Pressure fermenting

[hoppyscotty]

I've seen plenty of these in UK breweries. 1-2 Bar is 15-29 psi.

https://store.ssvlimited.co.uk/products/spunding-valve

I still maintain its rare in the UK. I've been to two large craft breweries in the last couple of months and, though I didn't get up close to the fermenters I was about 10 - 20feet away and didn't spot any of them with a spunding valve...all fermenters had blow off tubes..and both brewhouses utilised brite tanks too which also suggests no pressure fermentation. These are the things I specifically look for when I do get a chance to cast an eye over a brewery. All the fermenters were enclosed pressure capable conical fermenters, but that makes sense when you're pushing beer around with CO2.

What has a commercial brewery got to gain from pressure fermenting? It's fine for home brewers to do it just for the crack....but what is pressure fermenting doing to improve the beer, or enable them to make it cheaper for a commercial brewery? Most craft breweries I've visited don't have half the gadgets that us home brewers have like hop bongs, so if you're pressure fermenting in a large couple of thousand litre or so fermenter then you're going to have to dump the pressure out of the vessel, drop in your large bags of hops risking the beer gushing up as the hops cause the beer to foam up, then spend more in CO2 to re-pressurise the vessel. failing that you invest in a hopback which is an expensive bit of kit and breweries tend not to be flush with cash and they have to be sure they can get a return on their investment. They can only do that by selling beer for higher prices and make higher margins if they can differentiate it from the competition on the basis of flavour and the market is prepared to pay more, or make the beer cheaper. I'm not sure pressure fermentation achieves any of these things.

I'd be interested to understand why any commercial brewery would choose to pressure ferment during active fermentation.

This is Adam's take on it...



This is interesting too and suggests the main benefit of spunding is to carbonate the beer as it is thought (and I agree) that you get a better quality foam/head when you naturally carbonate vs. force carbonate, which is why I'm experimenting with spunding in the tail end of fermentation.

 

[Sadfield]

Just because the spunding valve goes up to 2 bar doesn't interpret that a brewery bangs the SOP TO 2 bar during fermentation SOP is set when the beer is almost complete usually 1 to2 degrees Plato.

Which in itself would be fermenting under pressure even if it's at the end of fermentation.

I didn't say that having a spunding valve implies that breweries are all banging the pressure straight up to 2 bar. Having one indicates that they've given themselves that option and anything inbetween. Not having one would be the only confirmation that a brewery isn't fermenting under pressure. A quick search on the probrewers forum will reveal there's a wide range of spunding use commercially. Making it perfectly reasonable that some homebrewers may also choose to do it. And possible that good beer can be made under pressure.

Thinking is difficult, that's why most people judge. - Karl Jung

 

[Sadfield]

What has a commercial brewery got to gain from pressure fermenting?

I'd be interested to understand why any commercial brewery would choose to pressure ferment during active fermentation.

This is Adam's take on it...

2:30 in the video you posted. Arbor fermenting a beer at higher temperature but with less esters.

Keeping the krausen down by an amount of top pressure is something I can definitely see commercial breweries doing, less headspace and krausen, more beer and profit.

 

[hoppyscotty]

But less flavour. Just use a bland yeast if you don’t want a flavour contribution from yeast. For example pointless pressure fermenting with something like verdant yeast.

But you’re right for practical stuff like if you’re limited on fermenter headspace and like I said earlier if you don’t have good temp control and have to ferment ant higher temperatures are all good reasons to consider it. But all methods produce results and people will deploy whatever methods they want to for all sorts of reasons, like I’m trying with regards the carbonation at tail end of fermentation.

 

[Andrew Booth]

One of the side effects of pressure fermenting for me is I have to up the quantities of hops in the boil it doesn’t bother me I’m quaffing a nice bitter I brewed three weeks ago at this moment it’s got great aroma and malty sweetness and cascade bitterness which is rapidly becoming one of my favourite hops at the moment.

 

[Sadfield]

But less flavour. Just use a bland yeast if you don’t want a flavour contribution from yeast. For example pointless pressure fermenting with something like verdant yeast.

But what if you wanted to control the esters from Verdant, but keep it's biotransformation properties, soft mouthfeel, body and attenuation? Swapping to something cleaner wouldn't work.

It's just another tool to achieve a desired outcome. Ferment clean beer, faster.

 

[Andrew Booth]

I use a variety of different yeasts without problem I exclusive pressure ferment now tomorrow I’m brewing with WLP013 I’m expecting quite a clean ginger ale off it and again week after next a pseudo lager using lutra kveik which I’ve done before in a pressure fermenter without problems of taste I’ve never looked back since swapping from buckets for brewing

 

[foxy]

Which in itself would be fermenting under pressure even if it's at the end of fermentation.

I didn't say that having a spunding valve implies that breweries are all banging the pressure straight up to 2 bar. Having one indicates that they've given themselves that option and anything inbetween. Not having one would be the only confirmation that a brewery isn't fermenting under pressure. A quick search on the probrewers forum will reveal there's a wide range of spunding use commercially. Making it perfectly reasonable that some homebrewers may also choose to do it. And possible that good beer can be made under pressure.

Thinking is difficult, that's why most people judge. - Karl Jung

They are also a safety aspect majority of tanks have a safe working pressure of 15 PSI though they are tested at 30. They cap the pressure at the end to get some carbonation in the beer. Prior to that there is no top pressure on the ferment, the CO2 is released taking any undesirables with it, H2S, DMS and any oxygen not taken up by the yeast.
Capping a ferment at the start does not release these undesirables which can then lead to further problems.
From Lallemand Yeast.

Ensure a vigorous fermentation to drive off volatile H2S through CO2 stripping and ensure that healthy yeast is present in the beer at the end of fermentation to reabsorb the remaining H2S Strain choice is particularly important for lager strains, which are less vigorous and therefore do not efficiently remove H2S through CO2 stripping. Vigorous fermentations are achieved by pitching a sufficient amount of healthy yeast into a nutrientrich wort and fermenting at an appropriate temperature for that strain. Reabsorption of H2S by the yeast after fermentation is promoted by allowing longer maturation times, especially for lager strains.

 

[foxy]

I still maintain its rare in the UK. I've been to two large craft breweries in the last couple of months and, though I didn't get up close to the fermenters I was about 10 - 20feet away and didn't spot any of them with a spunding valve...all fermenters had blow off tubes..and both brewhouses utilised brite tanks too which also suggests no pressure fermentation. These are the things I specifically look for when I do get a chance to cast an eye over a brewery. All the fermenters were enclosed pressure capable conical fermenters, but that makes sense when you're pushing beer around with CO2.

What has a commercial brewery got to gain from pressure fermenting? It's fine for home brewers to do it just for the crack....but what is pressure fermenting doing to improve the beer, or enable them to make it cheaper for a commercial brewery? Most craft breweries I've visited don't have half the gadgets that us home brewers have like hop bongs, so if you're pressure fermenting in a large couple of thousand litre or so fermenter then you're going to have to dump the pressure out of the vessel, drop in your large bags of hops risking the beer gushing up as the hops cause the beer to foam up, then spend more in CO2 to re-pressurise the vessel. failing that you invest in a hopback which is an expensive bit of kit and breweries tend not to be flush with cash and they have to be sure they can get a return on their investment. They can only do that by selling beer for higher prices and make higher margins if they can differentiate it from the competition on the basis of flavour and the market is prepared to pay more, or make the beer cheaper. I'm not sure pressure fermentation achieves any of these things.

I'd be interested to understand why any commercial brewery would choose to pressure ferment during active fermentation.

This is Adam's take on it...



This is interesting too and suggests the main benefit of spunding is to carbonate the beer as it is thought (and I agree) that you get a better quality foam/head when you naturally carbonate vs. force carbonate, which is why I'm experimenting with spunding in the tail end of fermentation.

Rare in America too, I have visited lots of breweries there and they say the same thing about pressurised fermentation, 'Why would anyone do that' also Pro Brewer has a few posts on it as well.
Each to their own if they think they are making good beer or lager by pressure fermenting from the off by all means do it.

 

[Sadfield]

Each to their own if they think they are making good beer or lager by pressure fermenting from the off by all means do it.

Learn to read @foxy. I've already stated that pressure should be applied after the exponential growth phase has started. I've also never stated a pressure or implied the fermentation is completely closed. Spunding valves work by controlling off gassing, not stopping it completely, meaning volatiles still gas off. How do you think the pressure is created without off gassing? What off flavours do you get from bottle conditioning?

I refer you back to Karl Jung's quote.

 

[foxy]

Learn to read @foxy. I've already stated that pressure should be applied after the exponential growth phase has started. I've also never stated a pressure or implied the fermentation is completely closed. Spunding valves work by controlling off gassing, not stopping it completely, meaning volatiles still gas off. How do you think the pressure is created without off gassing? What off flavours do you get from bottle conditioning?

I refer you back to Karl Jung's quote.

Spunding valves are capped at the end of fermentation as I stated, 1-2 degrees Plato, That way almost all the volatiles have been stripped out of the solution before caping. Provided one has brewed and fermented as above there would be very little off flavours in the finished product when bottle conditioning.
Commercial brewers think more of their yeast bank and finished product rather than get as much wort into the fermenter then cap to suppress the krausen another myth.

 

[Sadfield]

Still ignoring the obvious fact that off gassing of volatiles happens when using a spunding valve at any point. A spunding valve wouldn't work otherwise.

 

[foxy]

Still ignoring the obvious fact that off gassing of volatiles happens when using a spunding valve at any point. A spunding valve wouldn't work otherwise.

No it is you who cannot see the process, a spunding valve for the umpteenth time doesn't come into play until the last couple of points! What is so hard to understand about that. Go and do some brewery visits and ask them!

 

[The Baron]

Just a side question for you pressure guys. Am I right in thinking that the pressure fermenters have a typical life span of 2 years then need to be re-pressure tested or a new one bought.
If so it seems a never ending circle of expense to me that's if it is true?
Just asking

 

[MickDundee]

Just a side question for you pressure guys. Am I right in thinking that the pressure fermenters have a typical life span of 2 years then need to be re-pressure tested or a new one bought.
If so it seems a never ending circle of expense to me that's if it is true?
Just asking

You can pressure test them yourself with gas and some water.

You never test the vessel to its limits anyway so they should last much longer.

 

[Sadfield]

No it is you who cannot see the process, a spunding valve for the umpteenth time doesn't come into play until the last couple of points! What is so hard to understand about that. Go and do some brewery visits and ask them!

That's just one possible process. Fermenting under pressure to consistently control ester and fusel production is another one. What's hard to understand about that.

https://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2001.tb00083.x

 

[Rodcx500z]

Just a side question for you pressure guys. Am I right in thinking that the pressure fermenters have a typical life span of 2 years then need to be re-pressure tested or a new one bought.
If so it seems a never ending circle of expense to me that's if it is true?
Just asking

My 2 reach this stage in August, to be honest i sometime's question why i bought them, the only advantages i can see are, once it is closed that's it until you drink it, it is quicker to ferment out, have i noticed any change in flavour over a plastic bucket no i have not, what will i do after the end date, as they are rated for 35psi and i have never gone over 10psi, i did see a vid were kegland tested one and gave out at 68psi, so based on that i will carry on based on the fact all presser vessels have built in redundency, forgot say they are all rounders and very good very easy to clean i can't fault them in any way, would i buy another no, other than closed transfare which you can with a bucket there is no advantage

 

[Braufather]

I only dry hop after Ferm

I dry hop after fermentation has finished. I have two brew systems...a brewzilla and Fermzilla and a larger 3 vessel system and a stainless conical fermenter

With the smaller system I'll push the beer out of the fermenter and into a purged keg containing the hops so dry hop in the keg off the fermentation trub,then after contact time will push into a serving keg.

On the larger system I'll ferment out, dump trub and then dry hop via a hop bong.

So with the fermzilla will you Pressure carbonate before you dry hop?

 

[Sadfield]

*Commercial brewers are probably brewing under more pressure than you are.

On hydrostatic pressure. c13' in to this 'every 2 feet is a around 1 psi'

 

[crescent city Mike]

Opinions on this subject are rampant. Here's mine . . .
https://crescentcitybrewtalk.com/pressurized-fermentation/