I am a newbie to homebrewing. Up to this point I have always used extracts and fermented in a Mister Beer “keg”. I recently broke the keg while washing it and replaced it with a 3-gallon bucket. It worked OK but I had to use a clamp to keep the lid tight. I will probably continue with 2-3 gallon batches for now but might consider a 5-gallon batch if I like the recipe. What size fermenter should I get? 5 or 6.5 gallon?
If you plan on sometimes doing 5 gal. batches, go for the 6.5. The extra space will be fine for smaller batches, too.
I like the Spiegel 30 L fermenter. It is relatively inexpensive, has a huge airlock and with that size you can do a 5.5 gallon batch with no worry of your wort blowing through the airlock.
I had been down the bucket, carboy, conical road before and this is my go to fermenter.
Get an 8 1/2 gallon wine fermenting bucket if you do 5 gallon batches. I have both but the bigger one doesn’t need a blowoff hose.
My primaries are 6 gal. My first brew needed the blowoff tube, but I was also fermenting a bit warm. Rookie mistake 
My most recent came pretty close to needing the blowoff tube. I actually put it on, expecting that it would be needed (the temp was right on though). The foam came up pretty close, but didn’t make it to where the stopper would have been.
I will likely look into a 6.5 as my next purchase, and maybe sell/give away one of my 6 gal ones.
