Fermentation stuck at 1.030

[Pixalated]

I tried brewing an imperial stout, which came out to 1.072 OG. After a month in the basement, my SG was 1.030. I think that was due to the temperature. So, I racked to secondary and moved it to a warmer room two weeks ago. The gravity is still 1.030, but it tastes pretty good. Is it dangerous to bottle with gravity that high? I really don't want bottle bombs.

Should I add more yeast to it to try and bring down the gravity?

In case it matters, I didn't make a starter but used two yeast vials instead.

 

[Bierliebhaber]

What was the recipe? Temp of fermentation? Yeast Strain? If all-grain, what temp was the mash? Did you aerate? Need a few more specifics to help.

Your SG does seem rather high, especially for your OG.

For future reference, it would have been preferable to just move the primary to a warmer location and rouse the yeast, by swirling, a couple times a day for a week to see if that worked.

 

[Pixalated]

I didn't think providing too many details would be necessary, sorry.
I used the yeti clone recipe from here Brew Your Own: The How-To Homebrew Beer Magazine - View by Issue - December 2006 - Tasting Double and made it with extract.

I did aerate by shaking the carboy for a few minutes. The stick on thermometer read about 65 on the second day, but after a week it dropped to the hight 50s.

 

[Bierliebhaber]

I'm glad I asked for the recipe! I love Yeti.

Yes, that drop in temp would definitely make the yeast inclined to sleep.
If you can get your hands on some yeast energizer and warm the fermenter up to 70F, that may do it. If you add more yeast, you should make a small starter to get the yeast hopping. Pitch about 12hrs after beginning the starter.

To answer your question about bottling, I would be very reluctant to bottle this without getting that SG down.

 

[Pixalated]

So, you are suggesting two different things?
1. Either add yeast energizer and warm up the fermenter
or
2. Make a starter and add it to the fermneter

Yeah, I heard about bottle bombs, and have no desire to experience them.

 

[Yooper]

That recipe says an OG of 1.090. Did you not get that? You'd get 1.065 from just the extract alone.

 

[Bierliebhaber]

I would try #1 first because that will save you $10, but I'm not sure how much yeast you still have. Either way, you want to have it at room temp.

 

[Calder]

I tried brewing an imperial stout, which came out to 1.072 OG. After a month in the basement, my SG was 1.030. I think that was due to the temperature. So, I racked to secondary and moved it to a warmer room two weeks ago. The gravity is still 1.030, but it tastes pretty good.

If, as you note, the reason the beer stopped at 1.030 is because of temperature, then you left your yeast in the primary bucket when you racked.

When yeast go dormant, they also drop out of suspension (that's what happens when folks cold crash). If that is what happened, when you racked to secondary, you left most of the yeast behind, and only have a few million left. What you have left should be good for bottle conditioning, but not able to convert a lot of sugars quickly.

If you think cold was the problem, you would be best off making a starter with a new yeast and pitch when actively fermenting. Just sprinkling a yeast packet in there now is not going to move it very quickly.

 

[Pixalated]

@Yooper, I had the grains in the bag and I probably got very poor efficiency. I've never mashed before.

I will try adding making a starter.

 

[Yooper]

@Yooper, I had the grains in the bag and I probably got very poor efficiency. I've never mashed before.

I will try adding making a starter.

The reason I ask is because if you're wrong about the OG (which could be possible if you topped up with water), and you were actually closer to the projected OG of 1.090, you're already at 8% ABV and unlikely to do any better with pitching fresh yeast.

If your OG really WAS 1.072, then yes I'd say you're stuck. That's what I'm trying to figure out. Stuck vs. finished.

 

[Pixalated]

I took the gravity after topping off, but now you are really making me doubt myself.

 

[Yooper]

I took the gravity after topping off, but now you are really making me doubt myself.

Sorry! But, unless you stirred and shook, then stirred and stirred some more, it's very likely that the heaviest wort sunk to the bottom while the lighter wort diluted more with water "floated" on the top. That happens all the time, and so when I've had to top off, I've made sure that the wort is equal throughout and tried to take a sample from near the bottom and one from near the top, to make sure they were the same. And often, they weren't. So I stirred some more.

It's possible that you got terrible efficiency with the partial mash, but it's probably more likely that you got a poor OG reading at the beginning.

It really doesn't matter, except that now it's unclear whether you're stuck, or finished. I guess pitching more yeast can't hurt, and if it still doesn't budge in a week, then consider it finished.

A couple of lessons for next time- don't rack until you're at FG, and stir the wort better before taking an OG. But for now, the beer tastes good and that is really the important thing anyway!

 

[Pixalated]

Thank you for the lesson. I will need to get a longer beer thief. And hopefully, I'll be going all grain for my next batch.

 

[Pixalated]

Felt like bumping this thread would be better than starting a new one. So, I made a 1.3L starter, put it on the stirplate for 24 hours and then pitched. I also got a space heater for my fermentation room and dialed in the temperature to 70F. Well, after 12 days my gravity only dropped by 3 points. I like the way it tastes, and I am OK with bottling it as is.

My only concern are bottle bombs. Is it safe to bottle?