Fermentor Size vs Wort Volume

[Mark_B]

Is there such a thing as having too much headspace in your fermentor? I’m wondering if that might be contributing to the oxygenation problem I’m having. I brew about 20L/5gal of wort and it goes into a 30L/8Gal fermentor bucket.

 

[Golddiggie]

I'm typically putting no more than 10 gallons into my 14 gallon capacity conical fermenter without issue. Some batches were about 7-1/2 to 8 gallons going into the conical. No issues for my beers.

How are you packaging your beer? Are you leaving the beer in fermenter (primary) until it gets packaged? IME, there are more ways to oxidize your beer post fermentation than inside primary (or only fermenter for many of us). Many of us also take steps to reduce oxidization risk for our beers once the yeast goes in.

 

[Immocles]

Is there such a thing as having too much headspace in your fermentor? I’m wondering if that might be contributing to the oxygenation problem I’m having. I brew about 20L/5gal of wort and it goes into a 30L/8Gal fermentor bucket.

I regularly ferment 3-4g inside of a 6g fermenter. The only time it has ever been an issue is if I was dry hopping or adding anything during/post fermentation.

 

[Mark_B]

I'm typically putting no more than 10 gallons into my 14 gallon capacity conical fermenter without issue. Some batches were about 7-1/2 to 8 gallons going into the conical. No issues for my beers.

How are you packaging your beer? Are you leaving the beer in fermenter (primary) until it gets packaged? IME, there are more ways to oxidize your beer post fermentation than inside primary (or only fermenter for many of us). Many of us also take steps to reduce oxidization risk for our beers once the yeast goes in.

I don’t do primary/secondary. I just leave it in the fermentor for a couple of weeks and then I bottle. I also bottle directly from the fermentor.

Another brewer mentioned to me on a different thread that I might want to try leaving less headspace in the bottle (?)

 

[hotbeer]

Why do you think it's an oxygenation problem?

Not that it's not, but oxygenation/oxidation tends to get used as a blanket reason too much, IMO.

 

[Elric]

Amount of headspace is realistically only an issue if you are opening up the fermenter during fermentation. If you keep it closed and keep a filled airlock than you will most definitely have purged all oxygen during fermentation. I routinely do 2.5 gallons in a 7+ gallon fermzilla without any oxygen issues, but the fermenter never gets opened until after the beer has been removed.

if you have a lot of empty headspace and either have a leaky seal on your fermenter or are opening it up for samples, additions or just general nosiness than you will be adding oxygen and I can definitely see it causing issues as the extra headspace would increase the amount of oxygen able to get in and mingle with your beer.

 

[McMullan]

No, I don’t think you can have too much headspace in an FV. Too little is usually the problem. I used to ferment 10L batches in 30L FVs without any issues. If you‘ve genuinely got oxidation issues it’s more likely the FV isn’t sealed.

 

[davidabcd]

I brew about 20L/5gal of wort and it goes into a 30L/8Gal fermentor bucket.

That's what I use with no issues and what I like especially is no need for a blow-off tube. You need some but not too much headspace in bottling.
Are you getting the known characteristics of oxygenation?

 

[Golddiggie]

I don’t do primary/secondary. I just leave it in the fermentor for a couple of weeks and then I bottle. I also bottle directly from the fermentor.

Another brewer mentioned to me on a different thread that I might want to try leaving less headspace in the bottle (?)

If you're using a bottling bucket, with the filler wand, following the instructions that typically comes with those things means your headspace (in bottle) is correct. The volume that the wand takes up is used by the yeast to carbonate the beer once bottled (provided you prime it).

 

[DBhomebrew]

Some brewers here on the forum are seeing greater stability while leaving less than the automatic amount of headspace the wand provides. The volume of air is a cushion to absorb thermal expansion of the liquid. Even with absolutely zero room left, the yeast will create CO2 and carbonate the beverage.

 

[davidabcd]

Even with absolutely zero room left, the yeast will create CO2 and carbonate the beverage.

First time I have ever seen or heard this. Where is it from?

 

[DBhomebrew]

First time I have ever seen or heard this. Where is it from?

Put another way, what is the yeast taking from the airspace to create CO2?

 

[davidabcd]

Put another way, what is the yeast taking from the airspace to create CO2?

Thanks. I'm just looking for the reference.

 

[DBhomebrew]

To be clear, I'm not advocating for leaving zero airspace. Just that you don't need it for carbonation to happen. You should definitely leave a minimal amount of space to cushion thermal expansion.

 

[hotbeer]

The volume of air is a cushion to absorb thermal expansion of the liquid. Even with absolutely zero room left, the yeast will create CO2 and carbonate the beverage

Wasn't the OP's question about fermenters? Seems you are talking about bottles and possibly kegs for finished beer.

 

[DBhomebrew]

Wasn't the OP's question about fermenters? Seems you are talking about bottles and possibly kegs for finished beer.

My comment was in response to the one just above my own, which was itself a response to the OP bringing up bottling. Thanks.

 

[ncbrewer]

Another brewer mentioned to me on a different thread that I might want to try leaving less headspace in the bottle (?)

A while back, I started leaving just 1/2" headspace when bottling. It seems to help the hop aroma last longer, but I haven't done a side-by-side comparison.

 

[Mark_B]

That's what I use with no issues and what I like especially is no need for a blow-off tube. You need some but not too much headspace in bottling.
Are you getting the known characteristics of oxygenation?

Not so much a colour shift, but I’m definitely getting a flavour shift from sample to final product.

 

[Mark_B]

Sincere thanks to all of you for trying to help me out. I appreciate all of the advice and suggestions.

Based on the responses, I’m going to see if I can test the seal on my bucket fermentor. And I’ll try to leave a little less headspace in the bottles. Hopefully it’ll solve the issue.

Cheers!

 

[davidabcd]

flavour shift from sample to final product.

While I said it's not the fermenter beer to space ratio, there are other things--leaks, bad caps, for example. With what you've said--bottling directly from the fermenter--shouldn't be an issue, not to the point of off flavors. Someone above mentioned headspace in bottle.
I'm not sure because what you said you do should work.

 

[hotbeer]

I've bottled two or three dozen bottles with maybe a 1/8th inch or less head space and I've also done plenty of them them with the headspace created by removing the filler when the bottled is filled to overflowing. Which is roughly about 1½" from the top.

I've not had issues doing it either way. The benefit to no headspace is more beer per bottle to drink. The only con I've found is you don't get that satisfying pffft when you pop the top.

No need to repeat the cautions, I'm aware of them and I haven't discounted them. But I am slightly skeptical since I've never seen one explode. And I only know people that only claim to know people that have had them.

 

[davidabcd]

And I only know people that only claim to know people that have had them.

You won't see a bottle explode based on your post as far as I'm aware. Your method is not inherently dangerous and would need no cautionary statement. The carbonation that occurs with beer that's reached its proper FG and proper sugar added will never make a bottle bomb.