I seem to have lost my reply. I considered fermenting in my new 50 litre barrel to condition it, but it's not in a warm enough place. Primary fermentation usually takes place in a vat. The must is then racked and put in a barrel for the final, far less vigorous stage, then racked after a month, for which you will need another 50 litres of storage capacity. The barrel then needs to be cleaned out and refilled asap, to prevent it drying out. It will also need topping up, to replace the dregs and losses from evaporation, which in itself amounts to 2 litres. What happens next depends on the type of wine. What are you planning to make? Is this a new barrel, and if not, what was it previously used for?