Abstract: A process and vat are disclosed for removing impurity deposits such as fermentation residues, lees and crystallized potassium bitartrate in the preparation of alcoholic beverages such as sparkling wines. After fermentation in a closed standing up vat, fermented liquid containing deposited impurities in the bottom portion of the vat is frozen with a freezing means within the bottom portion of the vat and unfrozen liquid above the frozen liquid is withdrawn. Depositing of impurities in the bottom portion of the vat prior to freezing can be accelerated by cooling the liquid in the vat without freezing so that cooling starts at the top of the vat and progresses towards the bottom.