lager - temperature change question

[02fx4dude]

My first lager is currently fermenting, planning to do a diacetyl rest at 69F, then rack to secondary and lager at 35F.

When bringing temperatures up for diacetyl rest and dropping down to lagering temperatures, is there a preferred rate at which to change the temperatures? IOW, is it possible to change the temperatures too fast and stress the yeast.

Thanks

 

[Yooper]

No, you can change the temperature quickly. First, yeast love getting warmer, so that's not an issue going up to a diacetyl rest. Plus, it takes a long time for 5 gallons of beer to change temperature anyway.

Dropping the temperature to lagering temps can be quick, as the yeast is done working anyway by then, although there is a theory that they can still work if you drop the temperature slowly. Since I rack after the diacetyl rest before lagering, that's not my thought.

 

[theveganbrewer]

I do it slow enough that I don't overshoot and freeze it by accident.

 

[02fx4dude]

Cool, thanks for the help. I don't know how fast I can bring the temperatures up and down, but I just wanted to make sure I wasn't going to ruin the beer.

 

[cheddared]

Also doing my first lager and had serious blow off. Wondering if I should put into another carboy to after I let it rest

 

[Yooper]

Also doing my first lager and had serious blow off. Wondering if I should put into another carboy to after I let it rest

In my opinion, a lager should always be racked after the diacetyl rest, as a lager is very "clean" tasting and without yeast character. Eight weeks is just too long on the yeast cake and can cause some yeast flavors as a result.

 

[Hex23]

My first lager is currently fermenting, planning to do a diacetyl rest at 69F, then rack to secondary and lager at 35F.

When bringing temperatures up for diacetyl rest and dropping down to lagering temperatures, is there a preferred rate at which to change the temperatures? IOW, is it possible to change the temperatures too fast and stress the yeast.

Thanks

That could depend on how you intend to package it. If you're going to keg, then definitely don't waste any time slowly dropping the temps. IIRC, slowly dropping temps is part of a certain German fermentation schedule that has the yeast actively working down to lower temps (See Kai Troester's website on lagering). It's not something that is recommended for home brewing.

However, there could be another reason to slowly drop temps. If you intend to carbonate by bottle priming, then you might want to consider slowly dropping temps so that you don't shock the yeast. Before I had kegging equipment, I did this and I never had to re-add yeast at bottling time, even after 2+ months of lagering.

 

[02fx4dude]

Good information Hex23. I keg and force carb, but that's good to know. Thanks. I'll check out that website you mentioned as well, can always use more brew knowledge.

I checked the gravity this afternoon and it's about 1.020, so I'm going to start bringing the temp up to 69F over about 12-15 hrs. I tasted the sample, wasn't quite sure what to look for to sense diacetyl, I didn't notice any kind of oily feeling or taste. Just to be safe I'm going to bring it up to 69 for three days and check gravity again.

 

[Yooper]

Good information Hex23. I keg and force carb, but that's good to know. Thanks. I'll check out that website you mentioned as well, can always use more brew knowledge.

I checked the gravity this afternoon and it's about 1.020, so I'm going to start bringing the temp up to 69F over about 12-15 hrs. I tasted the sample, wasn't quite sure what to look for to sense diacetyl, I didn't notice any kind of oily feeling or taste. Just to be safe I'm going to bring it up to 69 for three days and check gravity again.

Sounds good! Wait until it's done, and then rack and lager. Lagering in the keg is fine, and is great because you can purge with co2 and avoid oxidation completely.

 

[Hex23]

I'll check out that website you mentioned as well, can always use more brew knowledge.

Definitely worth reading: http://braukaiser.com/wiki/index.php?title=Fermenting_Lagers

 

[02fx4dude]

Sounds good! Wait until it's done, and then rack and lager. Lagering in the keg is fine, and is great because you can purge with co2 and avoid oxidation completely.

Lagering in the keg, that's a really interesting idea. It sounds good but I have one concern. I normally shake my kegs to carb, if I shake the keg after lagering will it stir up sediment I don't want to stir up after 5-6weeks? Or, can I do the last week or two of lagering at my carbing pressure, about 10-11PSI?

 

[shadows69]

Nice find Hex! That link should be a sticky. That may stop some of the same questions being asked over and over about the lager process.

 

[Hex23]

Lagering in the keg, that's a really interesting idea. It sounds good but I have one concern. I normally shake my kegs to carb, if I shake the keg after lagering will it stir up sediment I don't want to stir up after 5-6weeks? Or, can I do the last week or two of lagering at my carbing pressure, about 10-11PSI?

If you lager in the keg, you wont need to shake. Put the gas on right after you rack, purge a few times and set at normal carb pressure. By the time it's had enough lagering it will definitely be carbed.

 

[02fx4dude]

If you lager in the keg, you wont need to shake. Put the gas on right after you rack, purge a few times and set at normal carb pressure. By the time it's had enough lagering it will definitely be carbed.

OK, that's what I was wondering, if it would lager properly under pressure. I seem to remember some debates in the past whether ales will properly age under higher than 5-7 PSI. Thanks for the help, again.

 

[Hex23]

OK, that's what I was wondering, if it would lager properly under pressure. I seem to remember some debates in the past whether ales will properly age under higher than 5-7 PSI. Thanks for the help, again.

Forget where I picked up the idea to do this, but I don't remember hearing of any impact on aging. If you're concerned about stirring up sediment then another thing you can do is crash cool at the end of primary before racking and be careful not to pick up too much yeast in the transfer.