Kolsch fermentation...under pressure or not?

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odie

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Since I've been moving into ferment and serve in the same keg...I'm working out the pressure/spunding bit.

Ales I've found do not like pressure fermentation until after peak krausen in order to let the yeast express properly...especially hefes.

Lagers seem to do just fine with light pressure/spunding at the very start, even at ale temps.

I'm about to do a Kolsch again. But this will be the first time in a corny keg. Since a Kolsch is an ale that is fermented more like a lager (temps and lagering time), my question is can I put in under pressure immediately and even run it at ale temps while under pressure?
 

micraftbeer

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I don't have the answers you seek, but will throw out a data point that might be useful on your search. I have very fond memories of Kolsch fresh from the brewery in Cologne. I've tried to recreate that memory several times and I always get a white-wine like twang to it that I don't like. I've modified recipe, process, and yeast across about 5-6 batches and never been happy.

I decided I'd try fermenting under pressure, in the hopes that the pressure would suppress that unwanted (by me) yeast characteristic. I was using WLP029, and I pitched the yeast at 59F. I left it unpressurized with a blow-off tube for the first 24 hours, and then I dialed up the spunding valve. I then fermented at 60/61F at 15 psi pressure until the beer was finished.

It didn't work. Still had the faint white wine aspect that I didn't enjoy. The 15 psi fermentation didn't seem to dampen out that character.
 

ntempleton

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Imperial Dieter (G03) fermented at 12-12.5c under 12-15psi pressure will get you what you're after. I spent much of last year chasing the Kölsch dragon.
 
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odie

odie

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So kolsch fermented under pressure will be fine? What temps did you ferment at?

I have been using what is labeled/packaged as "Kolsch Yeast". The results have been good unpressurized at 50-55', but I want to try under pressure at ale temps (upper 60s).

I also have K-97 but have not used that strain yet for anything.
 

ntempleton

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So kolsch fermented under pressure will be fine? What temps did you ferment at?

I have been using what is labeled/packaged as "Kolsch Yeast". The results have been good unpressurized at 50-55', but I want to try under pressure at ale temps (upper 60s).

I also have K-97 but have not used that strain yet for anything.

12-12.5c fermentation temperature. Fermenting under pressure is specifically for suppressing the ester profile.

I've not used K-97, so I can't speak to it's performance.
 
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odie

odie

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12-12.5c is lager temp were a "normal" unpressurized kolsch would be at. I'm asking about running kolsch at ale temps, specifically if anyone has done that under pressure to counter any negative affects of that higher fermentation temp.

Is the "ester profile" not desired in a kolsch? In a lager, not desired. I gather a kolsch would be the same. But a kolsch is also kinda an ale/lager hybrid. Putting ales under pressure I've found is counter productive to desired yeast "expression".
 

ntempleton

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12-12.5c is lager temp were a "normal" unpressurized kolsch would be at. I'm asking about running kolsch at ale temps, specifically if anyone has done that under pressure to counter any negative affects of that higher fermentation temp.

Is the "ester profile" not desired in a kolsch? In a lager, not desired. I gather a kolsch would be the same. But a kolsch is also kinda an ale/lager hybrid. Putting ales under pressure I've found is counter productive to desired yeast "expression".
The 3 Kolsch strains I've worked with, G03, 2565, & 029 all express huge amounts of fruit esters. So much so, that I've taken to describing many American Kolsch styles beers as "fruit salad".

Over the course of last year, I experimented with fermentation temps as well as pressure. Cold and full fermentation spunding was required to get the flavor/ester profile that I was after. I've had the pleasure of drinking many a fresh bottle of Kolsch, and I firmly believe that the ester profile has be be muted, to be in line with what is being brewed in Koln currently.
 

Yesfan

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The 3 Kolsch strains I've worked with, G03, 2565, & 029 all express huge amounts of fruit esters. So much so, that I've taken to describing many American Kolsch styles beers as "fruit salad".

Over the course of last year, I experimented with fermentation temps as well as pressure. Cold and full fermentation spunding was required to get the flavor/ester profile that I was after. I've had the pleasure of drinking many a fresh bottle of Kolsch, and I firmly believe that the ester profile has be be muted, to be in line with what is being brewed in Koln currently.


What was the temp and pressure of your profile for your Kolsch? I have a packet of K-97, so may give that a go on a future brew.
 

micraftbeer

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@ntempleton , I have one other detail question on your pressure process. There are variations of process out there on when/how pressure is built up. When I've done my pressurized fermentations, I pitch the yeast, leave the spunding open so no backpressure for the first 24 hours (allowing yeast propagation during lag phase to proceed unhindered), then close the spunding and let it build up to 14 psi. But I've read some people close the spunding right from the start, and some even top off the fermentor with CO2 headspace.

Not trying to open up a debate on the "best" method, just want to recreate your process exactly and see if I get the Kolsch I've been chasing from my flavor memories...
 

ntempleton

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I pitch the yeast, leave the spunding open so no backpressure for the first 24 hours (allowing yeast propagation during lag phase to proceed unhindered), then close the spunding and let it build up to 14 psi.
This my technique as well.

Good luck on your chase, feel free to ask questions.
 
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odie

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I don't think that low of PSI will hinder any yeast propagation. I think it takes a lot more PSI to stop yeast growth. But it will suppress the krausen.
 

wepeeler

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I don't have the answers you seek, but will throw out a data point that might be useful on your search. I have very fond memories of Kolsch fresh from the brewery in Cologne. I've tried to recreate that memory several times and I always get a white-wine like twang to it that I don't like. I've modified recipe, process, and yeast across about 5-6 batches and never been happy.

I decided I'd try fermenting under pressure, in the hopes that the pressure would suppress that unwanted (by me) yeast characteristic. I was using WLP029, and I pitched the yeast at 59F. I left it unpressurized with a blow-off tube for the first 24 hours, and then I dialed up the spunding valve. I then fermented at 60/61F at 15 psi pressure until the beer was finished.

It didn't work. Still had the faint white wine aspect that I didn't enjoy. The 15 psi fermentation didn't seem to dampen out that character.
The 3 Kolsch strains I've worked with, G03, 2565, & 029 all express huge amounts of fruit esters. So much so, that I've taken to describing many American Kolsch styles beers as "fruit salad".

Over the course of last year, I experimented with fermentation temps as well as pressure. Cold and full fermentation spunding was required to get the flavor/ester profile that I was after. I've had the pleasure of drinking many a fresh bottle of Kolsch, and I firmly believe that the ester profile has be be muted, to be in line with what is being brewed in Koln currently.

First off, I'll say I don't ferment under pressure, but I've been chasing the Kolsch dream for a few years now. Took second place at the last local homebrew competition. My first medal :)

I've used WY2565, WLP 029, K-97 and Imperial Dieter. WLP029 is by far my least favorite. I've been fermenting around 60-62, and I never get any fruit salad tasting beer. I've gotten corn, which was 100% my fault. I've since cleaned that up and can make what I think is a pretty damn clean, ester free-ish Kolsch. WYeast 2565 might still be my favorite, but I'm doing another Dieter Kolsch in the next week or so. My yeast preference so far would be 2565, Dieter, K-97, WLP029.

Question on pressure fermenting. Is it only to repress ester formation? Does it help with fermentation at lower temps? I've read that most of these Kolsch yeasts crap out lower than 62, especially on the back end of the fermentation. But I'd love to try a fermentation in the mid-high 50s for comparison.
 

micraftbeer

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<In response to @odie comment that 14 psi wouldn't affect yeast growth>

I have definitely seen fermentation rate slow when fermenting under pressure. Unless you're saying the biological process of the yeast propagating is different than that of yeast consuming wort and making beer, I keep the pressure off.
 

ntempleton

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First off, I'll say I don't ferment under pressure, but I've been chasing the Kolsch dream for a few years now. Took second place at the last local homebrew competition. My first medal :)
Congrats! What competition?

I've used WY2565, WLP 029, K-97 and Imperial Dieter. WLP029 is by far my least favorite. I've been fermenting around 60-62, and I never get any fruit salad tasting beer. I've gotten corn, which was 100% my fault. I've since cleaned that up and can make what I think is a pretty damn clean, ester free-ish Kolsch. WYeast 2565 might still be my favorite, but I'm doing another Dieter Kolsch in the next week or so. My yeast preference so far would be 2565, Dieter, K-97, WLP029.
2565 is my least yeast used Kolsch strain, so I don't have much data for it. I've never used K-97. As with you, WLP029 was also my least favorite yeast - it was the fruitiest of the collection. I've not brewed with K-97, it was the next strain for testing when I decided to stick with Dieter. I might give 2565 another try at some point, just to round my opinion.

Question on pressure fermenting. Is it only to repress ester formation? Does it help with fermentation at lower temps? I've read that most of these Kolsch yeasts crap out lower than 62, especially on the back end of the fermentation. But I'd love to try a fermentation in the mid-high 50s for comparison.
Yes, pressure fermenting (in this case) is specifically about repressing esters. Fermenting at colder temps also helps to repress esters. Both Dieter and WLP029 had no issue fermenting at 12-12.5c (~54 degrees F). That last few Dieter batches fermented so vigorously that I wouldn't have had any concerns about fermenting even cooler. Be sure that you are attentive to yeast health. Good pitching rates being key.
 

wepeeler

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Congrats! What competition?


2565 is my least yeast used Kolsch strain, so I don't have much data for it. I've never used K-97. As with you, WLP029 was also my least favorite yeast - it was the fruitiest of the collection. I've not brewed with K-97, it was the next strain for testing when I decided to stick with Dieter. I might give 2565 another try at some point, just to round my opinion.


Yes, pressure fermenting (in this case) is specifically about repressing esters. Fermenting at colder temps also helps to repress esters. Both Dieter and WLP029 had no issue fermenting at 12-12.5c (~54 degrees F). That last few Dieter batches fermented so vigorously that I wouldn't have had any concerns about fermenting even cooler. Be sure that you are attentive to yeast health. Good pitching rates being key.
New England Brewing Company put on a local comp. Had pro brewers and judges from around the area. I was so happy I was shaking lol.

Well, I got the itch after reading this thread, and I've got 7 minutes left of the mash for another Dieter version. I'm going to ferment this at 58 to see if I can taste a difference. I always read that these Kolsch yeasts don't fully attenuate lower than 60, but I'll take your word for it.

K-97 gave me a brighter tasting Kolsch, but I didn't love it. I got almost a champagne-y, tart flavor. Maybe even a touch of green apple, but not in a bad way. WLP029 was too round. I could not get it to make a crisp Kolsch. Wyeast 2565 makes a great balanced Kolsch, imo. I mashed lower than normal today (147) to try to dry it out the best I can. Fingers crossed!
 
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<In response to @odie comment that 14 psi wouldn't affect yeast growth>

I have definitely seen fermentation rate slow when fermenting under pressure. Unless you're saying the biological process of the yeast propagating is different than that of yeast consuming wort and making beer, I keep the pressure off.
yeast multiplying and yeast eating are two different things.

I read some study (can't recall the source) that seemed to say that the pressure at which yeast stop multiplying was far in excess of the keg burst pressure. Something in the hundreds I think. EDIT>>>my info was wrong, 37 PSI the yeast stops multiplying. around 7,000PSI yeast dies...

As far as a few PSI...5, 10, 15, ? I think all that will do is slow the yeast activity rate "nominally"...meaning slower eating and alcohol making, thus lower krausen. By raising the fermentation temps you restore and/or increase yeast activity beyond what it would have normally been otherwise without pressure, but without the side effects (esters and such).

But I didn't stay in a Holiday Express either...
 
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marc1

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I got a quick tour of Fathead's production brewery earlier this week. They open ferment both their hefe and kolsh.
 

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WYeast 2565 might still be my favorite, but I'm doing another Dieter Kolsch in the next week or so. My yeast preference so far would be 2565, Dieter, K-97, WLP029.

Hey wepeeler, how long does it usually take 2565 to drop out for you? I've been cold crashing a kolsch for over a week now and fined with gelatin, there's still a ton of yeast in suspension. I don't have much experience with this strain..
 

wepeeler

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Hey wepeeler, how long does it usually take 2565 to drop out for you? I've been cold crashing a kolsch for over a week now and fined with gelatin, there's still a ton of yeast in suspension. I don't have much experience with this strain..
I hate Gelatin. Never worked for me. Try Biofine Clear. I'm drinking my Kolsch after 2 weeks primary and a week in the keg. Crystal clear 🍺
 

wepeeler

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Congrats! What competition?


2565 is my least yeast used Kolsch strain, so I don't have much data for it. I've never used K-97. As with you, WLP029 was also my least favorite yeast - it was the fruitiest of the collection. I've not brewed with K-97, it was the next strain for testing when I decided to stick with Dieter. I might give 2565 another try at some point, just to round my opinion.


Yes, pressure fermenting (in this case) is specifically about repressing esters. Fermenting at colder temps also helps to repress esters. Both Dieter and WLP029 had no issue fermenting at 12-12.5c (~54 degrees F). That last few Dieter batches fermented so vigorously that I wouldn't have had any concerns about fermenting even cooler. Be sure that you are attentive to yeast health. Good pitching rates being key.
I'm down to 1.020 at 58F. Should I ramp up yet for D Rest, or wait until 5 points away?
 
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<In response to @odie comment that 14 psi wouldn't affect yeast growth>

I have definitely seen fermentation rate slow when fermenting under pressure. Unless you're saying the biological process of the yeast propagating is different than that of yeast consuming wort and making beer, I keep the pressure off.
I need to correct a previous post I made. It seems yeast stop multiplying at 37 PSI. But death at 7,252 PSI.

 

micraftbeer

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I need to correct a previous post I made. It seems yeast stop multiplying at 37 PSI. But death at 7,252 PSI.

That really sparks my curiosity. What the heck happens in that no man zone between "stop multiplying" and "death"? Are there nuance differences in the biology of what's happening during lag/growth in the presence of pressure, versus fermentation/sugar conversion to alcohol in the presence of pressure? Very interesting.
 
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odie

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well pitched my yeast and set the spunding valve to 10 PSI at 68 degrees. Will see what happens.

BTW, anyone use this yeast? I've done a few Kolsch with it at 55' and been happy. It's a UK sourced yeast. Labeled as a "lager ale" but their website says "top fermenting" which is an ale, as is a Kolsch. The web site also used the term "lager clone" which I assume is how they describe the fermentation process of a true Kolsch, which uses an ale yeast but with lager methods.
20220606_214856.jpg
 

ntempleton

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So you're fermenting just below the recommended temperature range, and with spunding pressure, both of which would tend to make a tougher environment for the yeast. Do you do anything special like a higher yeast pitch rate or higher oxygenation at pitch?
Sorry for the late reply. Yes, I am building properly sized yeast starter (or more often re-pitching from a previous batch) and supplementing O2 post chilling on the way to the fermenter.
 

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Just kegged up the Dieter Kolsch fermented at 58, and so far it smells just fine. I'll grab a taste either later tonight or tomorrow. I like to taste it very early and see how it conditions. I haven't fermented lower than 62 so looking forward to sampling!
 

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Just kegged up the Dieter Kolsch fermented at 58, and so far it smells just fine. I'll grab a taste either later tonight or tomorrow. I like to taste it very early and see how it conditions. I haven't fermented lower than 62 so looking forward to sampling!
Still prefer Wyeast 2565. No question. Dieter is tasting very similar to WLP029. Too malty, yet it finished under 1.010. Not a fan for this style.

2565 > K97 > Dieter > WLP029 IMO. Got Omega Kolsch II in the mail so going to give that a whirl asap.
 

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I have WY2575 that I’ll work into a split batch. I’ve never used it and I think it is similar to 2565. Now that I picked up a freezer this week I can get back to Kolsch brewing.
 

wepeeler

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I have WY2575 that I’ll work into a split batch. I’ve never used it and I think it is similar to 2565. Now that I picked up a freezer this week I can get back to Kolsch brewing.
Didn't know that existed! Yet another Kolsch yeast to try!

Decided I'm going to do a split batch Thursday. 10 gallons, split 2565 and Omega Kolsch II. Just need to hit the local HB shop for more grain now. Ahhhhh
 
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