Why rack lager at 70% attenuation?

Why do we rack lagers at ~70% attenuation?

If I rack into my keg to lager there, wouldn't this mean I'd have more sediment? Should I wait until it's closer to completion and then rack? Any problem with keeping it in the primary for even longer and then eventually racking and reducing temps to lagering temperatures? I'm currently brewing at about 50F.

Jacktar said:

Why do we rack lagers at ~70% attenuation?

If I rack into my keg to lager there, wouldn't this mean I'd have more sediment? Should I wait until it's closer to completion and then rack? Any problem with keeping it in the primary for even longer and then eventually racking and reducing temps to lagering temperatures? I'm currently brewing at about 50F.

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I'm not much of a lager brewer but I've never heard that you should rack to kegs at 70% attenuation. Can you link to a reference?

If your gravity readings are stable then it's done. Rack and lager.

There are times that my beer will sit on the yeast cake for weeks after FG has been reached just becasue of not enough time in the day and they all come out great.

Where did you see to do this? Around 70-80% attenuation you should perform a diacetyl rest, but that is the only step around that timeframe I have seen.

Oops. I meant to say that people perform the diacetl rest. My question is whether or not that rest can wait until fermentation is essentially complete. Or, is that 30% needed to finish the process at higher temps?

I guess if I rack after the rest, there wouldn't be a lot of sediment.

I think you'll want the yeast active enough to do the d-rest.

So, in a 1050 beer, I do the d rest at 1020ish?

Rockn_M said:

I think you'll want the yeast active enough to do the d-rest.

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I am not a big lager brewer, but i would think that if you wait until the yeast are closer to finished fermenting to start the d-rest you would have a smaller number of active yeast to clean up.

By starting the d-rest while the yeast are still fairly active you are allowing a greater number to clean up after themselves.

I may be wrong, but that is how it makes sense in my head.

The usual process is to begin the D-rest (if you even need to do one) when the brew is about 75-80% of the way to FG. For most lagers, this will be around the area of 1.020. D-rest for a few days, then cold-crash and transfer for lagering.

You want to D-rest while the yeast are still active, hence why recommended around 80% completion. If you wait until the end of fermentation, the yeast is now flocculating and dormant, and you wont be cleaning up much of the byproduct.

LLBeanJ said:

The usual process is to begin the D-rest (if you even need to do one) when the brew is about 75-80% of the way to FG. .

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Since I'm not sure I know enough about diacetl to detect it, I'll probably do a d-rest. Just checked my gravity and it's at 1020. Time to up the temperate I guess.

Jacktar said:

So, in a 1050 beer, I do the d rest at 1020ish?

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I wouldn't even think that hard about it. Wait a week into fermentation then let it free rise to the mid 60's, hold for another week or so, then keg it. This is what I do and I brew mostly lagers these days.

beersk said:

I wouldn't even think that hard about it. Wait a week into fermentation then let it free rise to the mid 60's, hold for another week or so, then keg it. This is what I do and I brew mostly lagers these days.

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I try to keep it simple myself. I let the temp rise when I see the Krausen start to fall. I've never bothered to draw SG samples

Natdavis777 said:

I try to keep it simple myself. I let the temp rise when I see the Krausen start to fall. I've never bothered to draw SG samples

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This is what I do, as well.

Natdavis777 said:

I try to keep it simple myself. I let the temp rise when I see the Krausen start to fall. I've never bothered to draw SG samples

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Same here.

So how long do you guys d-rest for? And then how long do you lager before you start drinking it?

I d rest for 3-7 days on most lagers. Then I lager for a week per 2 degrees plato as a rule of thumb. That may be overkill.

Jacktar said:

So how long do you guys d-rest for? And then how long do you lager before you start drinking it?

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I do a diacetyl rest as long as needed, sometimes 24 hours if there is little to no diacetyl noted and the FG is reached, otherwise it's until FG is reached and fermentation has stopped, easily a few days.

Then I rack and lager for one week for every 8-10 points of OG. So, for a 1.050 OG lager, I'd hold it at 34 degrees (or just above freezing) for 5-6 weeks or so.

Yooper said:

I do a diacetyl rest as long as needed, sometimes 24 hours if there is little to no diacetyl noted and the FG is reached, otherwise it's until FG is reached and fermentation has stopped, easily a few days.

Then I rack and lager for one week for every 8-10 points of OG. So, for a 1.050 OG lager, I'd hold it at 34 degrees (or just above freezing) for 5-6 weeks or so.

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Do you rack into the serving keg (when kegging) or into an intermediate carboy / keg ?

black_belt said:

Do you rack into the serving keg (when kegging) or into an intermediate carboy / keg ?

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I generally rack into a keg now, and then 'jump' to the serving keg later. Before I was kegging, I racked my lagers into a 5 gallon carboy for lagering.