries.
Ethanol: also known as “ethyl alcohol”. The primary alcohol in wine and most other alcoholic beverages. The alcohol content of a wine contributes to its body.
F
Fermentation: a chemical reaction in winemaking. In alcoholic fermentation it is the conversion of sugars to alcohol by yeast while in malolactic conversion it is the conversion of malic acid to lactic by bacteria.
Filtration: the removal of unwanted particles suspended in wine or grape juice.
Fining: a clarification process where flocculants, such as bentonite or egg white, are added to the wine to remove suspended solids. Fining is considered a more gentle method of clarifying a wine than filtering.
Fortification: the process of adding pure alcohol or very strong (77 to 98 proof) grape spirit to a wine. Depending on when the alcohol is added, either before, during or after fermentation, this can result in a wine with a high alcohol content and noticeable sweetness.
Free sulfur: the active element of sulfur dioxide that combined with molecules of oxygen to prevent oxidation. For more details see fixed sulfur above.
Free run juice: juice obtained from grapes that have not been pressed.
L
Lactic acid: the acid in wine formed during the process of malolactic fermentation.
Lees: wine sediment that occurs during and after fermentation, and consists of dead yeast, grape seeds, and other solids. Wine is separated from the lees by racking.
Lees stirring: also known as bâttonage, A process associated with sur lie aging where the lees are stirred up to extract flavor and other sensory components into the wine and to avoid reductive conditions that may contribute to various wine faults.
M
Maceration: is a winemaking process whereby the color, flavor and tannins are transferred from the grape skins to the wine juice, aka must. Macerate literally means “to soften by soaking”; the grape skins are left to soak in their own juices so that they soften and release the qualities that give wines color, body and mouth-feel.
Red wines are allowed to macerate until fermentation is complete. This means that the wines are rich in color. Rosé wines are allowed to macerate for a short period of time, transferring only a little bit of color into the wine which gives it the soft, pink color. White wines are very rarely allowed to macerate. Only varieties with less natural flavor and body structure like Sauvignon Blanc and Semillon.
Malic acid: a strong tasting acid in wine reminiscent of the flavor of green apples. The amount of malic acid in grapes is gradually reduced during the ripening process while the grapes are on the vine and can be further reduced during winemaking by fermentation and malolactic fermentation.
Malolactic fermentation: also known as malo or MLF, a secondary fermentation in wines by lactic acid bacteria during which tart tasting malic acid is converted to softer tasting lactic acid, during which carbon dioxide is generated.
Mannoprotein: a nitrogen rich protein secreted by dead yeast cells during the autolysis process that occur while the wine ages on its lees.
Must: the unfermented juice of grapes extracted by crushing or pressing; grape juice in the cask or vat before it is converted into wine.
O
Oak: the most commonly used wood source for fermentation vessel and barrel aging. Oak influence can also be imparted to a wine by the used of oak chips or staves.
Oxidation: the degradation of wine through exposure to oxygen. In some aspects oxygen plays a vital role in fermentation and through the aging process of wine. But excessive amounts of oxygen can produce wine faults.
P
pH: a measure of the acidity. The lower the pH, the higher the acidity. The term comes from the French Pouvoir Hydrogéne meaning “hydrogen power”. pH is a shorthand for its mathematical approximation: in chemistry a small p is used in place of writing log10 and the H here represents [H+], the concentration of hydrogen ions.
Phenolic compounds: compounds found in the seeds, skins and stalks of grapes that contribute vital characteristics to the color, texture and flavor of wine. Two of the most notable phenols in wine include anthocyanins which impart color and tannins which add texture and aging potential.
Polyphenol: chemical compounds found in plant life. In grapes, polyphenols are responsible for skin pigment, tannins and flavors—all of which fall under the category of flavonoids—as well as resveratrol, the compound associated with many of wine’s health benefits, and which falls under the much smaller polyphenol category of non-flavonoids. Pertaining to wine, grape skins, seeds and stems contain the highest concentrations of polyphenols.
Pomace: the skins, stalks, and pips (seeds) that remain after making wine. Potassium sorbate A wine stabilizer and preservative.
Pressing: after fermentation, the mixture of red grape juice, skins, lees and other solids is pressed to separate the juice from the solids. Because extended skin contact is undesirable for white wines, white grapes are pressed before fermentation.
Press Wine: the juice extracted under pressure after pressing for white wines and after fermentation for reds. Press wine has more flavor and aroma, deeper color and often more tannins than free-run juice. Wineries often blend a portion of press wine back into the main cuvée for added backbone.
Pump Over: a pump-over has the same purpose as a punch-down. By using a pump, wine is pulled from a valve located near the base of a fermentation vat. It is then drawn through the pump into a hose whose end is located at the opening of the vat, where the fermenting juice or wine is then poured or sprayed over the cap.
Punch Down: a punch-down is the process by which the layer of skins, seeds and stems that float above the juice or wine is broken up by submerging them into the liquid during fermentation. It imparts color, aroma, flavor and tannin into the wine which are extracted from the solids. It is carried out manually
R
Racking: a wine is done by pumping wine from its holding or aging vessel into another vat so that it can be removed from the solid particulates, which settle to the bottom. These solids are made up of dead yeast cells, grape skins and much more. Once a wine has finished fermentation, it is moved to a holding tank or barrels where it can be aged. As the wine settles, solids which are normally suspended will precipitate out. These solids are called lees. In the case of red wine, the lees can make the wine bitter. Therefore, red wine is typically racked many times before it is fined and finished. In the case of white wines, they are rarely racked, because these solids add positive characteristics to the wine. White wine is usually only racked after fining and before bottling.
Residual sugar: the unfermented sugar left over in the wine after fermentation. All wines, including those labeled as “dry wines” contain some residual sugars due to the presence of unfermentable sugars in the grape must such as pentoses. It is measured in grams per liter (g/L). A dry wine is usually les than 2gr/lt.
S
Skin contact: another term to describe maceration.
Stabilisation: the process of decreasing the volatility of a wine by removing particles that may cause unwanted chemical changes after the wine has been bottled. In winemaking wines are stabilized by fining, filtration, adding sulfur dioxide or techniques such as cold stabilization where tartrate chemicals are precipitated out.
Sulphur dioxide: SO2 is a preservative and antioxidant used in the winemaking process to prevent oxidation. While its use is considered controversial, this method of preservation has been in use for hundreds of years and can be added at harvest when the grapes are crushed, during fermentation or at bottling. The addition of this compound is done at the preference of the vintner.
Sulfites: winemakers all over the world use sulfur dioxide to clean equipment, kill unwanted organisms on the grapes and protect wines from spoilage. A tiny amount remains in the bottle, and U.S. label laws require a statement to announce its presence. Sulfites also occur naturally during fermentation process.
Sur lie: a winemaking practice that involves prolonged aging on the dead yeast cells (the lees).
Sweetness of wine: defined by the level of residual sugar in the final liquid after the fermentation has ceased. However, how sweet the wine will actually taste is also controlled by factors such as the acidity and alcohol levels, the amount of tannin present, and whether the wine is sparkling.
