Fermenting Under Pressure

[Dae Tripper]

I have been shaking the hydo tube heaps but it still releases co2. I might just have to cope...

 

[Dan Pratt]

here is my keg king spunding valve, works great everytime. Set at just over 10psi for fermentation.

 

[bradsbrew]

Mine works well too. And i am fermenting at 22 /23 degres, on purpose. Drinking carbed beer within a week.

 

[Lionman]

The Pacific Ale is now chilling in the kegerator.

Just pitched an El Dorado lager with S189 and a Red IPA with the WLP001 slurry from the previous batch. Hopefully they come out tastey.

The ale is heated with a belt to 20c. The lager seems to be sitting at around 17c. I'll do two ales next and have them both at 22c I think. The White Labs yeasts seem to like slightly warmer temps.

 

[pcqypcqy]

I fill up a schooner glass so I have enough for a sample and a wee taste of my own. To speed up the degassing and warming up I just pour it between two glasses for a while. It does take a little bit of doing to get rid of all the bubbles.

 

[Dae Tripper]

The Pacific Ale is now chilling in the kegerator.

Just pitched an El Dorado lager with S189 and a Red IPA with the WLP001 slurry from the previous batch. Hopefully they come out tastey.

The ale is heated with a belt to 20c. The lager seems to be sitting at around 17c. I'll do two ales next and have them both at 22c I think. The White Labs yeasts seem to like slightly warmer temps.

View attachment 107491

Those temps seem a bit high to me. Like many I target 18c for ales.
I am doing some lagers with Oktoberfest yeast at the moment, starting them off at 11c ish.

But hey if your making nice beer you could tell me to f off and I would be ok with that.

 

[Lionman]

Those temps seem a bit high to me. Like many I target 18c for ales.
I am doing some lagers with Oktoberfest yeast at the moment, starting them off at 11c ish.

But hey if your making nice beer you could tell me to f off and I would be ok with that.

I find the white labs west coast strains get a bit sleepy at 18, prefered range is 20-22. I have brewed with WLP001 and WLP090, both are quite similar. US-05 is ok at 20, slightly cleaner at 18.

I haven't done a a lager before but I chose S189 because a lot of people are saying its very nice at 18. On top of this, pressure supposedly reduces ester production so hopefully it works out. Bit of an experiment with that one.

It really comes down to the specific strain.

 

[Dae Tripper]

It really comes down to the specific strain.

You are spot on there!

 

[malt junkie]

Remember ester production is kept in check by pressure so the couple of degrees to keep the yeast vibrant should have little to no effect on taste.

 

[bradsbrew]

Remember ester production is kept in check by pressure so the couple of degrees to keep the yeast vibrant should have little to no effect on taste.

Can anyone provide a brief explanation as to how pressure does this? I know it does and i am stoked with the results but it does seem wrong.
This beer went into the fermenter Saturday last week and i was drinking it Friday night and kegged it Saturday. Poured another cube of it straight in.

Bit hazy due to 1kg of galaxy at flameout in 100L

 

[Lionman]

Bit hazy due to 1kg of galaxy at flameout in 100L

wow,.. hahaha,.. damn.

edit: actually that's not THAT much for 100L. Equivalent to about 250g or so for a standard batch size.

Can anyone provide a brief explanation as to how pressure does this? I know it does and i am stoked with the results but it does seem wrong.

I think it has something to do with the pressure affecting the yeasts uptake of amino acids which prevents the production of esters. Could be more related to the increased CO2 in solution rather than the pressure itself, not sure on that one.

 

[malt junkie]

Can anyone provide a brief explanation as to how pressure does this? I know it does and i am stoked with the results but it does seem wrong.
This beer went into the fermenter Saturday last week and i was drinking it Friday night and kegged it Saturday. Poured another cube of it straight in.

Bit hazy due to 1kg of galaxy at flameout in 100L

There was a lot of info linked in one of the first threads relating to pressure fermenting. I'll link it if I get the chance later, but interestingly diacetyl (spulling?) production initially sky rockets (compared to standard ferment) but cleans up quicker too, I believe all due to the warmer temps and therefore quicker ferment.

 

[Danscraftbeer]

I don't subscribe to the theory of getting away with warmer temps for pressure fermenting. I've never found a reason to ferment at higher temps. I pressure ferment but starting at the lowest temp range for the yeast. Even lower. The yeast count/pitch rate is the most important in my feeling. Reading others posting notes I often finish my ferments at the temps some people start them at.
For Eg: US-05 I will start as low as 15c and finish at 19c. 20c being the maximum temp that is at the end of fermentation.
$0.02

There is some benefits of the lower temp pressure ferments is that it tames it from needing blow off control etc. Blow off situations with a kegmenter can lead to the gas out blocking and not knowing what the real pressure build up is in the keg. Potentially dangerous. Consider an exploding keg! and the mess I dont ever want to experience so taming the fermentation seems prudent IMO. I may have come close to exploding my 23lt corny kegmenter when hop matter blocked the gas out and who knows what the pressure reached inside. It was a wrangle to release the pressure and got sprayed stout everywhere. Best to tame the big high gravity brews with lower temps.

 

[Lionman]

I don't let any hop matter into the keg when pressure fermenting so that should limit the risk of a blocked gas post. I filter the wort through a hop spider from the cube which does a pretty good job of keeping any chunks out. Only the finest of particles (300 microns) get through and they would be the least likely to cause any issues.

The red IPA is the highest gravity brew I've done yet in the keg at 1.073. No blow off yet. The lager is raging though. Smelling truly sensational.

 

[Dan Pratt]

Im now onto my 4th beer of pressure fermentation. Since the first beer at 23c and 15psi I have toned it back to the std temp of 18c and around 10-11psi.

I will get a much better read of the suppression of the esters when i do my Fake Blonde using W34/70 lager yeast @ 15c. I have done 2 previous batches without pressure in the old coopers FV and they both had estery aroma combined with the dry hop so I will get a real tell sign with that beer for the true effects of the pressure ferment.

 

[malt junkie]

Im now onto my 4th beer of pressure fermentation. Since the first beer at 23c and 15psi I have toned it back to the std temp of 18c and around 10-11psi.

I will get a much better read of the suppression of the esters when i do my Fake Blonde using W34/70 lager yeast @ 15c. I have done 2 previous batches without pressure in the old coopers FV and they both had estery aroma combined with the dry hop so I will get a real tell sign with that beer for the true effects of the pressure ferment.

Don't forget to post results here, it'd be nice to have some real world results with something bright and clean.

 

[Lyrebird_Cycles]

Can anyone provide a brief explanation as to how pressure does this?

Acetyl ester formation (eg amyl acetate, aka banana flavour) is dependent on the level of acetyl CoA and the corresponding alcohol (pentanol in the example given).

High CO2 concentration during ferment reduces biomass formation and thus reduces production of both acetyl CoA and the alcohols. Net result is a reduction of ester formation.

Reference: Renger et al J Inst Brew 1992

 

[rude]

Just keged & drinking APA & very happy used Notto yeast 1052 to 1014 -13
Fermented out the bulk after 3 days so cranked pressure up to 30 psi kegged after 10 days
Tipped another APA on top 1054 to 1012 in 3 days at 5 psi so cranked valve but only got to 10 psi
Checked again 1012 two days later so cc ing to keg only 5 days
Loving the beers from pressure ferment

Does anyone bottle some from the leftovers
I have attached the bottle wand to the bronco tap but getting heaps of foam
A small keg would be good then use carbonation cap

 

[Danscraftbeer]

Does anyone bottle some from the leftovers
I have attached the bottle wand to the bronco tap but getting heaps of foam
A small keg would be good then use carbonation cap

Both Mini Kegs and PET bottles of any size. With the beer transfer lead and still needs to be done under pressure or it goes to froth. Especially if its warm. Actually I would'nt try to bottle warm but you can into a mini keg. Tip is the higher the pressure when transferring the better. If you finished the beer at 30psi then you need to set the co2 bottle to at least 30+ to transfer it.
Only good to bottle cold. Pressurize the PET bottle first, connect beer line, you undo the carb cap (with dip tube) until it hisses to release pressure to fill.

 

[rude]

Wasn't thinking straight
Carb cap straight into Pet Bottles
Cheers