I brew ten gallon batches, and ferment primary only in 6 gallon buckets. But quite often, I get krausen coming through the airlocks and spill all over my freezer. It’s a pain. I’m thinking 7 gallon buckets would be the way to go.
I use 7 gallon brew buckets when I my 6.5 carboys are busy. I’ve never had any blowouts from one of my buckets. I usually am doing 10 gallon split batches as well.
I’ve never had a blowout when doing 5 gallon batches in my 6.5 gallon bucket. If I were to buy another, I’d go with the 7.9 gallon size that Euge mentions.
I just ordered a bunch of stuff from their site the other day. The only downsides are there’s a $10 fee for orders less than $50, and shipping is not cheap. I haven’t gotten my order yet so I can’t attest to the quality of their products (but a food-grade bucket is a food-grade bucket).
+1. Why not just spend $1 on 2 feet of hose? Fermenting a 5G beer in a 7.9G container leaves a lot of headspace. I’m much more comfortable with a blow off tube than leaving that amount of headspace above my beer.