high fg?

[rweird]

brewed up a ris the other month. og was 1.084. pitched a 1L starter of WLP028. after probably 4weeks in primary at ~68 degrees fg was sitting at 1.031. expected is 1.021. I "shook" the primary to rouse the yeast and raised the temp to ~74 let it sit for another week. fg didn't drop. made another 1L starter and pitched it last week. assuming it hasn't dropped again what are my options to get the fg down further? recipe was

.5lb roasted barley
.5lb black patent
.5lb chocolate
9lb dark extract
2oz warrior for 60 min
2oz cascade for 0 min

 

[SubmergedBrewing]

Well, as it stands right now and doing my math correctly, you have about 63% attenuation in your beer right now. overall goal is 75% but looking at your grain bill, there is not a lot of fermentable sugars overall in your recipe, which will drive your attenuation down. additionally, your yeast has a lower attenuation level than others and it will take a lot of effort to ferment those sugars in your batch.

One option you have is to repitch another vile of WLP028 or when it comes time to repeat this recipe, swap some dark for some light.

Also, I put your bill through my software and i got an FG of about 1.023 so i would say you're good

 

[wonderbread23]

With 9lbs of dark extract, that's probably all you're gonna get.

 

[ajf]

I wouldn't pay too much attention to FG figures predicted by Beersmith or similar programs, or even to the attenuation figures published by White Labs.
I brew a lot of Bitters with WLP002, and White Labs say that the attenuation for that yeast is 63 - 70%, but I regularly achieve 80 - 85% attenuation. The last beer I produced (that has finished fermenting) had an FG of 1.008 (83% attenuation), while Beersmith predicted an FG of 1.016.
As the other posters said, using dark extract will result in a higher FG. If you want to reduce it, I would switch to a lighter extract and adjust the color (if necessary) with a bit more specialty malt.
Another possibility for the high FG is the brand of extract that you are using. Some are more fermentable than others, and according to Ray Daniels (Designing Great Beers) DME is usually a bit more fermentable than LME.

-a.

 

[rweird]

ok was thinking that might be part of the issue. now it really isnt much of an imperial stout at <7% and it's obviously alittle sweet. how much corn sugar do you think I should add to bump up the abv and thin/dry it out alittle?

 

[ajf]

Adding sugar will thin it out a bit, but if fermentation really has finished, the high FG is caused by the unfermentables, and adding sugar won't get rid of them, although it should it won't drop the FG much. Each pound of corn sugar, added to a 5g batch will increase the ABV by about 1.1%, and I wouldn't go over 1 lb (which would be about 12.5% of your fermentables). In fact, I wouldn't add any, and put up with a sweeter and lower alcohol beer than intended.

-a.

 

[rweird]

i realize that adding sugar wont get rid of unfermentables but why put up with something when i can add more fermentables to dry it out slightly? its a big beer should i really worry about off flavors with 1lb of corn sugar?

 

[rweird]

anyone?

 

[rweird]

well checked the gravity again and it hasn't moved. 1.031 decided I wanted it to be drier and thinner so I ended up adding 1lb of corn sugar. guess we'll see how it is in a few days. I really want to get this bottled.

 

[jfr1111]

What ajf was trying to tell you is that adding sugar will only bump your gravity, it won't make your fg any lower wich is the reason you ended up on the sweet side. The sugar won't dry out your beer, only a lower fg will do that, but it will probably thin the mouthfeel quite a bit and increase the alcohol if the yeast are up to the task of fermenting it.

The first thing I learned by reading on here is that amber and dark malt extracts are unecessary 99% of the time. You don't know what's in there and it really messes with the expected attenuation figures because they contain a lot of unfermentables.

 

[rweird]

got it. thanks. in the end it will still be beer. it has around 80ibu depending on which software I plug it into so the extra sweetness shouldn't kill it. maybe it will get bottled this weekend.

 

[rweird]

just an update, after adding the 1lb of dextrose fermentation started again. went good for probably a week. just checked the fg and its at 1.026.:rockin: looks like the yeasties just needed some simple sugars to get them going full tilt again. I never took a sg but software says it should be about 1.092 when all was said and done. so 1.092->1.026= 8.7%abv. thats much better