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FERMENTING UNDER PRESSURE

Posted: |27 Mar 2015|, 13:18
by jamatron
I recently posted a question to the keg outlet's utube channel about SS brewtech's Chronical fermenter as to whether an air lock or blow off tube was actually needed as the unit comes with a pressure relief spring that vents at 4-5psi. The reply was that you don't want your yeast to ferment under that much pressure. I recall reading that some people on here have fermented/carbonated in cornies just using the natural co2 given off by the fermenting process. If the reply was correct, does anyone have an explanation as to the effects of pressure on fermentation? :S

Re: FERMENTING UNDER PRESSURE

Posted: |27 Mar 2015|, 14:06
by ruf1
I read quite alot about closed fermentation systems a few years back and thought it was great,the use of a spunding valve cotrolled the pressure thats allowed to build up.

Google .closed fermentation sytems or the like and you should find a lot of info.

I had some info on my bookmarks buti cant find it now.........i found it...its on homebrewtalk-search there and find the links that they have.

Hope this helps

:cheers:

Re: FERMENTING UNDER PRESSURE

Posted: |27 Mar 2015|, 14:42
by Doc_Drive
I do that all the time...

The trick is not to have the bulk of the fermentation done under pressure (especially with ales) as it inhibits ester formation.

that said, for lagers I don't ferment under pressure but once a certain amount of FG is reached, I rack into a keg and let the fermentation end there - at the final stages you won't do much harm. If I had a professional fermenter, I'd have it open (with air trap) until a few points above FG and then close the spunding valve and set it to carbonation pressure.

Works like a charm and sticks to the purity law... :)

Re: FERMENTING UNDER PRESSURE

Posted: |27 Mar 2015|, 22:27
by jamatron
Can't argue with the purity law, but ( and maybe im not in the right forum for this question)but :stirpot: if esters are a by product of fermentation which is a chemical reaction does anyone know the effect of pressure on fermentation and what it inhibits or causes.....because if i have to..i'll kick pressure in the face and blame it on my cousin :popcorn:

Re: FERMENTING UNDER PRESSURE

Posted: |27 Mar 2015|, 22:40
by jamatron
I have no quams against pressure...this is a simple mathematic equasion....home brewer + home brewery=...(questions) x (∞)... :wave:

Re: FERMENTING UNDER PRESSURE

Posted: |28 Mar 2015|, 02:33
by Doc_Drive
pressure affects esther formation negatively. higher pressure lower esters. that's why the recommended fermenter for wheat ales are dish bottom open fermenters.

ester production is a biochemical reaction catalyzed by enzymes provided by the yeast. yeast gets stressed under too much pressure and less important functions suffer. ester formation is a less important function. alcohol is a by product from the energy function and therefore still produced, because energy is essential...

Re: FERMENTING UNDER PRESSURE

Posted: |28 Mar 2015|, 13:29
by jamatron
cool, thanks doc!