Lagering process specifics

[Gosling]

I am led to understand that the flavour profile of a lager changes during the lagering phase and in some cases slight "off" or "green" flavours can be corrected over time during this phase.

Can someone tell me which undesirable flavours have a chance of lagering out and which that will never ? (phenol, acetaldehyde right ?)

Reason I ask specifically is I have a lager now that has a very very slight phenol hint. I just know it is there. Wondering whether to bin it because it bothers me or give it a chance...but 4 weeks is a long time ...

 

[slcmorro]

Lagering can be done for longer than 4 weeks. It's your choice entirely if you want to bin it, but personally I wouldn't. If it was terrible to the point of annoying you, why not blend it with something else? Diacetyl can't be corrected as far as I understand, but as the beer clears up and ages more, other flavours can become muted or more pronounced. Unless it's taking up space, I'd leave it and taste it periodically.

 

[manticle]

Diacetyl can be corrected, depending on the cause. If not bacterial in origin, all it needs is contact with healthy yeast. Proper lagering will reduce diacetyl. If you have a diacetyl problem after doing a d-rest with a lager, you can krausen the beer to reduce it.
Best to avoid getting high amounts in the first place but it can be fixed.

 

[mje1980]

Manticles last line says it all. Do all you can to avoid undesirable flavours rather than trying to fix them. A "D" rest isn't necessary if the yeast doesn't produce any. Pitching lots of yeast cold ( slightly under ferm temp, then letting raise up to ferm temp ) helps to keep it crisp and clean.

 

[Eagleburger]

phenols are there for good I believe. I had to tip a brew due to phenol. Wsa due to chlorine in water supply.

 

[Goose]

Diacetyl can be corrected, depending on the cause. If not bacterial in origin, all it needs is contact with healthy yeast. Proper lagering will reduce diacetyl. If you have a diacetyl problem after doing a d-rest with a lager, you can krausen the beer to reduce it.
Best to avoid getting high amounts in the first place but it can be fixed.

Have been having issues with delayed appearance of diacetyl following an apparently successful S189 fermentation despite a diacetyl rest, and was led to believe it could be a bacterial infection causing it.

Nonetheless I tried a correction, but not having any active krausen to pitch nor the inclination to make a starter I rehydrated a pack of S23 and pitched that into two kegs after 15 mins of hydration, and left them to stand for 2 days at 20 deg C. I was relieved to learn that this did in fact correct the problem and the result after a further 2 weeks of "lagering" was a damn good beer.

Prevention is always better than cure, but sometimes you need a cure and was very surprised to see that rehydrated yeast could do the job.

I put the delayed diacetyl formation down to stressed yeast in the original ferment. Dried yeast and lagers are just not cutting it for me somehow

 

[GalBrew]

There is nothing wrong with dried lager yeasts, so long as they are used properly. I use w-34/70 for all of my lagers and the beers that get sent off to comps never have any mention of fermentation flaws.

 

[Goose]

There is nothing wrong with dried lager yeasts, so long as they are used properly. I use w-34/70 for all of my lagers and the beers that get sent off to comps never have any mention of fermentation flaws.

can I ask how many pkts per 23 litres, do you sprinkle or rehydrate and at what temp do you rehydrate and pitch pls ?


thanks

 

[fraser_john]

I put the delayed diacetyl formation down to stressed yeast in the original ferment. Dried yeast and lagers are just not cutting it for me somehow

Nothing wrong with the dried yeast, must be something procedural you are doing(or failing to do) to stress the yeast. Should be an easy fix though, more oxygen, more yeast, rehydrate yeast (flame suit on), pitching temp, fermenting temp, nutrient levels etc etc etc.

 

[GalBrew]

can I ask how many pkts per 23 litres, do you sprinkle or rehydrate and at what temp do you rehydrate and pitch pls ?


thanks

I use 2 packets per 23l batch, rehaydrated in about 220ml of pre-boiled water. I no-chill so I have my cube of wort at 10degC for pitching, and I add 1.5L of oxygen into the wort at pitching. I then ferment at 12degC, but I do the 'Tasty McD' lager ferment where I ramp up the temp as the beer ferments. I then 'lager' the beer for as about a week or so at 1 deg C. Then I keg and force carb. I like to lager the beer in the keg for a least a couple of months (at 3-4degC) before drinking. My last one had 3 months lagering in the keg and placed 3rd at AABC recently.

 

[Goose]

I use 2 packets per 23l batch, rehaydrated in about 220ml of pre-boiled water. I no-chill so I have my cube of wort at 10degC for pitching, and I add 1.5L of oxygen into the wort at pitching. I then ferment at 12degC, but I do the 'Tasty McD' lager ferment where I ramp up the temp as the beer ferments. I then 'lager' the beer for as about a week or so at 1 deg C. Then I keg and force carb. I like to lager the beer in the keg for a least a couple of months (at 3-4degC) before drinking. My last one had 3 months lagering in the keg and placed 3rd at AABC recently.

great stuff tks, can I ask one more question if I may, at what temp do you rehydrate ? pitching temp or room temp ?

 

[GalBrew]

I add the yeast to the water at around 27degC and leave it at room temp on a stir plate for 20-30mins.

 

[pyrosx]

I rehydrated a pack of S23 and pitched that into two kegs after 15 mins of hydration, and left them to stand for 2 days at 20 deg C. I was relieved to learn that this did in fact correct the problem and the result after a further 2 weeks of "lagering" was a damn good beer.

Any reason you used one yeast originally, and then picked a different one for the "correction"?

I've got a keg of lager fermented with 34/70 with a noticeable diacetyl problem - it's a great beer, except for the aftertaste, which is putting me off wanting to drink it.

Contemplating attempting a similar correction, but wondering what yeast I should buy to do it with... the same yeast, or something different? I've got a packet of US-05 available, would using an ale yeast cause issues?

 

[manticle]

Most of the flavour profile will be set so what you need is simply active, healthy yeast.

That said, unless the original strain is hard to get or a known high diacetyl producer, I can't see why you wouldn't go for the same one again.

 

[Goose]

Any reason you used one yeast originally, and then picked a different one for the "correction"?

I've got a keg of lager fermented with 34/70 with a noticeable diacetyl problem - it's a great beer, except for the aftertaste, which is putting me off wanting to drink it.

Contemplating attempting a similar correction, but wondering what yeast I should buy to do it with... the same yeast, or something different? I've got a packet of US-05 available, would using an ale yeast cause issues?

Depends if you have the same one available, I didn't.

Having said that I agree with Mants. You just want something to clean up a few ppm of nasties that unfortunately we can taste. Though I cannot say for sure I doubt that the S23 added or changed the flavour profile, just cleaned it. I'd give the US-05 a go and would be keen to hear the results.

 

[alcoadam]

Major German breweries are bottling in under 3 weeks and use warmer ferment temps (14 or so degrees). Their beer comes out clean and hard to fault...

I've tried pitching very healthy levels of yeast to produce a similar result and whilst the beer is good, it does fall just short of what I was hoping for.

My thinking these days is, an oxygen bottle's required to really nail it?

 

[manticle]

I think that is key and the next addition to my setup. I also understand commercials will pitch a massive number of yeast cells - far beyond what is practical on hb level.
Filtering will also expedite matters.
As homebrewers we don't have the same pressure to get finished product available so I don't mind taking time when it has a perceptible benefit.

 

[pyrosx]

Thanks for the clarification Goose - I wasn't sure if you had something magical going on that I wasn't privy to....

I think I might end up going with the US-05, just because it's on hand and cheap.... and at this point, seems worth it purely for the experimental value.

Will report back with results.

 

[fraser_john]

Unless sterile filtering, even a super clear beer will still have active yeast floating about, if not under pressure to get it onto the tap, just wrap it in a heat belt and sit at 20c for a week or two, whatever lager yeast from the original ferment is still around will clean it up nicely, no need to pitch extra yeast.

My lager process involves fermenting to final gravity, say 1008 or 10010, then ALWAYS wrapping in a blanket, raising to 20c and resting for 2-3 days whilst still on the yeast cake, regardless of how the beer tastes after reaching final gravity. This allows the yeast to clean up anything left over, before it has a chance to metabolise into something that can be tasted. Then keg and lager at 2-3c.

As for pitching rate and ferm temps, my last three lagers have been fermented at 14c as well, with three packs of the Mangrove Jacks Bohemian Lager yeast and they have all been excellent fermenters, reasonably fast with a nice clean profile. Very happy with that particular yeast at the moment.

 

[mje1980]

I'm in the middle of brewing a mid strength lager at the moment. I'd normally use a big, stir plate starter of Danish Lager pitched cold. However, this time I don't have any but I do have 2xpacks of 34/70. I plan on pitching both cold ( 6c ) then raising to 10c. I thought about rehydrating but that needs to be done at warmer temps, and I don't like the idea of pitching nice rehydrated yeast at 25-30c into 6c wort, just seems a little odd, like it would shock the yeast. The lager is 1.031, so I figure that 2x34/70 should be plenty. Will update.

Lagers are not my fave, but a nice crisp lager in hot weather is a thing of beauty, and worth the occasional effort I reckon.

I tried starting cold then ramping up lager ferment but for me they were nowhere near as good as the pitch cold and keep cold for a longer time.