How much wortis recommended for a 6.5gallon fermentor?

[AKNeal]

Sorry if this has been a repeated topic. I looked for an answer in the forums and couldn't find anything. I am trying to see how much wort I can put with a 6.5 gallon fermentor. I started kegging my beer in a standard 1/6 keg (5.16 gallons). I have only brewed 5 gallon kits and usually end up with somewhere around 4.8+/-. I need to know what the maximum recommended amount of wort you can put in one of these things. I'm thinking about upping my next batch to 6 gallons but I don't want to push it. I want to know if I should just go ahead and buy a couple larger fermenters now. My ultimate goal is to brew 7.5 gallons at a time. Any thoughts?

 

[zachattack]

The thickness of krausen and potential to blow off depends on a zillion factors: OG, yeast strain, temperature, grain bill, hop quantity, etc. I'd say yeast strain is one of the biggest factors. What do you like to brew? For standard American styles with relatively calm yeasts like the Chico variety, you should be able to do 5.5-6 gallons in there easily if you keep the temperature on the cool side. Just rig up a blowoff tube every time. Remember that the 6.5 gallon rating is only up to the place where the glass starts to curve up, it can probably hold 7 gallons when completely topped off.

 

[BigFloyd]

I use 6.5 gallon buckets and fill to no more than 5.3 gallons to leave enough headspace.

 

[ColoHox]

I brew either 6 or 12 gallon batches. My equipment setup (with BeerSmith's help with calculations) means I usually transfer 5.5 gallons of wort into each 6 gallon carboy. In most cases, the fermentation will blow out the airlock, so I almost always use a blow-off.

After fermentation, I usually end up with 5 gallons on the nose, and can fill a keg right up.

7.5 gallons is an odd number why that volume?

 

[AKNeal]

I mainly brew darker ales. I have an oatmeal stout recipe I brew every year. I want to brew 7.5 gallons because I currently brew 5 gallons at a time. The math is easier if I brew exactly 50% more than usual. I don't play around too much with the recipes I try out so it sounds like I'll just have to experiment. Especially with the yeast I use. I currently use the wyeast packets, but I want to start propagating my own yeast soon. My end goal is to have an entire system that's my beer start to finish. No kits or specialty ingredients.

 

[AKNeal]

What about a second airlock? That would allow twice as much gas to escape. It would just be one more thing that is have to keep an eye on.

 

[ColoHox]

What about a second airlock? That would allow twice as much gas to escape. It would just be one more thing that is have to keep an eye on.

It's not just gas pressure, it's krausen overflowing that blows it out.

 

[cluckk]

I use a standard 6.5 carboy and make 5.5 gallon batches. This gives me some for sampling, some that of course gets wasted and I usually end with a full five gallon keg, or very close. I wouldn't put 6 gallons in a carboy. It might work on some, but on many batches it would be way too full and would overflow during high fermentation.

 

[AKNeal]

I see. I will just get the 7.9 gallon buckets now and hope for at least a 6 gallon batch. I may push it to 6.5 just to see if I get an explosive reaction. But that's part of the fun right? Trying new things? Thanks!!