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Primary fermentation CO2 for carbonation?

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cjyh84

Member
Joined
Aug 21, 2012
Messages
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Location
London
Hiya,

so I was thinking, why is it that the co2 produced in primary fermentation is not used for carbonation, and instead is blowed off thru the airlock?

If carbonation occurs when the deadspace in the keg/bottle is saturated with co2, it then has no other choice than to go back down into the liquid and thus carbonating the beer... soooo.. why not for instance ferment in a keg and obviously use no airlock? No more priming bottles or force carbing kegs!

I mean, it sounds sound in theory at least...

Or is this co2 not really used for carbonation because it would make the rest of the process a pain in the ass, eg. dead yeast would be all over the place.. etc. etc...
 
I think the main reason would be how would one
control the vols. of co2 under those conditions.
I would bet with a very rigorous fermentation you would be way over carbonated compared the small amount of sugar you add for priming.

By no means an expert but my 2% of a dollar.
 
hmm yea.. good point..
altho there must be some kind of calculation for co2 volume according to the amount of yeast pitched --i guess-- considering og, temp, etc. etc..

but yea.. it would be too much of a hassle i guess
 
I have the feeling that often the carbonation in British beers is not by priming, but by casking slightly green beer that finishes fermentation / conditioning in the cask. Obviously, the beer has almost finished fermenting as the carbonation is low.
 
I think the cask ale bit is the most likely. I used to make sparkling wine by leting the ferment get abot 80% done,then bottling. The wine was already clear at this point as well. By the time the wine aged sufficiently for drinking (about a year in my case),it was carbnated just like Asti Spumanti. So this could be done with beer as well. But more time in the bottles would be needed to allow it to finish fermenting & trap the co2 in the bottles. Not to mention,conditioning time.
 
When I ferment in a bucket I get 3/4 inch of trub in the bottom when the beer is ready to be bottled. With fermenting in keg that same amount of trub will be in the bottom of the keg right against the pickup tube. I'll bet you'd get some pretty cloudy beer for some time.
 
Check out Close system pressurized fermentation technique for information about this. You will need to ferment in a vessel capable of holding pressure and use a spunding valve (relief valve) to keep the CO2 level appropriate.

This is one of the ideas that I am going to try next year if possible.

That's similar to what some professional breweries do. They capture the CO2 during primary and add it back in later after conditioning.

My concern would be getting rid of the yeast cake and sediment from the fermentation chamber, as others have suggested. Perhaps if you had some sort of conical fermenter/keg with a pickup tube or beer out line somewhere near the bottom but above the sediment line.

To me it sounds easier to just rack from primary into a keg and carb as normal. I agree it's not the most efficient way, but I don't think the specialized equipment that's required to do what you suggest is worthwhile for the ecenomy of scale that the average home brewer works on.
 
That's similar to what some professional breweries do. They capture the CO2 during primary and add it back in later after conditioning.

My concern would be getting rid of the yeast cake and sediment from the fermentation chamber, as others have suggested. Perhaps if you had some sort of conical fermenter/keg with a pickup tube or beer out line somewhere near the bottom but above the sediment line.

To me it sounds easier to just rack from primary into a keg and carb as normal. I agree it's not the most efficient way, but I don't think the specialized equipment that's required to do what you suggest is worthwhile for the ecenomy of scale that the average home brewer works on.

sweet
 
I don't think it's that difficult to pressurize a bit a cask with some fermentation and let the sediment drop below the spigot, but that said, I've never seen one of those keg things and I don't know how you administer the CO2 to them... :D
 
Of course, carbing a cask like you just described is exactly how a real cask ale is handled, but that's different than carbing in the primary fermentation chamber.

Those also use a beer engine to serve. So you still require additional gas to serve. There are those that naturally carb corny kegs and use CO2 to serve, but they still transfer to the keg from the primary.

Side note: does anyone know of a pub-style beer engine that fits a corny keg? That would be a really classy way to serve at my next drinking gathering.
 
As I understood it,beer engines are more of a pump than a co2 pressure feed device. I've seen guys on here setting up beer engines. Try searching for the threads.
 
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