Lager Fermentation Process

[Pancoastbrewing]

Hello! I've been lager brewing for about two years now. I love it. Made a few really tasty brews (for personal consumption only). I've found that there are lots of different ways to achieve a quality brew, and they don't always "follow the directions" of the various brewing info sites to a T.

Anyway, I'm sort of wondering what everyone else does regarding fermentation processes, in a general way. It seems like my fermentations are awfully fast starters and are generally done in about 10 days. The beers have come out decently well, although with a little acetyldehyde (green apples) note.

I've only made 3 gallon batches, and use two 11g saflager 34/70 dry yeast packets and I rehydrate in some preboiled water. Fermentis suggests cooling the wort to 72F before pitching, which seems awfully warm to me. I then put the carboy in my temperature controlled freezer, set the temp at 52 and I'm done. Initial fermentation activity takes only 5-6 hours...I start seeing bubbles and low krausen within 24 hours and high krausen comes around certainly within 48-72 hours with a fair amount of bubbling in my blow off.

All this seems pretty quick for a lager. I usually hit close to FG within 7-10 days, do a diacetyl rest for 3 days, then lager about 36F. Like I said, my finished beers have been surprisingly good, with a slight green apple taste (although this has dropped off with hardly detectable recently). I've played around with the ferm temp, but I feel like my yeast are getting off to too quickly a start. Comments welcome!

A side note: I brewed a Vienna lager yesterday. I've never seen a fermenting wort look SO CLEAR (see pic). Not sure what to make of this?

 

[RPG27]

I would be interested in hearing people's feedback too.

 

[GrogNerd]

might try Jamil's method, pitching at below fermentation temperature (50°) and letting it rise up to primary (52°)

 

[SanPancho]

You're pitching too warm in my opinion. I'm surprised you don't ha e more off flavors, but I've never used that yeast.

Either do as noted in post above, and be patient as it takes anywhere from 12-36 hours to take off. Or you can pitch a little bit warmer, like 60 or so, and then bring it down towards final ferm temp after it takes off.

Per white labs, esters and off flavors generally don't start showing up for about 12 hours. That's your window to bring temp down into desired range. And since you don't wanna shock the yeast, it's best to stay within about 10 degrees of your desired temp so you don't have to drop too far too fast once activity begins.

 

[Pancoastbrewing]

You're pitching too warm in my opinion. I'm surprised you don't ha e more off flavors, but I've never used that yeast.

Either do as noted in post above, and be patient as it takes anywhere from 12-36 hours to take off. Or you can pitch a little bit warmer, like 60 or so, and then bring it down towards final ferm temp after it takes off.

Per white labs, esters and off flavors generally don't start showing up for about 12 hours. That's your window to bring temp down into desired range. And since you don't wanna shock the yeast, it's best to stay within about 10 degrees of your desired temp so you don't have to drop too far too fast once activity begins.

This is straight from the fermentis website for rehydrating the 34/70 dry lager yeast: "sprinkle the yeast in minimum ten times its weight of sterile water or wort at 23C or 73F. Leave to rest for 15-30 minutes."

I agree, that seems ridiculous, but I do also have trouble cooling the wort below 70.

 

[SanPancho]

I think you're confusing rehydrating the yeast vs pitching it. Yes, dry yeast is rehydrated warm, but I don't think means you should pitch warm like that. Not for lagers. I can't tell you from experience as I don't use that yeast but once you've rehydrated the yeast then you can pitch it into the wort, at which point you shouldn't be too far from final ferm temp.

When they say sterile water or wort, they don't mean your entire fermenter of wort. They still mean rehydrate in little bit of wort, then pitch.

for folks who pitch dry yeast right onto wort, I'm pretty sure it's at desired ferm temp already.

Again, I rarely use dry yeast, and never for lagers, so I don't claim to be the final word here. But I can tell you that the best lager ferments have temp control from start to finish. If you're looking for lager brewing advice, that's about as short and sweet as it gets.

 

[ba-brewer]

I have not done too many lagers, all from starter or repitched yeast except one with w34/70. I rehydrated the yeast then added small amounts of prechilled wort to gently lower the temp before pitching. It did take longer for that batch to get to high krausen compared to batches made from a starter. Funny thing is I repitched the yeast from that batch and it too was slower to start then batches made from starters. No off flavors from either batch.

I guess I use the Jamil method, I normally pitch below 50F and allow it to come up to 50F to start, but I used 53F as that is the stated optimum temp for W34/70. I also noticed they say you go up to 71F so maybe that is why they call for 73F for rehydrating.

 

[iijakii]

Acetal is commonly temp or pitch issues. The fact that you use two packs on a 3gal batch points to temp for me. Not that those two are the only options, but you should try cooling to ferm temps before pitching and seeing how that goes. I believe a lot of the off-flavors are formed during the start of fermentation when they're primarily going under cell-division etc. Fridges can take a long time to cool down a large batch, so you might be a good-chunk of the way through that process by then.

 

[Pancoastbrewing]

Acetal is commonly temp or pitch issues. The fact that you use two packs on a 3gal batch points to temp for me. Not that those two are the only options, but you should try cooling to ferm temps before pitching and seeing how that goes. I believe a lot of the off-flavors are formed during the start of fermentation when they're primarily going under cell-division etc. Fridges can take a long time to cool down a large batch, so you might be a good-chunk of the way through that process by then.

Hmm, I thought acetal was a product of a sluggish ferment, but you're probably right. I need to cool closer to ferm temp next time.

 

[Pancoastbrewing]

I'm at high krausen at the moment, 72 hours after beginning fermentation.

 

[Gavin C]

I think you are confusing the optimal temperature (68F+) for pitching the yeast dry (not rehydrated) with an optimal temperature to minimize the development of unwanted flavors associated with warmer fermentation temperatures. Rehydrate your yeast and this higher pitching temperature is not needed.

That is very warm for pitching IMO. I pitch yeast for my lagers when the wort is cooled to 48F and allow to rise to 50F for the majority of fermentation ti 1-2° Plato above anticipated FG.


I then let the beer temperature passively rise to 68F to allow the yeast to reach FG and some time at the higher temperature for the yeast to metabolize unwanted products created earlier.

With an appropriate pitch-rate and tightly controlled fermentation these metabolites should not be present in any significant quantities.

I then crash cool the beer to 31F, fine with gelatin and keg the beer.

The beer is simultaneously force carbonated and lagered aver the next few weeks at 35F till my patience wears out and I sample the beer.

I like the results I'm getting this way. The time frame from pitching yeast to packaging the beer for my lagers has been 14-16 days so far. Sounds similar to your method.

My Current Lager (Vienna) will be kegged tomorrow.

Fermentation Profile (All in primary no racking despite the labels)


Temperature Ramped when SG is slightly above FG


OG and FG

 

[Pancoastbrewing]

That is very warm for pitching IMO. I pitch yeast for my lagers when the wort is cooled to 48F and allow to rise to 50F for the majority of fermentation ti 1-2° Plato above anticipated FG.

I think you are confusing the optimal temperature (68F+) for pitching the yeast dry (not rehydrated) with an optimal temperature to minimize the development of unwanted flavors associated with warmer fermentation temperatures. Rehydrate your yeast and this higher pitching temperature is not needed.

I then let the beer temperature passively rise to 68F to allow the yeast to reach FG and some time at the higher temperature for the yeast to metabolize unwanted products created earlier.

With an appropriate pitch-rate and tightly controlled fermentation these metabolites should not be present in any significant quantities.

I then crash cool the beer to 31F, fine with gelatin and keg the beer.

The beer is simultaneously force carbonated and lagered aver the next few weeks at 35F till my patience wears out and I sample the beer.

I like the results I'm getting this way. The time frame from pitching yeast to packaging the beer for my lagers has been 14-16 days so far. Sounds similar to your method.

My Current Lager (Vienna) will be kegged tomorrow.

Fermentation Profile (All in primary no racking despite the labels)
View attachment 313009

Temperature Ramped when SG is slightly above FG
View attachment 313011

OG and FG
View attachment 313010

Very good info. Perhaps my three day diacetyl cleans up some of the unwanted byproducts of starting too warm. I will have to do a better job of cooling after the boil. It just seems to take too long (and I do use an immersion chiller). Probably 30 minutes and I only have 3 gallons to cool. I just seem to hit a wall at about 70F and I get impatient and pitch the rehydrated yeast. I seem to get great clarity and color and decent head/lacing with the way I've been doing it. Would like to remove that slight apple smell though.

 

[brian320fo]

+1 on Gavin C's reply.

Rehydrate the yeast at 72* and let it sit at that temp for 30 minutes. Then cool the yeast in the fridge until it has reached 48* at which time you can pitch it into your 48* wort. This helps prevent shocking the yeast by just dumping 72* yeast into 48* wort. Not rehydrating the yeast or pitching it into to warmer wort then cooling the wort after pitching are not the best options. I also would not rehydrate in cooled wort, use sterilized water only.

 

[Pancoastbrewing]

+1 on Gavin C's reply.

Rehydrate the yeast at 72* and let it sit at that temp for 30 minutes. Then cool the yeast in the fridge until it has reached 48* at which time you can pitch it into your 48* wort. This helps prevent shocking the yeast by just dumping 72* yeast into 48* wort. Not rehydrating the yeast or pitching it into to warmer wort then cooling the wort after pitching are not the best options. I also would not rehydrate in cooled wort, use sterilized water only.

Good tips. Why would you not rehydrate in the cooled wort? Just curious.

 

[Pancoastbrewing]

That is very warm for pitching IMO. I pitch yeast for my lagers when the wort is cooled to 48F and allow to rise to 50F for the majority of fermentation ti 1-2° Plato above anticipated FG.

I think you are confusing the optimal temperature (68F+) for pitching the yeast dry (not rehydrated) with an optimal temperature to minimize the development of unwanted flavors associated with warmer fermentation temperatures. Rehydrate your yeast and this higher pitching temperature is not needed.

I then let the beer temperature passively rise to 68F to allow the yeast to reach FG and some time at the higher temperature for the yeast to metabolize unwanted products created earlier.

With an appropriate pitch-rate and tightly controlled fermentation these metabolites should not be present in any significant quantities.

I then crash cool the beer to 31F, fine with gelatin and keg the beer.

The beer is simultaneously force carbonated and lagered aver the next few weeks at 35F till my patience wears out and I sample the beer.

I like the results I'm getting this way. The time frame from pitching yeast to packaging the beer for my lagers has been 14-16 days so far. Sounds similar to your method.

My Current Lager (Vienna) will be kegged tomorrow.

Fermentation Profile (All in primary no racking despite the labels)
View attachment 313009

Temperature Ramped when SG is slightly above FG
View attachment 313011

OG and FG
View attachment 313010

I replied to you but it didn't show up. Thanks for the info. I think my d-rest has been helping to cover up some of my "too warm to start" problems. Clarity, color and head retention have been pretty good. I'm just trying to remove that slight apple juice smell. Starting cooler would probably help. Is 22g dry yeast too much for a 3 gallon batch at 1.052?

 

[Gavin C]

Good tips. Why would you not rehydrate in the cooled wort? Just curious.

For lagers you really want to stack the deck in your favor. A big fat healthy dose of yeast and a cool pitching temperature seem to be a part of this stacking process.

Pitching directly into wort without first rehydrating will kill a lot of your yeast. That is not in doubt if the science is to be believed. The question remains; is this cell death going to have an impact on the beer's characteristics? For a 3 gallon batch and two packs you are in all likelihood still in good shape.

This link does not answer your question but does explore rapid temperature changes with dry yeast. i found it interesting and somewhat relevant to the discussion.

Regarding the cold temperature of dry pitching I am still looking. Here are some good videos from a lab discussing the process for dry yeast in commercial batches of wine. The first two videos mention cold shocking. Some homework needed on my part to learn more about this.

 

[gometz]

I will usually cool my wort to 60 and then place it in the fridge at 48 overnight or 24 hours before pitching. I'll leave the starter in the fridge with the wort to allow it to crash. Right before pitching I aerate the wort using an air stone for a few minutes, then pitch the decanted starter.

I have had good experience going this route. I also use the quick lager method which so far has worked very well for me (much better than I ever expected).

 

[Pancoastbrewing]

For lagers you really want to stack the deck in your favor. A big fat healthy dose of yeast and a cool pitching temperature seem to be a part of this stacking process.

Pitching directly into wort without first rehydrating will kill a lot of your yeast. That is not in doubt if the science is to be believed. The question remains; is this cell death going to have an impact on the beer's characteristics? For a 3 gallon batch and two packs you are in all likelihood still in good shape.

This link does not answer your question but does explore rapid temperature changes with dry yeast. i found it interesting and somewhat relevant to the discussion.

Regarding the cold temperature of dry pitching I am still looking. Here are some good videos from a lab discussing the process for dry yeast in commercial batches of wine. The first two videos mention cold shocking. Some homework needed on my part to learn more about this.

So much science involved!

 

[C-Rider]

Interesting talk about pitching temperatures....For the one and only lager I've done I cooled the wort over night to about 54*F and then pitched a whole pack of SafLager S-23 yeast which was kept in my fridge along w/all house hold food temp. I did not re-hydrate as I never do w/ales and never had a carbonation problem. The beer finished just fine going from 1.063 to 1.015. The only problem is that after weeks already its not carbonated. It tastes great, just flat. Oh yea this is a 2 gallon batch.

 

[SanPancho]

If you want to get to pitch temp with your chiller, you prolly will need to use ice water, it sounds like your ground water is too warm. I got a cheap $8 pond pump on Amazon and use an ice water bath pumped thru chiller coil if I want to get down to pitch temp in a hurry.

One thing to note is that if you really like clear beer, that putting the kettle into the fridge overnight does wonders for causing trub to collect and compact at bottom of kettle. It gets the wort Amazingly clear, all by letting it settle and cool overnight.

 

[brian320fo]

Good tips. Why would you not rehydrate in the cooled wort? Just curious.

The purpose of rehydrating the yeast is to get water to cross through the cell wall and into the cell. Wort has a lot of sugar in it. Even though there are more water molecules than sugar molecules in wort, the sugar molecules exert more pressure on the cell wall than water molecules do. This gives sugar about a 30% - 50% chance (depending on OG) to get through the cell wall before water does. If this happens it usually kills the cell. So. if you pitch directly, unless you compensate for the loss of yeast cells, you're probably under pitching by 30% - 50%. Treat your yeast with respect!

 

[Pancoastbrewing]

The purpose of rehydrating the yeast is to get water to cross through the cell wall and into the cell. Wort has a lot of sugar in it. Even though there are more water molecules than sugar molecules in wort, the sugar molecules exert more pressure on the cell wall than water molecules do. This gives sugar about a 30% - 50% chance (depending on OG) to get through the cell wall before water does. If this happens it usually kills the cell. So. if you pitch directly, unless you compensate for the loss of yeast cells, you're probably under pitching by 30% - 50%. Treat your yeast with respect!

Great info. Thanks.

 

[Pancoastbrewing]

If you want to get to pitch temp with your chiller, you prolly will need to use ice water, it sounds like your ground water is too warm. I got a cheap $8 pond pump on Amazon and use an ice water bath pumped thru chiller coil if I want to get down to pitch temp in a hurry.

One thing to note is that if you really like clear beer, that putting the kettle into the fridge overnight does wonders for causing trub to collect and compact at bottom of kettle. It gets the wort Amazingly clear, all by letting it settle and cool overnight.

The ground water just might be too warm. It cools super super slowly once it hits about 80. I can't imagine how long it would take to get to 50. I live in northern PA, I'm surprised I'm having that issue.

 

[SanPancho]

The ground water just might be too warm. It cools super super slowly once it hits about 80. I can't imagine how long it would take to get to 50. I live in northern PA, I'm surprised I'm having that issue.

Yeah, that's definitely surprising. I'm in San Francisco and our water is typically 55. But once I get to the 70s it slows way down. So that's why I typically use ice, or just wait till next morning to pitch.

For simplicity sake, I'd say just put it in fridge and wait. If you leave it in the kettle you'll siphon or rack off cleaner beer, and if you aerate with oxygen, cold liquid absorbs gas better than warm liquid so your yeast will do better from the get-go. It's just one more way to set yourself up for clean fermentation from lager yeast.

 

[Pancoastbrewing]

Yeah, that's definitely surprising. I'm in San Francisco and our water is typically 55. But once I get to the 70s it slows way down. So that's why I typically use ice, or just wait till next morning to pitch.

For simplicity sake, I'd say just put it in fridge and wait. If you leave it in the kettle you'll siphon or rack off cleaner beer, and if you aerate with oxygen, cold liquid absorbs gas better than warm liquid so your yeast will do better from the get-go. It's just one more way to set yourself up for clean fermentation from lager yeast.

I was always under the impression that time was of the essence when chilling the wort. I would hate to think of all the horrible things that could go wrong when leaving the kettle in my fridge for a few hours. My roommate would probably drink it.

 

[Gavin C]

I was always under the impression that time was of the essence when chilling the wort. I would hate to think of all the horrible things that could go wrong when leaving the kettle in my fridge for a few hours. My roommate would probably drink it.

Thirsty roommates aside, delaying pitching till the wort is at the target temperature you want is entirely routine for many brewers including lots who do no chill brewing. Delaying things is not a problem assuming your sanitation is as it should be.

My chilling process.

Wort is chilled from boiling to ~65-75F depending on the time of year. In summer I use a pre-chiller in addition to my plate-chiller. This takes ~10 minutes for my 5.5 gallon batches.

Prechiller


After transfer to the FV the wort is oxygenated and placed in the fermentation chamber till the desired pitching temperature is reached (48F for lagers, 54F for hybrids, 62F for ales. This typically takes anywhere from 2-6 hours.

Oxygenation


The yeast is then pitched and the controller set to the desired fermentation temperature +/- 0.3C measuring the beer temperature throughout.

 

[Pancoastbrewing]

Thirsty roommates aside, delaying pitching till the wort is at the target temperature you want is entirely routine for many brewers including lots who do no chill brewing. Delaying things is not a problem assuming your sanitation is as it should be.

My chilling process.

Wort is chilled from boiling to ~65-75F depending on the time of year. In summer I use a pre-chiller in addition to my plate-chiller. This takes ~10 minutes for my 5.5 gallon batches.

Prechiller
View attachment 313171

After transfer to the FV the wort is oxygenated and placed in the fermentation chamber till the desired pitching temperature is reached (48F for lagers, 54F for hybrids, 62F for ales. This typically takes anywhere from 2-6 hours.

Oxygenation
View attachment 313172

The yeast is then pitched and the controller set to the desired fermentation temperature +/- 0.3C measuring the beer temperature throughout.

Your beer must be amazing. Great work.

 

[Gavin C]

Your beer must be amazing. Great work.

Too kind words mate. Thanks. I am of course biased as most of us are when it comes to our own creations. I must admit to enjoying my beer and really enjoy the process and the added challenges that lager brewing brings.
I wish you every success in your lager brewing. Hope my rambling posts are of some use.

 

[SanPancho]

I was always under the impression that time was of the essence when chilling the wort. I would hate to think of all the horrible things that could go wrong when leaving the kettle in my fridge for a few hours.

at the risk of sounding flippant, you need to relax and have fun with it. read the posting on the forum about "confessions" and you'll be amazed how much people get away with and still make great beer. my favorite is a post about how the guy turned around and found his two dogs were lapping up wort from the kettle while it was being chilled. (contrary to popular notions, a dog's mouth is not cleaner than a human's.) beer turned out fine.

as for chilling speed, you're confusing/conflating a few different issues. what matters to you specifically is that we're talking about chilling the wort to lager temps (~50F) from the mid-70s where you said your immersion chiller basically leaves the wort.

by the time you've gotten to the mid 70s you've already-
stopped hop aroma losses (~160-170-180F)
stopped SMS conversion to DMS (~170ish if i recall)
gotten out of the infection danger zone for wort (80F and above)

so there is no reason to worry about doing the last bit of cooling (~75 to 50F) in 8 hours (overnight) vs 20-30 minutes, as you've already taken care of the major issues noted above.

just keep it covered and it'll be fine. and clear. i promise.

 

[SanPancho]

forgot- there was another "confession" post where a guy with a cold accidentally sneezed a giant nasty snot rocket right into his whirlpooling wort.

he waited till everything settled, scooped out what he could of it. beer turned out fine.

hilarious.

 

[MaddBaggins]

The ground water just might be too warm. It cools super super slowly once it hits about 80. I can't imagine how long it would take to get to 50. I live in northern PA, I'm surprised I'm having that issue.

My ground water is as high as 90˚ in the summer and 70˚ in the winter. I use a homemade immersion chiller, run ground water till I get to 100˚ then add ice and recirculate until pitching temp.
I'm about to make my first lager next week. I hope I can get down to 50˚, otherwise it will just have to go into the fridge and pitch later.

 

[Pancoastbrewing]

at the risk of sounding flippant, you need to relax and have fun with it. read the posting on the forum about "confessions" and you'll be amazed how much people get away with and still make great beer. my favorite is a post about how the guy turned around and found his two dogs were lapping up wort from the kettle while it was being chilled. (contrary to popular notions, a dog's mouth is not cleaner than a human's.) beer turned out fine.

as for chilling speed, you're confusing/conflating a few different issues. what matters to you specifically is that we're talking about chilling the wort to lager temps (~50F) from the mid-70s where you said your immersion chiller basically leaves the wort.

by the time you've gotten to the mid 70s you've already-
stopped hop aroma losses (~160-170-180F)
stopped SMS conversion to DMS (~170ish if i recall)
gotten out of the infection danger zone for wort (80F and above)

so there is no reason to worry about doing the last bit of cooling (~75 to 50F) in 8 hours (overnight) vs 20-30 minutes, as you've already taken care of the major issues noted above.

just keep it covered and it'll be fine. and clear. i promise.

You're absolutely right about that. I've certainly not been perfect in any of my brew sessions and the beer turns out well. I would, at some point, like to enter a HB contest so I'm trying to really perfect the process. That acetyl presence would almost certainly sink me in any competition. I also only make lagers and I'm fascinated by the whole process.