head space

Are there any rules of thumb or more precise formulas to determine how head space affects the pressure of co2 when bottling beer?

I'm trying to figure out things like, hypothetically:

If I had a bottle with 12 ounces of beer and 1 ounce of head space what % of the co2 would be in the beer and what % of the co2 would be in the head space? If I bottle the beer and prime it with the same amount of sugar but leave half the head space (1/2 oz) how does the pressure in the bottle change?

Ultimately I'm wondering, if I leave too little head space, how high can the pressure in the bottle go to?

Thanks for any info or pointers.

Reply to
beerburgerandfrieswithbeer
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If you leave too little head space in the bottle, the beer will not properly carbonate. I don't know why, but it won't.

I use a bottle filler and find when it is withdrawn, there is just the right amount of headspace.

Reply to
Jay Seigfreid

That my be so. Never tried to find out because I use a filler wand too. However, I know when filling 5L mini kegs, T-A-D, or Party Pigs, you need to use about 1/3 less priming sugar to achieve the same results as bottles. I know the percentage of head space on these containers is smaller than that of a 12 oz bottle, but I couldn't say if the smaller amount of priming sugar is due to the larger volume of brew, the smaller percentage of head space, or a combination of the two.

Mark R

Reply to
Mark R

I also use a bottle filler & when filling bottles I try to leave about as much headspace as in the bottles - whether they be stubbies 375 ml or tallies 750 ml - as ( I estimate ) there is when i buy them from the bottleshop. That's worked for me for about

30 years.

I've been kegging for about 15mths now, using 26 litre or 19 litre soda syphon kegs. When I fill the kegs i try to get as little headroom as possible as the kegs will be force carbonated [ ie no priming sugar]. I assume this is the correct way to go.

when bottling a brew i use 2 kegs and 20 to 40 stubbies ( varies due to which kegs used). Each stubby gets one carbonation drop ( sugar ? dextrose glob made by the local home brew shop). Tallies require 2 drops.

Years ago i used to use a cafe-bar dispenser bottle to dispense sugar teaspoon equivalents & i also used spend hours washing bottles

I've had a few explosions over the years . One probable cause would be by accidentally doubling the amount of sugar / dextrose. I think you would have to be in this order of error to make much difference.

Other causes of explosions ( i guess):

- crud on the bottle neck.

- rust on the bottle cap ( i re-use twist-tops )

hth

Ian C

Reply to
Ian Cowan

I've read that this is because the pressure in the bottle builds up too quickly and inhibits the yeast before they can finish carbonating the beer.

Reply to
Beowulf

MDixon (used to be a regular on here) did some experiments a while ago along those lines. IIRC, he found that yeast would remain active up until around 45PSI or so, before they shut down and ceased activity. Can a bottle take that much pressure? I don't know for sure, but it sounds high. I would guess that the bottle would blow before the yeast stopped?

John.

Reply to
John 'Shaggy' Kolesar

I know from an episode of Myth Busters that 3L plastic soda bottles blow up around 90 PSI. Is it reasonable to expect a glass bottle to hold more or less?

I don't know. Glass is thicker, but also more brittle. IIRC, the source for my original statement was one of the Charlie Papazian books. So he may have been speculating at that point.

Reply to
Beowulf

Yeah, those PET soda bottles can take a surprising amount of pressure. IMO, much more than a typical glass beer bottle. Typically, glass becomes "iffy" at anything higher than around 4 volumes of carbonation... whatever PSI that works out to.

I could be entirely wrong here, but atmospheric is what... 14PSI? So 4 volumes of carbonation should be something like 4X that, or 56PSI? In that case... maybe the bottles could take 45PSI and survive.

I've heard lots of theories over the years regarding how (or even if) the amount of headspace effects carbonation. I've never really seen anything that has definitively answered the question though. Lots of speculation, but nothing really concrete.

It does make some sense that an initial burst of pressure build up would halt yeast activity but... Does the pressure really build up that quickly? Carbonation by the yeast is generally a relatively slow process. Also, one would assume that after the initial burst, as the CO2 dissolves into the beer, that the yeast would resume when the pressure drops back down.

John.

Reply to
John 'Shaggy' Kolesar

I've forgotten the names of all the laws and principles to do with the relation between liquids gasses and pressure but I believe the reason for "head space" in an enclosed container is two fold. The first is stability of the contents of the container, the second is that zero head space can cause serious problems with the container. Liquids don't compress and in a container filled 100% even a slight temperature rise could cause a rupture.

With that reasoning if a little yeastie bug has munched on some sugar and wants to fart out a little CO2 he will need some head space for his gas. If there is 0 head space it might cause a compression problem and slow down or stop the yeast from releasing its CO2.

As far as the amount of head space, as I pointed out earlier, there seems to be a relation to the amount of sugar needed to the percentage of head space and the size of the container. I've over filled bottles, and of course there is always the last bottle which seems to get only about 8 oz, but they have all come out with good carbonation. I have never tried a zero head space test as I figured I would get the bottle bomb results.

Mark R

Reply to
Mark R

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