Hi i have a glass carboy a friend gave me it is either 6 or 6.5 gallon (he bought it for wine) Can i use this for primary or secondary fermentation? or will it be to big. I will be doing 5 gallon batches.
Should work just fine for five gallon batches, you need the headspace for the krausen, if you tackle some wheat beers you might even need a blow-off tube to help. plus you can watch everything work.
Just be careful on whether you are going to be making 5 gallon American or 5 gallon Imperial.
Check the label or recipe, and should it be for 19 litres, you have a 5 US Gallon recipe... if it's for 23 litres, then its *6* US gallons, or 5 Imperial gallons.
5 US gallons will be fine in the larger carboy, and as people have already noted, might prove beneficial to the beer and your carpet surrounding your beer station