FG of 1.040?

[Potamus]

I brewed a Scottish wee heavy on Nov. 16. Target OG was 1.120 and I measured SG as 1.109. It's an extract brew, so that might be due to mixing. I racked to secondary on Dec. 13 and went to bottle it today, seven weeks after brewing. I'm concerned because the target FG was 1.030, but I measured 1.040.

The beer has been stagnant for weeks, with no airlock activity and no bubbles or yeast movement in the beer itself. Ambient has been a constant 64 degrees. I know it's common to have attenuation issues with beers this big, and I'm wondering if a yeast substitution I made could explain it (recipe called for Wyeast 1728 Scottish ale yeast; I used US-05). By my calculations, I got only 63 or 66 percent attenuation, depending on which OG was accurate.

I went ahead and bottled it, thinking the yeast may have simply reached its limit (beer is between 9-10.5 percent ABV). Now I'm worried it may have actually been a stuck fermentation and that I should be concerned about bottle bombs.

Does it sound like this is going to give me exploding bottles or flat, sweet beer? The sample was pretty tasty, BTW.

Here's the recipe:

9 pounds golden light DME
6 pounds extra light DME
16 ounces 60-degree Lovibond crystal malt
4 ounces chocolate malt
4 ounces peat-smoked malt
2.5 ounces black malt
1 ounce Northern Brewer hops
2 sachets US-05

 

[gilstein21]

i'm not exactly sure but they may be too big of a beer for US-05.

 

[TungstenBeer]

i'm not exactly sure but they may be too big of a beer for US-05.

Could be a us-05 issue, yeah. I believe alcohol tolerance is 12%... Right now you are around 9% so I don't think that's an issue.

What have your temperatures been in the fermenter?

That being said, it's not uncommon for extract brews to fail to fully attenuate, as you said. Although I generally have had more luck with DME.

 

[cluckk]

I know it's common to have attenuation issues with beers this big, and I'm wondering if a yeast substitution I made could explain it (recipe called for Wyeast 1728 Scottish ale yeast; I used US-05).

I'm pretty sure this was the reason. 1728 is very high gravity tolerant. I doubt US-05 will handle that high of gravity. Besides you also add crystal which will add some unfermentables.

 

[Trox]

First I would let that bulk age in a secondary for at least 3-4 months before bottling.

Second how did you aerate your wort prior to pitching? I brewed a Wee Heavy that is sitting in secondary where i had the exact same problem (used Edinburgh yeast), stopped at around 1.040 when it should have been 1.030 also (OG of 1.110). A big beer like that really needs to be infused with O2 and shaking or an air pump just will not cut it.

Edit: SA-05 can handle up to 12% so I would have expected you to get closer. How big of a starter did you make btw?

 

[stevedasleeve]

I would be worried about bombs, keep em cold and watch out is my advice!

 

[JonM]

You could always brew a Scottish 70/- with 1728 and, when it's done, put the wee heavy on its cake. That trick has worked like a charm for me every time I've had a stuck ferment.

 

[Potamus]

Thanks everyone for the quick replies. TungstenBeer, the temps in the fermentor hit about 67 degrees during active fermentation and have been about 63-64 since. Trox, I plan to let it age for several months in the bottle. I don't have the ability to infuse pure oxygen, so I basically did the best I could by letting the wort splash in and then shaking it. I didn't make a starter, just pitched two packets of re-hydrated yeast. I used a calculator and it said that should have been enough.

 

[mmb]

Getting temp up a bit to the low to mid 70s and see if that wakes it up a bit. Toward the end of fermentation the temps really don't matter as much as the early fermentation when the yeast is ripping along.

 

[Trox]

As a heads up a beer that big will need at least a year aging time for it to start to shine. I believe your issue was the same as mine; not enough O2 in the wort for the yeast to really do their job so the 1.040 is probably the best they'll be able to do. And yeah forgot you used dry yeast when I asked about the starter (was thinking of mine where I needed about 4L of starter to get enough cells), but 2 packages should have been plenty.

 

[Cyclman]

An O2 injector, IMO, is a great investment after temp. control. I make lots of big beers, and get great attenuation, I believe O2 injection is part of this.

 

[jjkeegan86]

Any updates on this, I'm in the same boat worried about bombs, what did you do and what happened?

Thanks

 

[Potamus]

I just put the bottles in a box for a while to contain any potential bombs. But that hasn't been a problem, in fact just the opposite. They've been pretty warm over the summer, but when I tried one about a week ago the carbonation was still way too light. There were some bubbles coming out of solution, but no head. I think the yeast basically hit its limit on the ABV. The beer still tastes good and I don't think there's much danger of bombs anymore, but it's too sweet and lacking carbonation. Next time I'll stick with the recommended yeast and try to aerate better.