Quick question to those in the know. Last two batches I have brewed seem to have come out ok but there is virtually no head at all, it doesn't seem flat and there are plenty of bubbles when poured. The thing is the house is old and quite cold so although kept at room temperature before shifting to the cellar could it have been too cold and so stifling carbonation. Now that i'm allowed to put the heating on should I bring it back upstairs and put it in front of the radiators for a few days or is all lost?