How Much Headspace is Too Much?

[Craigerrr]

Planning ahead to brew smaller batches, and will be doing extract batches when I do.
I have 30L (8 USG) Speidels, will this be too much headspace if I brew 11.5L (3) gallon batches?
My rational brain tells me that it should not matter...

 

[Josh Hughes]

No issues on headspace. Plenty of room to avoid blowouts plus room for a nice fermentation and plenty of extra o2 to begin with. I basically use a 5 gallon keg and ferment 2 or 2.5 gallons. My other is 2 gallons in a 3 gallon fermonster.

 

[Sunfire96]

I think as long as you're not aging the beer for months you'll be fine

 

[Zambi]

Shouldn't be a problem.

I am looking at my 30 litre fermenters (the 10 litre ones are in use) and I had about the same question, except I am looking at a 6 litre batch ( bit less than 2 gallon)

 

[Donoroto]

Maybe 1000:1 is too much. The big issue is if there is enough CO2 to purge the fermenter. 200:1 is crazy but plausible. 10:1 is fine.

 

[Zambi]

I'll give it a try
I'll be 5:1 (roughly). It's going to look silly, but who cares.

 

[GFHomebrew]

Can't remember exactly the numbers but fermentation produces a fair amount of co2 which I'm imagining your concerned about.

 

[Over The Cliff Brewing]

I routinely put 2.5 gallon batches in my Big Mouth Bubblers that are 6.5 gallon capacity. I don't have to worry about blow off tubes no matter the yeast.

 

[Mark Farrall]

I've searched for answers for this question for years. There's a few people that say it's a problem, but it generally just comes across as an opinion. There's a bunch of experiments on fermenter shape or material on Brulosophy that often come back as significant, but last time I checked there wasn't one on too much headspace. So I'm firmly in the maybe camp for this one. It hasn't stopped me using my larger fermenters for smaller batches if there's no free smaller fermenters.

 

[Josh Hughes]

So much co2 you could fill a tank from a fermentation. 3-4 points left f gravity will carb a 5 gallon batch to 2-2.5 volumes.

 

[Ward Chillington]

I've searched for answers for this question for years. There's a few people that say it's a problem, but it generally just comes across as an opinion. There's a bunch of experiments on fermenter shape or material on Brulosophy that often come back as significant, but last time I checked there wasn't one on too much headspace. So I'm firmly in the maybe camp for this one. It hasn't stopped me using my larger fermenters for smaller batches if there's no free smaller fermenters.

I'm in the do it camp. Headspace like this is not an issue for many of the supporting reasons above, rather, too much wort in too tight of a space as in a skinny and tall fermentation tank creates a condition of too much hydrostatic pressure on the yeast. It can damage their cell wall and stifle growth and propagation of the herd.
There are some strains that may have issues with too much CO2, I think it's a sasion strain...something DuPont that does better with an open fermentation setting.

 

[Craigerrr]

Thanks for all of the input folks!

 

[Zambi]

Thanks for all of the input folks!

Hear hear !
I piggy backed on your thread. Thanks for allowing me

 

[NorthWest Small Batch Brewing]

ya I use a 7.5 gal Anvil fermenter with 5 gal batch. the extra headspace means no need for blow off. Plus room to add things like fruit.