There are several types of vessels in which the fermentation process can take place. Anything from a small plastic bucket in someones home, to old oak barrels or massive temperature controlled stainless steel tanks. It’s all being done. Here is some more wine-speak around turning juice into wine. (Click here to view part one)
Stainless steel tanks
Most modern wines are today fermented in stainless steel tanks. They certainly have their advantages. It is easier for the winemaker to control the temperature during the process and at the end of it they are easier to clean. It is also a worthwhile investment for those wineries who are doing the volume. Although a large upfront cost, they eliminate the need to replace expensive oak barrels or wooden vessels, which only have a certain life span. Stainless steel tanks can be used over and over again and they provide consistent results.
Wooden vessels & cement vats
Wooden fermentation vessels are still widely used in Europe, and although they don’t have the same longevity as steel tanks, they can be used multiple times depending on the quality. Winemakers prefer old oak for fermentation as it offers natural stabilisation and clarification without adding the overpowering flavours that new oak would bring. Lined cement vats can also be used, some producers believing they provide better aeration than steel tanks.
Maceration & carbonic maceration
Although not a type of (or a tool for) fermentation, this is a very important process for red wine making. Maceration takes place during fermentation. It is the extraction of tannins, as well as the flavour and colouring elements of the solids (grape skins, seeds and stem fragments), into the juice, and depending on the winemakers time constraints it can continue on after fermentation has finished. It is argued by some winemakers that maceration is better done in wooden or cement vats. Carbonic maceration involves maceration without crushing the grape skins. More on that here.
Malolactic fermentation (MLF)
MLF is not technically a process of fermentation but a process of conversion. That is the conversion of the acidic malic acid into the less acidic lactic acid. This is why sometimes an unoaked Chardonnay may still have vanilla/buttery aromas and a creamy texture on the palate. Cooler climate red wines can also benefit from MLF, helping to soften that high natural acidity and bring extra flavour complexities. Ultimately, it all depends on the style the winemaker is trying to achieve, however, care must be taken on to over-do MLF as this can jeopardise the overall balance.
This is essential for sparkling wines. It can either take place in a pressurised tank or in bottle. This article helps explain further.