Maceration is a big part of red wine making. White wine don't go through that process. If you press red, black or blue grape only white liquid will comes out. To get the wine color you wish, you have to let the skin go through maceration process to give additional taste and color. This is the process I wanted to add to my own wine but I will have to calcualte the amount of sugar versus yeast to make it work. The sugar density can de tested whit hydrometer. In the kit I use to make wine, I have a bag of yeast made for 23liters of wine with a certain sugar density. If I add real grapes and skin it will change this balance. For now I'm studying all about fermentation and maceration to make sure not to make mistake. I found many sites that explain this process.
/from wikipedia/
The process of maceration begins, to varying extent, as soon as the grapes' skins are broken and exposed to some degree of heat. Temperature 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 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 of the skins to come into contact with the wine. During fermentation, higher temperatures and higher alcohol levels can encourage this process with the alcohol acting as a solvent 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 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").
There is 2 new kind of maceration process.
The process of
cold maceration is where temperatures of the fermenting must are kept low to encourage extraction by water and added sulfur dioxide rather relying principle on heat and alcohol to act as a solvent. This technique was popular in the production of Burgundy wines in the 1970s & 1980s but there is still some debate among enologists about the overall benefits and resulting quality of the wine. (This process is good for grapes who are not sweet enough)
Carbonic maceration is the fermentation of whole clusters of unbroken grapes in an atmosphere saturated with carbon dioxide, which prevents traditional yeast fermentation. It is a process different from what is commonly referred to in winemaking as "maceration". (Grapes are but in there intact. The gravity and weight press the juice out and gives color and aroma at the same time.)
