Pressure fermenting temperature

[Ray Porter]

Been thinking about moving to pressure fermenting but only have a small fridge that I use for controlling the temperature in my buckets. I know a pressure system will not fit in it so my question is how important is temperature when pressure fermenting?


Thank you

 

[Sadfield]

Not very. Fermenting under pressure is another way of achieving the same goal as fermenting colder. Raising the dissolved Co2, which inhibits ester production in yeast, resulting in a cleaner fermentation.

This podcast is worth a watch.



https://beersmith.com/blog/2018/01/...s-white-john-blichmann-beersmith-podcast-163/

 

[RoomWithABrew]

However don't let it get to cold either.

 

[Ray Porter]

Thanks for the replies, I'm going to keep my eyes out for a mid sized larder fridge. That should hopefully accommodate a pressure fermenting vessel of some sort.

 

[hoppyscotty]

A pressure system as such is not required...just a pressure capable fermenter and a spunding valve. With the correct yeast selection and pressure then temperature control is not necessary...one of the benefits to pressure fermenting. You can push Kveik yeasts well into the 30's and even into the 40's under pressure, so if you're brewing in the height of summer in a hot country then you're good. And conventional yeasts can be pushed well into the 20's easily.

Though for me pressure fermenting is a tool in the armoury rather than something I do for each and every brew. There are several practical benefits to pressure fermenting, but also some limitations/complications so I pick and choose when I do it to suit the brew. I've yet to find a difference in the flavour of the beer...but practically it is good to have the ability to do it.

 

[RoomWithABrew]

I tend to use pressure capable fermenter, open to start with and spund at the end.
Only lagers done warm do I start with spund set to 15 psi and then build up to 25 to 30 psi.

 

[dtashmore]

I normally ferment at +-16psi then keg directly and get good results, I recently made a dark mild which turned out very good so did exactly the same brew with bread yeast and got exactly the same result when tasted side by side, only difference was the yeast bed which was very loose on the bread yeast, this I think confirms that there is very little esters produced under pressure.

 

[hoppyscotty]

I would love to see a chart like the carbonation chart that shows the pressure and corresponding temperature for different yeasts for best results. The point of pressure is to enable higher fermentation temps to speed up fermentation and prevent the production of off flavours you'd normally get with fermenting hot. So there must be limits to how hot you can go for a given pressure and a point where its no point in going higher pressure or hotter regarding the fermentation speed.

But for now it seems its just a case of a bit of guess work and sussing out what others have experienced success with.

 

[Ray Porter]

I would love to see a chart like the carbonation chart that shows the pressure and corresponding temperature for different yeasts for best results. The point of pressure is to enable higher fermentation temps to speed up fermentation and prevent the production of off flavours you'd normally get with fermenting hot. So there must be limits to how hot you can go for a given pressure and a point where its no point in going higher pressure or hotter regarding the fermentation speed.

But for now it seems its just a case of a bit of guess work and sussing out what others have experienced success with.

Yeah, agreed! That would be an absolute massive help!

 

[Sadfield]

I would love to see a chart like the carbonation chart that shows the pressure and corresponding temperature for different yeasts for best results. The point of pressure is to enable higher fermentation temps to speed up fermentation and prevent the production of off flavours you'd normally get with fermenting hot. So there must be limits to how hot you can go for a given pressure and a point where its no point in going higher pressure or hotter regarding the fermentation speed.

But for now it seems its just a case of a bit of guess work and sussing out what others have experienced success with.

As esters are related to dissolved Co2, then there should be a degree of estimation. Co2 concentration at temperature and pressure is calculable, it's what we use to carbonate kegs.

If you know that a beer fermented at atmospheric pressure at 20°c retains x vols of Co2, then you should be able to adjust the calculation for different temp and pressure for the same result.

 

[hoppyscotty]

I'm sure its calculable, the biggest misconception about brewing beer is that it is 'craft', its is far from that it is pure science and every aspect of it is scientifically explained and generally there is a calculator for every single aspect of the process, which are available to the home brewer with a small amount of research or googling. Just strange that there is not a handy dandy calculator our there for pressure fermenting...yet. I guess for those breweries doing pressure fermenting then they probably go to the effort to go back to first principles and work it out and back it up with some experimentation.

 

[Sadfield]

If you can find an excel version of a force carbonation chart, you could change the temperature values to a more appropriate range, as most top out at 20°c.

 

[phildo79]

Dr Hans used to have an online pressure fermentation calculator but the link stopped working some time ago. It was very useful. You set it by beer style, temperature and desired carbonation level, if I remember correctly.

 

[phildo79]

 

[RoomWithABrew]

Dr Hans used to have an online pressure fermentation calculator but the link stopped working some time ago. It was very useful. You set it by beer style, temperature and desired carbonation level, if I remember correctly.

It was my go to.
This is the nearest replacement, not so user friendly if you want to find out a pressure needed for a desired vol .
Set temp then say you want 3.6 vols you have to enter 6.3 and then .
Very odd.
But it works
https://winning-homebrew.com/force-carbonate.html

 

[hoppyscotty]

Ah, I'm not referring to carbonation but establishing what the optimal temp for a given pressure or pressure for a given temp for the best fermentation.

If you are pressure fermenting to exploit higher fermentation temps for whatever reason, then for that temperature there should, in theory, be an ideal pressure, or at least a minimum pressure. And if you are looking to speed up fermentation then a max temperature for a given yeast beyond which you're not getting any further benefits regarding speed of fermentation is concerned so no point in going hotter - and possibly detrimental to go too far.

Alternatively if you don't have fermentation temp control and live in a hot country and your ambient temp might be high 20's or even into the 30 degrees, then you can establish the best pressure for the temperature the beer will be fermenting at...just would be nice to know what the 'correct' numbers are rather than guessing...just too many combinations and permutations.

I pressure fermented my last batch with S05 and selected 15 psi at 25 degrees C as a complete stab in the dark and partly informed by a question I posted on here...fermentation went pretty well. I held the beer in the fermenter post fermentation longer than I needed because I was away for a week so plenty of time for CO2 to be absorbed, albeit under carbonated for the beer style. I then soft crashed to 15 degrees for dry hop and raised pressure to 20psi to adjust carbonation to the correct level for the beer style, then 3 days dry hop and a couple of days cold crash at 3 degrees and 14 psi before kegging. Resulting beer was perfectly carbonated off the bat. So easy enough to adjust pressure for carbonation after fermentation, especially if you're dry hopping and cold crashing.

However could I have pushed fermentation temp higher? the manufacturer of the yeast doesn't provide any information on pressure fermentation on their website.

 

[Sadfield]

What's optimal though? High fermentation temperature with the least amount of pressure is optimal for yeast health and growth, but not necessarily optimal for beer flavour, unless you want esters and fusel alcohols.

Ah, I'm not referring to carbonation but establishing what the optimal temp for a given pressure or pressure for a given temp for the best fermentation.

If you want to get the ester levels at 25°c that you'd normally get at 19°c without pressure, then you need replicate the conditions that limit ester production. Which is means replicating the levels co2 in solution.

I don't think yeast companies are that interested in pressure fermenting as its contradictory to yeast health and performance. Pressure fermenting as a tool that can be used where temperature control is a problem. If your not constricted by fermenter space like breweries are, have temperature control, then optimal is removing as much pressure as possible, having healthier, happier yeast. Faster lag time, faster fermentation and broader ester profile.

Https://www.google.com/amp/s/brewin...nk-geometry-take-your-beer-to-the-next-level/

 

[RoomWithABrew]

@hoppyscotty I was replying to @phildo79

I don't think that chart will exist unless you make it for your kit and your yeast etc.
Breweries take ages to get their beer right when they scale up. Pressure on yeast will be one factor in large cylindroconical fermenters whether they are capped or not.
I'm not making the same beer time and again at home and have no pressure for consistency like a bug brewery.

 

[Davegase]

Dr Hans used to have an online pressure fermentation calculator but the link stopped working some time ago. It was very useful. You set it by beer style, temperature and desired carbonation level, if I remember correctly.

This is the Dr Hans carbonation calculator that you mentioned and it does still work.
https://www.brewgoat.se/en/pages/digital-kolsyretabell

 

[Omega]

I only did one IPA under pressure and it was so good that finished before conditioning... Lowest temperature was 20.5 Celsius, maximum close to 29 Celsius, and it got there naturally. Thinking I should put my next brew into the garage, the temperature there was well over 20 degress until recent times, but it looks like it will be like this for a while