Lager fermenting faster than expected

[Tom R]

I'm making my first lager, and the fermentation is way ahead of where I thought it should be.
This is day six, and my 1.050 Vienna lager has gone from 1.050 OG to 1.013 as of last night.

I pitched a 4.5 liter starter of 2124 Bohemian Lager yeast, and have held it at 54F.

I was expecting to bump it up to 62F for a diacetyl rest after 2 weeks, but I'm concerned that I may be at final gravity before then. Does it matter? Maybe just RDWHAHB?

 

[str1p3s]

4.5 L seems huge for 1.050. I would bump it up for a few days rather than 2 weeks and then crash it for up to a few weeks. But definitely RDWHAHB.

 

[str1p3s]

Sorry, I read that you were going to do a d-rest FOR two weeks not after two weeks. With that much yeast going that fast you probably don't even need a d-rest but it won't hurt and I would do it now since you are close to your FG.

 

[Tom R]

Forgot to mention it is a 10G batch, hence big starter.

 

[mongoose33]

I've used that yeast and I've reached 50 percent attenuation after a bit more than 48 hours, so I'd say yours is fine. Plus, I start my lagers at 50 degrees, you're 4 degrees higher so it'd be faster.

I'd bump it up now for the rest. I'd go up 4 degrees every 6 hours until you get to 66 degrees. But that's me.

 

[HiImBrian]

I had just about the same thing with my WLP830 German lager yeast. 4L starter for a 10gal batch and I first checked it at about 1 week and it was at 1.010, so I slowly bumped up from 55 to 62 and will let it have for 2-3 days then slowwwwwly crash.

You're totally good!

 

[Tom R]

OK, good to know. I'm bringing it up to 64 over the next 24 hrs.

After the D-rest, does ramping down at 5F per day sound about right?

 

[mongoose33]

OK, good to know. I'm bringing it up to 64 over the next 24 hrs.

After the D-rest, does ramping down at 5F per day sound about right?

I'm sure it's fine. I do an accelerated lager ferm schedule; once up to the D-rest territory, I let it sit for 48 hours there, then down 6 degrees every 12 hours.

 

[Tom R]

I like the idea of an accelerated lager fermentation.
I was resigned to about 6 weeks, which hurts since I only have about 3 gals of homebrew left in the keezer!

How quickly can you turn around a lager? And how do you do it?
I've already seen how much time can be saved by the choice of yeast...

 

[mongoose33]

I like the idea of an accelerated lager fermentation.
I was resigned to about 6 weeks, which hurts since I only have about 3 gals of homebrew left in the keezer!

How quickly can you turn around a lager? And how do you do it?
I've already seen how much time can be saved by the choice of yeast...

This is largely borrowed from the approach Brulosophy advocated, so give them credit.

For whatever reason, I ferment lagers at 50 degrees. Works, haven't been motivated to try other temps.

The trick is to start ramping the temp up when the fermentation is about halfway done. That is, if your OG is 1.050, and your FG is presumed to be 1.010, then at 1.030 you'd start ramping up the temp.

Once there, start bumping up the temp 4 degrees every 12 hours, until you get to 66. By that time fermentation should be just about complete, unless you have a very slow attenuating yeast. (I've done this with both 830 and 2124 yeasts, worked fine for me with them).

Once at 66 hold it there for 2 days. Then start dropping down 6 degrees every 12 hours until you hit a temp at which you'd like to do some lagering. I usually stop about 38 or so.

At that point, I've been fermenting for....about a week or 8 days. I probably will hold it there for 10-14 days, depending on when I can rack to a keg for the remaining lagering.

I brew a dark lager using this approach that is more than drinkable at 2 weeks. I've brewed other lagers (a pils recipe, and a couple other general lagers) that are drinkable at 3 weeks, and still smoothing out.

The point of moving to the kegs by 14 days is to clear the fermenter for more.

 

[mongoose33]

I do starters a bit different with lagers than a lot of people do.

First, I only do 1-liter starters. I oxygenate the wort of the starter and add a bit of yeast nutrient.

Second, I try to time them so that I begin the starter 16-18 hours before I pitch it into my fermenter.

Third, my starters typically are at about 68 degrees, maybe 70 degrees. I try to get the wort in my fermenter to the same temp.

Naturally, I'll aerate the wort in the fermenter with oxygen.

Then, I'll hold that temp at 70 degrees or so after pitch for 6 hours before I begin to ramp it down to 50 degrees. My approach is predicated on having the starter be as active as it can be when I pitch it--no crashing, no decanting, the whole thing goes right in. Then, by leaving the temp at 70, I'm trying to get the starter to get me another doubling, or as close to it as possible, which simulates having pitched a double-size starter.

My approach seems to work. No apparent off flavors--and I've had others taste it and look for them. I'm sure it contributes to the speed at which the accelerated lager fermentation proceeds.

 

[Tom R]

Is your 1 liter starter for a 5G batch?

I'm making 10G, and the yeast was over two months old, so I needed 2 pkgs of yeast, with a 1.035 DME starter on a stir plate to get the recommended cell count. 18hrs for the pkgs to swell, and another 18hrs on the stir plate.

 

[mongoose33]

Is your 1 liter starter for a 5G batch?

I'm making 10G, and the yeast was over two months old, so I needed 2 pkgs of yeast, with a 1.035 DME starter on a stir plate to get the recommended cell count. 18hrs for the pkgs to swell, and another 18hrs on the stir plate.

Yeah, so if it is a 10-gallon batch, 2 liter starter.