How much headspace is too much headspace?

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andyg55

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Hi all

I have 2 fermentors at home for brewing:

1. Plastic bucket (8 gallons)
2. Glass carboy (6 gallons)

I made a 5.5-gallon batch of hefeweizen yesterday and put it in the plastic bucket as I didn't want to fill the glass carboy too high due to the accumulation of foam.

Is a 2-gallon headspace of air ok? Too much? Advice on what is considered too much headspace, as well as too little headspace, would be appreciated.

Cheers,
Andy
 

andyg55

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Are there any guidelines on how big the fermenter should be based on the batch size? I've never found any guidelines.
 

Chippy_Tea

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Is a 2-gallon headspace of air ok? Too much? Advice on what is considered too much headspace, as well as too little headspace, would be appreciated.
I don't brew beer but my view is when fermenting too much head-space isn't an issue as the gap is filled with CO2 too little head-space on the other hand can get messy.

(just my two-penneth happy to be corrected i am wrong)



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Ghillie

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Too much headspace is a myth from over the pond. Those guys prefer messy blow off tubes and/or decorating the ceiling - personally I'm much too lazy for that. Decorating especially.

I ferment 20-23L batches in a 30L bucket. Never an issue and never an oxidised beer from the fermenter.

@Chippy_Tea is right in that the CO2 will probably push all of the air out, even if it doesn't - the CO2 will sink and cover the top of the beer keeping any oxygen away from it.

Relax and enjoy. But be careful with that carboy, they can cause some serious injuries and IMO shouldn't be part of anybody's brewing equipment. Expensive, dangerous and extremely fragile.
 

andyg55

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Superb. Your ratio of 20 L in a 30 L bucket matches my 5.3 gallon in an 8 gallon bucket perfectly. Happy to hear it.

When you urge caution about the carboy, what exactly do you mean? Are you referring to how heavy and fragile they are? (And made of glass?) What do you recommend instead?
 

Ghillie

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Superb. Your ratio of 20 L in a 30 L bucket matches my 5.3 gallon in an 8 gallon bucket perfectly. Happy to hear it.
Excellent. So you must be from the US then if your gallons match my litres?

When you urge caution about the carboy, what exactly do you mean? Are you referring to how heavy and fragile they are? (And made of glass?) What do you recommend instead?
Last year on a Facebook brewing page I saw two instances of brewers smashing glass carboys and cutting themselves to bits. One guy ended up in A&E because he hit an artery. Very lucky man!

The concept of putting 20kg+ in a glass vessel which will ultimately get carried around at some point just makes me cringe. I've never dealt with glass, but understand it's a fantastic material being non porous and easy to clean/difficult to scratch. BUT, I know I'd drop it in some fashion and probably get hurt in the process. Because not only am I clumsy, but I do like a drink when brewing...

Can't see past plastic buckets personally, they don't suck air in and oxidise brews like some maintain - and they're also cheap, easily replaceable and rugged. Stainless is the best you can get though and the only reason I don't yet have a stainless fermenter is because I don't have a fermentation fridge big enough to fit one... Gutted.
 

andyg55

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Excellent. So you must be from the US then if your gallons match my litres?
Originally from the North of England but moved to Vancouver, Canada 5 years ago. It's amazing how quickly you adapt to using American measurements when you're permanently surrounded by them.

I think I'll purchase more plastic buckets... the glass carboys were annoying me anyway.

Interesting experiment, Drunkula. As a novice brewer, I think I'll continue to brew with 1/3 headspace as it doesn't seem to make any obvious difference!
 

Tony Palmer

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Headspace requirements depend on the type of beer and the initial starting gravity. The rule of thumb for ales is a freeboard of 25% and for lagers ( much lower controlled temperature) 10%. There is an exception with some types of rich stout where 40% headspace can be required because of a violent initial fermentation..
 

Covrich

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I have done 12 liters in a 23l fv before, its not ideal but I have yet to have problems.. just leave it to cover itself in a blanket
 

pilgrimhudd

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Same, I regularly do 17-18l batches in my 23l fv, never had a problem with oxidised beer.
 

terrym

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For every molecule of glucose that yeast consumes in the fermentation process, two molecules of CO2 are produced. Or for every 180g of glucose consumed, 88g of CO2 are produced, which is equivalent to about 45 litres of CO2 at ambient conditions. So if you have sugars in wort which will deliver about 2700g of glucose (say 23 litres of a 5-6% ABV homebrew beer) about 675 litres of CO2 will be produced. I suggest that volume is more than enough to purge a few litres of air from the headspace of a standard FV, many times over.
 

johncrobinson

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Ever seen those youtube vids where they top up a demijohn to the neck and start fermenting.

The next part of the vidieo is all about cleaning up the mess :laugh8:
 

Drunkula

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I suggest that volume is more than enough to purge a few litres of air from the headspace of a standard FV, many times over.
Hell yeah! I just used the calculator I made for force carbing with sugar in a separate bottle and 2,600g would force carb 22 litres to 30 volumes. Figure tie in exactly with yours 1 g of sugar makes 1.96 volumes of co2.

And it's something I've actually done - forced carbed 20 litres of beer linked to a 2 litre pop bottle to 2.5 vol with 148g of sugar and it only took about 2 days. I was really surprised it happened so fast, I though it would take maybe a week. The calculator shows the water in the bottle would get to 4.3 abv. I used bread yeast and nutrient. When you rocked the keg you could heard the bubbles going in just like when you're force carbing from a cylinder.
 

eyuptm

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This is what too LITTLE headspace does.... Only pitched this Young's American IPA 24hrs ago, woke to a blocked airlock and a bulging bucket.. Is this normal, or have I got an infection? IMG_20200409_182931.jpg
 

terrym

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@eyuptm
The Youngs AIPA used to be (maybe still is?) known for a very vigorous fermentation at the beginning if you are brewing above 20-21*C and is likely to try to escape the FV as you have found out. So my suggestion is to move it to a cooler place say 18-19*C and it might subside a little. Otherwise you will just have to keep mopping up for a day or two until it dies down.
And to be be clear, assuming you have a good sanitising regime and don't brew beer inside a cow shed you have to be unlucky to get an infection. So please don't fall into the trap of thinking that anything slightly unusual is an 'infection'. Many experienced brewers on this forum have never had one, and of those that have it is usually a rare occurrence
 

eyuptm

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I'm pretty happy with my cleaning/sanitising regime, and there are no funky smells, so I'll just go with it, and mop up every few hours- snot like I'm going anywhere...!!! My ferm fridge is already in use, so that's out the question- might put it in a builders bucket with a towel dipped in the water.. Thanks for your reply!
 

foxy

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You can't have to much head space, as Terry says the amount of co2 given off by fermenting wort I can purge all of my fermenters and kegs. If you haven't got head space some applied pressure will stall the krausen, but that can lead to other problems. As can fermenting at higher temperatures than recommended.
 

eyuptm

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All calmed down now, still bubbling twice a second, but the 'brains' have stopped trying to escape!! I bought 2 fv's when I was in San Francisco, and they're great except for their American gallons, and consequently they're a gallon smaller than ours... Sadly, they've the only ones that fit in my ferm fridge, so am on the lookout for a bigger fridge!! Thanks for your replies!!
 
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