Yet another high final gravity

[dipole]

I searched many a thread and still can't figure out what to do. I brewed an imperial stout on 9/22, so about 3 weeks ago. It's still in primary. My gravity going into the fermenter was 1.104 using a 2L starter of London ESB yeast that never seemed to take off. I added another smack pack after a couple days and let it sit for the past 3 weeks. Just checked gravity and I'm sitting at 1.062. Final should be around 1.032
Ugh, what to do, is it too late?

 

[Rambleon]

That's a pretty low attenuating yeast but you should still have gotten more out of it. Tried swirling the carboy and raising the temp?

 

[sikkingj]

I agree about temperature; what temperature did you have your fermentation at? If the temperature got to low that could have put the yeast to sleep - especially in the 1.1+ environment. 1968 yeast can handle 70 degrees and that might be just what is need. Warm it up and shake the heck out of it.

Let us know what happens.

 

[dipole]

The first week I kept it at around 68 and then the past two weeks RT, which was around 72.

 

[reverendj1]

Did you aerate your wort?

 

[dipole]

could I add more yeast at this point or is it too late?

 

[dipole]

I didn't aerate it like I should have. I have an O2 tank that malfunctioned that day and I had to just give it a shake, so that's probably the root cause of the issue.

 

[progmac]

i don't think under aeration/oxygenation explains 40% attenuation.

what was your mash temp? any possibility something is wrong with your hydrometer?

 

[phuff7129]

I'm thinking there are several issues here. First London ESB is not a great high gravity/alcohol yeast. Second, a brew this big would require 366 billion yeast cells. Depending on how you prepared your starter and the date on your yeast packets you may have seriously under pitched. Combine the above with lack of oxygen and that could certainly cause it to stall out.

You will most likely need a more alcohol tolerant and highly attenuating yeast to finish this thing off. You will also need some yeast nutrient. I believe it is too late to oxygenate.

 

[mkeckjr]

I see threads like this (multiple batches with WAY too high of an FG) where often times the root cause is that one is using a refractometer to measure final gravity as opposed to a hydrometer, which will not give an accurate measurement. Is this possibly the case? Either that a malfunctioning hydrometer, as progmac pointed out.

Further, as Phuff said, this particular yeast you're using is a low attenuation strain. But since you mentioned in the title that multiple batches are finishing with too high an FG, I'm wondering if it's the refractometer or faulty hydrometer issue.

 

[progmac]

I see threads like this (multiple batches with WAY too high of an FG) where often times the root cause is that one is using a refractometer to measure final gravity as opposed to a hydrometer, which will not give an accurate measurement. Is this possibly the case? Either that a malfunctioning hydrometer, as progmac pointed out.

Further, as Phuff said, this particular yeast you're using is a low attenuation strain. But since you mentioned in the title that multiple batches are finishing with too high an FG, I'm wondering if it's the refractometer or faulty hydrometer issue.

or a faulty thermometer has you overshooting your mash temps

 

[2bluewagons]

This beer certainly falls into the category of "big" at 1.104 OG. To properly ferment a beer this big, different tactics come into play such as pitching plenty of yeast, mashing low (149-150), oxygenation (multiple times for a slow start to fermentation), and inclusion of simple sugar in your recipe. Sorry to be blunt, but sounds like you didn't do any of these correctly. So I don't think it is one thing, rather multiple factors that have put this beer where it is.

I love this yeast (WY1968) and made a darn tasty 10% beer with it, but that one was mashed at 151 and included 15% brown sugar. Alcohol tolerance is not the problem, you just needed to give the yeast a bit more to work with.

You could try to get a big starter of Cal Ale going and pitch at full Krausen and see where that gets you. Or if you are up for it, rebrew this one and do all of those things I mentioned above, but using the same yeast strain. I bet you will get lower than your expected 1.032 FG and then you could blend with this one and have a whole bunch of strong beer!

 

[dipole]

Thanks all for the diagnosis. I've never made a beer this big before and it seems I messed up at multiple points. The brew itself was fine, hit all my temps and my hydrometer is working fine, verified it with a couple buddies, it seems my yeast starter, choice of yeast and lack of oxygen stalled me out. Lessons learned for next time. I guess I'll just leave it be and drink it as is. It's still got 5.5% abv so it's not a total loss.