This fermentation technique is the oldest and still the most widespread method for making red wine. Usually, destemming takes place first to separate the berries from the grape skeletons. The berries are crushed so that their juice can escape. In southern countries, stomping with bare feet is still common to break up the berries in a gentle way. This juice-fruit pulp mixture is called mash. The question of pure or spontaneous fermentation plays a much lesser role than with white wine, since considerably more vineyard yeasts enter the mash with the skins. This means that a good fermentation process (fully fermented) is also possible without problems using natural yeasts. Today's trend is to achieve a colourful, dark red wine with tannins that are as harmonious as possible. The picture on the left shows an open mash fermentation, the picture on the right a red wine marc.
Regardless of the technique, the pomace (solids) floating on top must be constantly mixed or punched down with the fermenting must (French: pigeage, English: punch down) in order to strengthen the extraction. In the past, this was done conventionally by purely manual stirring with wooden sticks. Today, however, mechanical methods are often used, such as overpumping the must onto the pomace, rotating the entire mash in a drum-shaped fermentation container and punching down the pomace using a rotofermenter or autovinification. Permanent contact of the mash with the liquid can also be achieved by screens or similar built into the containers. This prevents the marc cap from rising and it is constantly washed around. This is called the "heading-down system".
Open mash fermentation
Depending on the desired type of wine, the mash fermentation takes place in different fermentation containers. Depending on the fermentation container, a distinction is made between open and closed mash fermentation. Traditional open mash fermentation can take place in fermentation containers made of wood, concrete or...
