Maceration is the winemaking

Winemaking

Winemaking, or vinification, is the production of wine, starting with selection of the grapes or other produce and ending with bottling the finished wine. Although most wine is made from grapes, it may also be made from other fruit or non-toxic plant material...

 process where the phenolic materials of the grape— tannins, coloring agents (anthocyanins) and flavor compounds— are leached from the grape skins, seeds and stems into the must

Must

Must is freshly pressed fruit juice that contains the skins, seeds, and stems of the fruit. The solid portion of the must is called pomace; it typically makes up 7%–23% of the total weight of the must. Making must is the first step in winemaking...

. Maceration is the process by which the red wine receives its red color, since 99% of all grape juice (with the exceptions of teinturier

Teinturier

Teinturier, a French language term meaning to dye or stain, is a wine term applied to grapes whose flesh and juice is red in colour due to anthocyanin pigments accumulating within the pulp of the grape berry itself. In most cases, anthocyanin pigments are confined to the outer skin tissue only, and...

s) is clear-grayish in color. In the production of white wines, maceration is either actively avoided or allowed in very limited manner in the form of a short amount of skin contact between the must prior to pressing

Wine press

A wine press is a device used to extract juice from crushed grapes during wine making. There are a number of different styles of presses that are used by wine makers but their overall functionality is the same. Each style of press exerts controlled pressure in order to free the juice from the fruit...

. This is more common in the production of varietal

Varietal

"Varietal" describes wines made primarily from a single named grape variety, and which typically displays the name of that variety on the wine label. Examples of grape varieties commonly used in varietal wines are Cabernet Sauvignon, Chardonnay and Merlot...

s with less natural flavor and body structure like Sauvignon blanc

Sauvignon blanc

Sauvignon Blanc is a green-skinned grape variety which originates from the Bordeaux region of France. The grape most likely gets its name from the French word sauvage and blanc due to its early origins as an indigenous grape in South West France., a possible descendant of savagnin...

 and Sémillon

Sémillon

Sémillon is a golden-skinned grape used to make dry and sweet white wines, most notably in France and Australia.-History:The origin of the Sémillon grape is hard to determine. It is known that it first arrived in Australia in the early 19th century and by the 1820s the grape covered over 90 percent...

. For Rosé

Rosé

A rosé is a type of wine that has some of the color typical of a red wine, but only enough to turn it pink. The pink color can range from a pale orange to a vivid near-purple, depending on the grapes and wine making techniques.- Production techniques :There are three major ways to produce rosé...

, red wines grapes are allowed some maceration between the skins and must, but not to the extent of red wine production.

While maceration is a technique usually associated with wine, it is used with other drinks, such as Lambic

Lambic

Lambic is a very distinctive type of beer brewed only in the Pajottenland region of Belgium and in Brussels itself at the Cantillon Brewery and museum...

, piołunówka, Campari

Campari

Campari is an alcoholic apéritif obtained from the infusion of herbs and fruit in alcohol and water. It is a bitters characterized by its dark red color....

 and crème de cassis

Crème de cassis

Crème de cassis is a sweet, dark red liqueur that is made from blackcurrants.Several cocktails are made with crème de cassis, including the very popular wine cocktail, kir.-Origin and production:...

, and also used to steep unflavored spirit with herbs for making herb-based alcohol like absinthe

Absinthe

Absinthe is historically described as a distilled, highly alcoholic beverage. It is an anise-flavoured spirit derived from herbs, including the flowers and leaves of the herb Artemisia absinthium, commonly referred to as "grande wormwood", together with green anise and sweet fennel...

.

Process

The process of maceration begins, to varying extent, as soon as the grapes' skins are broken and exposed to some degree of heat

Heat

In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

. Temperature

Temperature

Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 is the guiding force, with higher temperatures encouraging more breakdown and extraction of phenols from the skins and other grape materials. Maceration continues during the fermentation

Fermentation (wine)

The process of fermentation in wine turns grape juice into an alcoholic beverage. During fermentation, yeast interact with sugars in the juice to create ethanol, commonly known as ethyl alcohol, and carbon dioxide...

 period, and can last well past the point when the yeast has converted all sugars into alcohol. The process itself is a slow one with compounds such as the anthocyanins needing to pass through the cell membrane

Cell membrane

The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...

 of the skins to come into contact with the wine. During fermentation, higher temperatures and higher alcohol

Alcohol

In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

 levels can encourage this process with the alcohol acting as a solvent

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

 to assist in the breakdown of the organic compounds within the grape materials. This process seems to slow once the wine reaches an alcohol level of 10%.

Throughout the fermentation process, carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 is released as a byproduct of the conversion of sugar into alcohol. The carbon dioxide seeks to escape from the must by rising to the top of the mixture, pushing the grape skins and other materials to the top as well. This forms what is known as a cap that is visible on top of the fermentation vessel. At this point, a very limited amount of the must comes into contact with the skins, and winemakers seek to correct this by pushing down the cap (either with equipment or the traditional method of stomping down with their feet) or by pumping wine out from under and over onto the cap. This process of "pumping over" or "punching down" the cap is done often throughout the fermentation process, depending on the extent of maceration the winemaker desires. An efficient and modern method of maceration is the "pneumatage process" in which compressed air or gas is sequentially injected into the juice. The bubble created during the pneumatage process uses gravity and the weight of the juice to circulate the wine juice with the cap of skins and grape solids allowing for greater extraction of aroma, coloring agents and tannins to diffuse into the wine juice ("must").

Benefits

Depending on the varietal, the process of maceration can help bring out many flavors in the wine that would otherwise be lacking. It can enhance the body and mouthfeel

Mouthfeel

Mouthfeel is a product's physical and chemical interaction in the mouth, an aspect of food rheology. It is a concept used in many areas related to the testing and evaluating of foodstuffs, such as wine-tasting and rheology. It is evaluated from initial perception on the palate, to first bite,...

 for many wines, as well as strengthen the color. Greater extraction can add to the complexity and life expectancy of the wine by developing more complex tannins that will soften over a longer period of time. With these benefits does come the risk of developing various wine fault

Wine fault

A wine fault or defect is an unpleasant characteristic of a wine often resulting from poor winemaking practices or storage conditions, and leading to wine spoilage. Many of the compounds that cause wine faults are already naturally present in wine but at insufficient concentrations to adversely...

s, such as the development of acetic

Acetic acid

Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

 (or "volatile") acidity. Too much extraction can also increase the harshness of some tannins to where the wine is not very approachable to most wine drinkers.

Other processes

The process of cold maceration is where temperatures of the fermenting must are kept low to encourage extraction by water and added sulfur dioxide

Sulfur dioxide

Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

 rather than relying principally on heat and alcohol to act as a solvent. This technique was popular in the production of Burgundy wine

Burgundy wine

Burgundy wine is wine made in the Burgundy region in eastern France, in the valleys and slopes west of the Saône River, a tributary of the Rhône. The most famous wines produced here - those commonly referred to as "Burgundies" - are red wines made from Pinot Noir grapes or white wines made from...

s in the 1970s & 1980s but there is still some debate among enologists about the overall benefits to and resulting quality of the wine.

Carbonic maceration

Carbonic maceration

Carbonic maceration is a winemaking technique, often associated with the French wine region of Beaujolais, in which whole grapes are fermented in a carbon dioxide rich environment prior to crushing. Conventional alcoholic fermentation involves crushing the grapes to free the juice and pulp from the...

 is the fermentation of whole clusters of unbroken grapes in an atmosphere saturated

Saturation (chemistry)

In chemistry, saturation has six different meanings, all based on reaching a maximum capacity...

 with carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

, which prevents traditional yeast fermentation. It is a process different from what is commonly referred to in winemaking as "maceration".