# Fermenting Lagers under pressure



## SJW (20/7/15)

Interesting video in fermenting under pressure. Anyone do it?

https://vimeo.com/44910762


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## Goose (20/7/15)

yes tried it a few times as have a few others.

however as far as I can tell the only benefit is a reduced amount of co2 required when it comes to carbonation time and cannot tell if there are the other purported benefits of a quicker fermentation time, reduced diacetyl and esters.

in fact I found my last batch a real pain to rack to keg given the foaming that occurred so I am definitely not sold on the technique just yet......


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## fraser_john (20/7/15)

Yeah I have had discussions with an ex forum member about doing this, he used to do it all the time when he was brewing. Ferment down to 1.017/15 and then rack into keg with a bit of yeast from the bottom of ferment, seal up and attach spunding valve, ferment till dry then crash to 2c over 5 days and lager. I bought the valve and everything, just never really got around to trying it......


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## fraser_john (20/7/15)

Darn, forgot this as well, I heard (fact or fiction?) that Kolsch is traditionally fermented under pressure, it is part of what gives Kolsch its flavour. Unable to verify though.... and I have el-goog'd the shit out of it.


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## Danscraftbeer (20/7/15)

Save a lot of bottled c02 and/ or priming sugar? I only bottle from keg lately. So they keg it at a certain gravity level. Thats the tricky part. Then leave it to finish out in a sealed keg which will carbonate it as well. Then just chill/lager and drink, or bottle. Intriguing thought but a fine art though. It would be a bit hit and miss with carbonation levels. That could be tweaked after though.


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## dent (20/7/15)

I've been doing it for a few years. I can get away with a warmer ferment later on in the process. Oxygenation is easy and effective - I can pressurise the vessel with air to 40psi or so - the partial pressure of O2 is then excellent. Racking to keg is easy (counter-pressure) and the process keeps oxygen off the beer. Carbonation is free, too, as mentioned.

Only thing that really sucks is cleaning the inside of the fermenter - can't see in there, the only way for a full clean is to fill it with percarbonate or whatever.


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## Danscraftbeer (20/7/15)

Ok here's throwing the thought. Like cubing seems innovative. The idea of a keg as the cube and the primary (can a keg be used as a no chill vessel)?
Then ferment in the keg with an adjustable pressure gage set at the best level. Leave it for --- weeks and chill and serve or bottle?
That seems a pretty nifty trick. Then the flavor judgments etc.


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## dent (20/7/15)

Already have. Works fine.


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## SJW (20/7/15)

Interesting. Not sure it's worth the effort though.


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## wobbly (20/7/15)

SJW said:


> Interesting video in fermenting under pressure. Anyone do it?
> 
> https://vimeo.com/44910762


Yes
All my beers are now fermented under controlled pressure and temperature conditions. The benefits I get are faster ferments for all the beers I have brewed of late - Ales in 7 or 8 days and Lagers/Pilsners in 9 - 10 days from commencement of fermentation to ready for consumption.
My process/equipment does not use a standard keg however the process is basically the same 
As stated in the video you can ferment at higher temperatures and not experience off flavours associated with diacetyl, phenols and some esters
Faster ferments are only one of the benefits that I see. Compared with my previous experiences brewing in a plastic fermenter and then bottling the beers - Cleaner taste, No sediment, No waiting weeks for the carbonation, much smoother/finer carbonation
The video talks about increasing the pressure towards the end of the ferment and then only up to around 10psi. In my situation my equipment allows pressure to build up to 1.5 bar (21psi) from the start of fermentation and then hold that pressure throughout the process to consumption

Wobbly


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## Tahoose (20/7/15)

I did try but I had the pressure gage with valve connected to the keg coupler. I tried to hook it up to 5psi and leave it then ramp it up towards the end.

I won't be doing this again for a while but the plan is for next time:

Start ferment in primary.
Rack to keg with 4-5 points left. 
Carbonate for 3 weeks 
Move keg to fridge and chill
Attach pressure relief valve to desire co2 level(12psi @4c)


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## Danscraftbeer (20/7/15)

Its a great idea but i like to do 40lt brews (2 keg brews) Here's my problem. I rarely make the same beer twice. Final gravity is always a result variable of the estimated FG. You could still pull it off with tweaking the carb later though. I like this idea. It cant be any harder cleaning krausen gunk out of my kegs than the fermenters. Considering you need a variable pressure valve gauge for each keg, Question is: how much are the valves?


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## manticle (20/7/15)

Danscraftbeer said:


> Ok here's throwing the thought. Like cubing seems innovative. The idea of a keg as the cube and the primary (can a keg be used as a no chill vessel)?
> Then ferment in the keg with an adjustable pressure gage set at the best level. Leave it for --- weeks and chill and serve or bottle?
> That seems a pretty nifty trick. Then the flavor judgments etc.


I have tried this. Main issue was the amount of yeast and sediment.

There are workarounds but I was aiming for simplicity so went back to cubing.


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## Danscraftbeer (20/7/15)

Thanks manticle. So I'm thinking a shortened dispense tube for the ferment in keg. Actually I'm thinking on a small scale experimentation its maybe viable, but fiddly. I think I rather getting around to kegging, when I get around to it, rather than kegging at the precise time of gravity levels. that means just letting the beer sit until I get around to it.... -_-


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## manticle (20/7/15)

A shortened dip tube is one of the workarounds although consider the amount of time the beer sits on the trub. Not for long term ageing beers, probably fine for quick drinkers. Give it a whirl and see - there are threads here on the pros and cons, both theoretical and experiential.


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## Cervantes (20/7/15)

I used to do this, but found it more trouble than it was worth. I found the spunding valves that are available very unreliable and difficult to calibrate.

I never noticed and improvement in taste and the gain in free carbonation was offset by the fact that I used to have to use CO2 for a closed keg to keg transfer.

I still ferment in cornelius kegs, but have now fitted them with a tap and pick up tube so that I don't have to syphon or use CO2 for a keg to keg transfer.


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## Tahoose (20/7/15)

Danscraftbeer said:


> Its a great idea but i like to do 40lt brews (2 keg brews) Here's my problem. I rarely make the same beer twice. Final gravity is always a result variable of the estimated FG. You could still pull it off with tweaking the carb later though. I like this idea. It cant be any harder cleaning krausen gunk out of my kegs than the fermenters. Considering you need a variable pressure valve gauge for each keg, Question is: how much are the valves?


Not necessarily, if you have two corny kegs and rack into them at the same time, you could make a beer line with two liquid disconnects and put that on both liquid posts. Then attach your pressure relief valve PRV*. Both kegs would be at the same pressure.

The thing I worked out was that 12psi at 4c worked out to be roughly 26 psi at 18c. My PRV can't handle that, it only goes to 15psi. So the better option would be close the keg, let it fully carbonate, chill and then release pressure to what ever you want. 

I think the PRV can be bought at craftbrewer and keg king. Or you can make your own..


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## dent (21/7/15)

On corny kegs you can turn the pressure relief valve into a spunding valve by replacing the spring with a weaker one.


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## klangers (21/7/15)

Industrially the fermenters are so huge that the wort lower down receives far higher pressure. They do keep some "top pressure" on the fermenters by restricting the output of CO2, however, this is to enable more efficient CO2 recovery rather than faster brewing.

You may be interested to know that Heineken standards require their beer to be brewed in horizontal fermenters to reduce the damage on the yeast caused by hydrostatic pressure from the vertical tanks.


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## Danscraftbeer (21/7/15)

Interesting topic indeed. Good input's brewers B)
Home pressure cooking has some excellent advantages of efficiency of flavor and time so its something that will bug me enough to try this some time, (when I up size the brewery sometime in the future hopefully)..


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