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Slow to finish Imperial Stout, Or is it?

I brewed an Imperial Stout several weeks ago. My first very high gravity beer. After overcoming the fear put into me by YouTube videos of blowoff and exploded buckets I decided to ferment the batch in halves. Fermentation was vigorous to say the least for the first several days. Then slowed quickly. A couple of days ago (2 weeks into fermentation) I decided to rack into a glass carboy, combining the 2 halves and give myself an opportunity to check the gravity.

Here is my question, Can I expect a beer with a high gravity to continue at an almost unperceivable pace over the next few months to finish out at my expected final gravity?

My original gravity was 1.111, gravity at the time of racking was 1.036. I am expecting it to finish at about 1.027.

Hoping to have a glass on the coldest of February days.

Thanks for the help.

You’re at 10% ABV and ~67% attenuation. Depends on your yeast. It may have hit it’s limit?? Cheers!!!

Not really. Once you move the beer off of the yeast, even if it wasn’t at FG, you can’t really expect any more fermentation.

After two weeks, though, it was probably finished. What was the recipe? How did you come up with your target FG?

Yeast is Wyeast Irish Ale 1084, Mfg. states attenuation should be 71-75 percent, I chose the middle ground to base FG on. They also say it is tolerant to 12 percent alcohol.

My recipe is,
2 row pale, 10 pounds
plain extra light dry, 5.5 pounds, end of boil
roasted barley, 1.5 pounds
chocolate, 12 oz
dark crystal, 8 oz
black, 4 oz

153 degree mash, 90 minute boil

Hop additions to hit .8 BU:GU ratio with few late additions for a light aroma.

I am happy with the taste, just wondering if the yeast will do its job.

A couple of things popped out when looking at the recipe. The 5.5 lbs. of extract and the 153F mash. Both can contribute to a higher FG. I’ve not used 1084 much but I don’t recall it being a real attenuator. Maybe someone with more experience with it can chime in. Wouldn’t hurt to check your thermometer to make sure it accurate too. A few degrees could make a difference. Cheers!!!

The problem with that approach is that you don’t know what kind of wort Wyeast used to determine attenuation, and Wyeast doesn’t know anything about your wort. You could probably produce a wort that would ferment to 55% ADF, or 90% ADF.

At this point, whether the beer is finished or not, you probably won’t get further attenuation. By transferring you removed most of the yeast, and in order to restart fermentation you’ll need to pitch more yeast (preferably a starter at high krausen).

If it tastes good, though, you may not want to bother, unless you’re planning on bottling and worried about exploding bottles. In that case you should probably do a forced ferment test to determine the attenuation limit of the wort.

Well, I found most of my problem. After taking my OG reading I broke my hydrometer. Went to NB and purchased 2 more (one just in case). I never dropped them in plain water to see what they read and took my gravity reading when I did the transfer. The gravity reading of BOTH hydrometers in plain water at 59 degrees is 1.006, calibrated at 60 degrees.

I think that covers most of my discrepancy. I can live with 1.003 difference. Was a bit concerned with the 1.009.

Between the error in the new hydrometer and any difference in the calibrated scales between my original one and the new ones I would call it close enough. Lessons learned.


Brad, I happen to have a 1.111 OG brew going too, brewed on 11/11. Mine is a weizenbock, I’m using WLP300 and here on day 4 I just threw in a fermenting starter of US05 to help carry the load. So far it has a wonderful aroma of banana and caramel. I’m hoping for something in the 1.025 range too. Only time will tell, but I aerated and used lots of yeast and will rouse the yeast although right now it is churning nicely on its own.

Have you looked at Fred Bonjour’s big beer page? Google that up if you haven’t seen it, good info on making these monsters. I’m not that fond of big beers but they’re fun to make.

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