There is described an apparatus (50) for the fermentation of a vegetable product in the form of crushed material, preferentially must, comprising a first tank (62) for containing the crushed material (90) and a second collection tank (54) for the gaseous products generated from the crushed material's fermentation, a first piping system (66) adapted to let communicate a part of the first tank, where the gaseous products are gathered, with the second tank, a second piping system (76) adapted to let communicate the second and the first tank, the system having a outlet in the first tank where, in use, the liquid of the crushed material is present, first and second means a valve (70, 78) associated respectively to the first and second piping system to make the two tanks selectively communicating conditionally to the open/closed status of said means. To allow fermentation in controlled environment there are provided adjustment means (80, 82, 84) adapted to finely adjust the gaseous products pressure to one or more
