# Too Much Headspace?



## Mardoo (17/6/13)

How much headspace is too much during primary fermentation??? I haven't yet found an answer on the forum. 

I want to make a series of 10 liter batches to dial in 3 of my recipes, bottle conditioning the beer. (10 liters so that I have enough to taste over the course of conditioning/development). I brew on a very tight budget and have found some good quality, free 20 liter cubes. I'd love to do small glass carboys but just don't have the dosh. 

Is 50% too much headspace? From the thread below (posts 7 & 8) and subsequent reading it seems that a lot of headspace can lead to greater ester formation. That won't be a problem with two of the recipes, but might be with the third.

http://aussiehomebrewer.com/topic/38426-keg-brew/

I'm primarily (har har) worried about oxidation or other things I don't know enough to worry about yet ;0) I don't currently have the ability to flush the cubes with inert gas, but then I may not need to. 

Can anyone help me with this? Big thanks!


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## JDW81 (17/6/13)

I don't think you need to worry about head space in a home brew setting that much. 50% seems totally fine to me. There are a stack of people who ferment single batches in 50l+ fermenters. The only real risk of oxidation short term is splashing around your wort when transferring from one vessel to another.

As far as the esters go it seems from my reading that this is more a result of temperature and hydrostatic pressure than head space. 

It is also worth remembering that oxygen is very important at the start of fermentation, so you don't want to exclude it completely. It is only bad news once fermentation has really kicked off and at packaging.

JD


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## Mardoo (17/6/13)

Thanks mate!


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## bingggo (24/4/14)

I had a similar question, which led me to this thread 

The Hobart homebrew shop has their own instruction sheet for kits, that says initially fill the fermenter to 3/4 full, then top up to the base of the lid after a few days (or drop in full water bottles) to minimise the headspace for the next 7-10 days while fermentation completes.

But a lot of forum kit recipes, and Coopers website recipes, are for 20-23 litre brews with no concern about the the headspace. The new Coopers fermenter would leave even bigger headspace, of course...

So, I guess the majority vote is headspace isn't anything to worry about... happy to be advised otherwise 

Cheers,
B


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## Bribie G (24/4/14)

When I was short of fermenters a couple of years ago when I carpet bombed the QLD comp but the less said about that the better  - I regularly did a single brew in my 60L fermenter. Compared to the sheer size of the fermenter, and those 60 litres are seriously big buggers, the ferment itself looked quite pitiful, more like the dregs at the bottom of a forgotten coffee cup in a cafe, but it did the job.


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## TimT (24/4/14)

Yeah, biggest problem with a small ferment in a large fermenter - it always looks pathetic.

An episode of Brew TV on open fermentation has a factoid somewhere about lots more esters being formed in an open ferment than a closed one, and in many ways a lot of airspace above beer wort in the process of fermenting would mimic that situation I think.

I did a few saisons in the warmer months, including two quite small runs in an open fermenter. Lots of esters developed. Then again the yeast (Belle Saison) produced esters in the other ones too, so maybe the yeast didn't want much encouragement anyway.


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## Bribie G (24/4/14)

Until the modern industro megaswillbrew era most brewing was done in open fermenters, including Germany, Czechoslovakia and of course the UK.


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## burrster (24/4/14)

my knowledge on this subject isn't that great, but my understanding is that the ferment creates a CO2 layer on top of itself. As it is heavier that air, then the head space size is irrelevant, long as the CO2 'blanket' remains intact. My 2 cents!


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## TimT (25/4/14)

Yes, lots of gas produced, mostly CO2, but also sulfur gases, etc. It's a pretty effective natural blanket for the beer, allowing the yeast to go on with its work unbothered by outside influences. So long as yo don't throw a rat in the brew. After the first two days though the blanket dissipates and it's probably a good time to put a lid on it.


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## Dunkelbrau (3/5/14)

TimT said:


> Yeah, biggest problem with a small ferment in a large fermenter - it always looks pathetic.
> 
> An episode of Brew TV on open fermentation has a factoid somewhere about lots more esters being formed in an open ferment than a closed one, and in many ways a lot of airspace above beer wort in the process of fermenting would mimic that situation I think.
> 
> I did a few saisons in the warmer months, including two quite small runs in an open fermenter. Lots of esters developed. Then again the yeast (Belle Saison) produced esters in the other ones too, so maybe the yeast didn't want much encouragement anyway.


It may sound similar but it isn't by my understanding.

Pressure is related to ester formation in regards to open and closed and pressurised fermentations, open = more because there is no pressure , closed = less because a tiny bit of pressure can build and then pressurised is very minimal, hence why lagers can be brewed at 15-16 degrees commercially.


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