History of wine - Other fermentations
Malolactic fermentation
In addition to the fermentation process, a related chemical reaction, known as malolactic fermentation, can take place. It occurs when certain lactic acid bacteria present in grapes react with malic acid, which causes a reduction in the acidity levels of the wine.
The onset of malolactic fermentation is not something that can be predicted, however winemakers try to match it with the alcoholic fermentation that is caused by yeasts. This concept was discovered by Pasteur, but it wasn’t until 1935 that Flanzy achieved the perfect result.
Currently, the process of introducing lactic acid bacteria during fermentation is carried out to obtain lactic fermentation. Three genera classify malolactic bacteria, which are Lactobacillus, Pediococcus and Leuconostoc. Factors that limit malolactic fermentation include temperature (not possible at temperatures below 15°C), the sensitivity of malolactic bacteria to low pH levels, inhibitors (fumaric acid is one of the most notable) and fatty acids (C12 dodecanoic acid is especially effective).
There is a general consensus that the quality of wines improves when controlled malolactic fermentation is used. As a result of this process, the acidity of the wine is reduced and its flavor is altered due to the presence of volatile esters (2,3-butanediol). In addition, some wines may have a buttery flavor as a result of this fermentation.
Second fermentation
The commercial production of sparkling wines began in the early 17th century, when the technology of bottles and cork stoppers had advanced enough to contain the high pressure created by closed fermentation. Among the most famous sparkling wines are champagne, Asti and Cava, as well as other appellations of origin. According to the regulations of the Common Organization of the Wine Market, secondary fermentation in bottles should not be called “champagnes”, “champenoise” or “champenois”.
There are four main alternatives for making sparkling wine: bottled fermentation in the traditional way; the classic method; the traditional method; and the traditional classic method. In English, if wine bubbles are created through natural fermentation, it is often referred to as sparkling wine. If the bubbles are produced by injecting gas, it is known as carbonated wine, or “carbonated sparkling wine” under EU law.
The second fermentation is the one that causes an increase in the concentration of gas, which makes the wine pleasant and bubbly. Other types of wine undergo malolactic fermentation while in the bottle, such as Vinho Verde from Portugal. Since the 19th century, it has been possible to introduce carbon dioxide into wine under pressure, which creates bubbles in a non-traditional way (not from alcoholic fermentation). Normally, these types of carbonated wines are considered to be of lower quality.