The principle of pumping over consists of taking the must or the wine from the bottom of a container to return it to the top. This is mainly done by a pumping operation from a tank. It is used for homogenization, oxygenation and especially extraction.

When yeasts convert grape sugar into alcohol, they need to feed themselves (the sugar) but also to breathe.
It is therefore necessary to aerate the wine SEVERAL TIMES A DAY during a good part of the fermentation so that they can take advantage of the oxygen in the air.
In other words, we provide them with assisted breathing.

In this photo, one milliliter of juice contains millions of yeasts!