Unexpected high FG.

[Mandan]

I brewed my 1st lager - a Marzen. OG 1.062. 50F 21 days in primary and a 2 day D- Rest. 1.5 L starter using Wyeast 2308. Everything looked great until I took a gravity - 1.020. Now what? Is there any way to fix this? Or shall I go ahead and lager?

 

[Hex23]

I brewed my 1st lager - a Marzen. OG 1.062. 50F 21 days in primary and a 2 day D- Rest. 1.5 L starter using Wyeast 2308. Everything looked great until I took a gravity - 1.020. Now what? Is there any way to fix this? Or shall I go ahead and lager?

66% apparent attenuation (1.062->1.020) is definitely fairly low for that yeast.

If you used just one pack of 2308 for your starter, that's a pretty small starter for a lager that big. Normally you'd be looking at a 3-4 liter starter for a 1.062 lager.

Not the direct cause of your gravity problem, but a d-rest that late might not have been very effective at cleaning up diacetyl. It appears that your yeast went dormant. OTOH, you may not even have a diacetyl problem. However 2308 does often produce plenty of diacetyl, and might be more prone to do so with an underpitch.

As for what to do now, well it depends. Have you tasted it? Do you like it? A 1.020 finish for a Marzen may not be too bad. Are you going to bottle, or keg? If kegging, obviously no need to worry about bottle bombs.

If you do want to try to lower the gravity, you can warm even further and try rousing the yeast with a swirl or very gentle stir, but this might not work. A more likely trick would be to re-pitch fresh yeast from a larger starter. At this point you probably could get away with a very clean non-lager strain and not change the flavor profile too much.

Also be sure you've calibrated your hydrometer first. It's not at all uncommon for a hydrometer to be off by a few (1-4) points. E.g. your beer might really be 1.016.

 

[doug293cz]

I brewed my 1st lager - a Marzen. OG 1.062. 50F 21 days in primary and a 2 day D- Rest. 1.5 L starter using Wyeast 2308. Everything looked great until I took a gravity - 1.020. Now what? Is there any way to fix this? Or shall I go ahead and lager?

What was your predicted FG? AG or extract?

Brew on

 

[Mandan]

66% apparent attenuation (1.062->1.020) is definitely fairly low for that yeast.

If you used just one pack of 2308 for your starter, that's a pretty small starter for a lager that big. Normally you'd be looking at a 3-4 liter starter for a 1.062 lager.

Not the direct cause of your gravity problem, but a d-rest that late might not have been very effective at cleaning up diacetyl. It appears that your yeast went dormant. OTOH, you may not even have a diacetyl problem. However 2308 does often produce plenty of diacetyl, and might be more prone to do so with an underpitch.

As for what to do now, well it depends. Have you tasted it? Do you like it? A 1.020 finish for a Marzen may not be too bad. Are you going to bottle, or keg? If kegging, obviously no need to worry about bottle bombs.

If you do want to try to lower the gravity, you can warm even further and try rousing the yeast with a swirl or very gentle stir, but this might not work. A more likely trick would be to re-pitch fresh yeast from a larger starter. At this point you probably could get away with a very clean non-lager strain and not change the flavor profile too much.

Also be sure you've calibrated your hydrometer first. It's not at all uncommon for a hydrometer to be off by a few (1-4) points. E.g. your beer might really be 1.016.

Hey Hex, thanks. Good info here. To answer some of your questions, first it was all grain 10 gallon batch split with a brewing pal. I made two starters, one for each carboy. After the fact, I read that pilsners needed large cell counts. Too late now. The fermentation was roiling away though.

Why might I not need the D-rest? Because of the long 3-week+ fermentation?

We both got high FG- the other was 1.019. I'm going to keg, it tastes great, looks clear in the fermenter. I'll think about repitching, but will probably just keg and lager. Don't want to risk making things worse.

One other thing I find after reading my brew day notes - it was also my first two step mash. When we stepped up to 152F from 122F it settled at 158F. Cool water was quickly added, but perhaps some damage was done.

(edit) One other thing. The intended FG was 1.014.

 

[Mandan]

What was your predicted FG? AG or extract?

Brew on

Predicted 1.014. AG. The previous reply pretty much sums it up. I'm thinking it is a combination of several brew day mistakes. I'm getting ready to make my second lager this weekend and am making my starters at least twice as big. Plus I need to mind the mash temp.

 

[Hex23]

Why might I not need the D-rest? Because of the long 3-week+ fermentation?

I've found that even though some yeast are known for producing diacetyl, if they are treated well I never taste the diacetyl. I normally taste first before bothering with a d-rest. That said, both times I've used 2308, I had diacetyl.

Don't want to risk making things worse.

Probably the best decision. I had an o-fest land at 1.019 once (don't remember why), and it was still excellent.

One other thing I find after reading my brew day notes - it was also my first two step mash. When we stepped up to 152F from 122F it settled at 158F. Cool water was quickly added, but perhaps some damage was done.

Yep. Sounds like the high mash temp and underpitch are the culprits. Next time you make a starter for a large lager, also beware of the time it will likely take. You'll need to decant such a large starter and lager yeasts aren't typically very flocculent.