Effect of adding sugar after primary to Imperial Stout

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jah777

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Hello All,

I know that there are a zillion threads on the general subject of adding sugar to beer, but I'm hoping for some helpful feedback for my particular situation. I don't believe the misconception that adding table sugar results in a cidery beer, so please do not respond with this comment.

So, I brewed my first high gravity beer with all grain, a Russian Imperial Stout, and my efficiency was really poor (54% mash efficiency and 50% overall efficiency). Instead of a 1.107 SG, my SG was only 1.078. I mashed at higher temperatures for a full body, and now it appears that fermentation is fairly complete in primary with a FG of 1.028 and an abv of ~6.3%. It has only been in primary for about 5 days, but all the fermentation happened in the first 36 hrs and it is only bubbling 1-2 times/minute, so I don't expect much additional attenuation.

Since the abv is lower than desired and the FG is fairly high, I am considering adding about 2-3 lbs of table sugar with a pack of rehydrated yeast to increase abv by 2-3%. I know this will likely thin out the beer, but I assume with a gravity of 1.028 thinning is probably not a huge concern. I expect that the beer would be fine even if it thinned to a FG of 1.018 or so.

What do you think about adding 2-3 lbs of table sugar and a packet of rehydrated yeast following primary fermentation in this context?
 
2 to 3 pounds is excessive and I fear will result in a beer that doesn't taste as good as what you started with. Also with a bigger beer just because you see very little bubbles doesn't mean it's done fermenting. Just curious how high did you mash?
 
Fairly complete does not mean complete and the yeast may surprise you. I would give it more time as some yeast take awhile to manage those last points:)

I agree 2-3 lbs of sugar seem extreme but if you were to add it I would recommend it being dissolved and any added test should be in active fermentation because of the present alcohol, of you just toss it in it may just stress out and not perform.
 
It is still fermenting, put it in the corner and keep it warm, and I'm sure you will knock a few more points off.

3 lbs of table sugar added to a 1.078 will probably get you an effective OG of 1.105. That will be roughly 25% sugar. It is probably high, but wont bee too bad. That's probably twice what I might use.

Assuming you are stopped at 1.028 (I suspect you are not finished), and you add 3 lbs of sugar, you are correct that it will take you down to somewhere around 1.018.

You do not need to add any more yeast. In fact, it would be a waste of yeast.
 
add more dme or a blend of DME/simple sugar (maybe 2:1) if you want to bring the gravity up

with a RIS I'd rather have a slightly high FG than too low and thin feeling
 
add more dme or a blend of DME/simple sugar (maybe 2:1) if you want to bring the gravity up

with a RIS I'd rather have a slightly high FG than too low and thin feeling

This.
Made an oatmeal stout kit when first starting. I really stressed at the fact that it finished high. It is to this day one of the best beers I have made. You may want to try gently swirling your fermentor to help rouse the yeast . Don't shake to the point of adding air, just move it enough to give it a chance to kick up. I do this once every couple days when I ferment and have had my FGs improve dramatically. But I also let it go for three weeks. Five days isn't long enough for regular gravity beers, let alone one up around 1.070.
 
To make those high gravity, AG beers you usually end up with almost 10 gallons in the kettle and have to boil forever to get down to 5. My usually plan for those is a mostly AG to manage the volume into the kettle, then use light DME to get the gravity where it needs to be in the kettle.
 
Thank you, everyone, for your helpful replies! Regarding my mash temp, I mashed at 156 deg F for about 1.5 hrs and ended with a mash temp around 153 deg F. I was going for full body. I'm okay with a FG of 1.028, I'm just not too thrilled about an RIS with only a 6.5% abv! I understand that since it has only been fermenting about a week now that it could continue to attenuate (it has dropped down to 1.026 since my last reading 4 days ago), but even with further attenuation I don't expect to reach a % abv that would be high enough for my preferences.

As it stands now, based on the feedback, my plan will be to go by the brew store and get about 3 lbs of DME to add to primary sometime later this week. After 2 weeks in primary, I will plan to dissolve the DME in water, boil, cool, add to the carboy, and give the carboy a swirl to get the yeast suspended again. Since I expect the yeast to consume the sugars and produce CO2, I assume that swirling the carboys at this stage will not raise a concern about oxidation. Any thoughts?

I'm not thrilled about having to add DME to reach my target gravities, but I also have neither the time nor the brew pot to start at 10 gallons and boil down to 5 to concentrate the wort. I'm hoping to try this recipe again in the future and tinker with a few things to increase efficiency. Advice on this would be appreciated also. I am batch sparging with a 5 gallon cooler and an 8 gallon brew pot.
 
jah777 said:
Thank you, everyone, for your helpful replies! Regarding my mash temp, I mashed at 156 deg F for about 1.5 hrs and ended with a mash temp around 153 deg F. I was going for full body. I'm okay with a FG of 1.028, I'm just not too thrilled about an RIS with only a 6.5% abv! I understand that since it has only been fermenting about a week now that it could continue to attenuate (it has dropped down to 1.026 since my last reading 4 days ago), but even with further attenuation I don't expect to reach a % abv that would be high enough for my preferences.

As it stands now, based on the feedback, my plan will be to go by the brew store and get about 3 lbs of DME to add to primary sometime later this week. After 2 weeks in primary, I will plan to dissolve the DME in water, boil, cool, add to the carboy, and give the carboy a swirl to get the yeast suspended again. Since I expect the yeast to consume the sugars and produce CO2, I assume that swirling the carboys at this stage will not raise a concern about oxidation. Any thoughts?

I'm not thrilled about having to add DME to reach my target gravities, but I also have neither the time nor the brew pot to start at 10 gallons and boil down to 5 to concentrate the wort. I'm hoping to try this recipe again in the future and tinker with a few things to increase efficiency. Advice on this would be appreciated also. I am batch sparging with a 5 gallon cooler and an 8 gallon brew pot.

Sorry, this last post is causing me major confusion. You tried to mash a 1.10+ grain bill in a 5 gallon cooler? You don't want to boil down 10gallons of wort in a 8 gallon kettle? The math here is not adding up here which makes answering your questions even more difficult as to why things didn't turn out.

A 5 gallon MLT will get you a 1.060 beer and an 8 gallon kettle is barely enough for a 5 gallon batch full boil, please clarify.....
 
Sorry, this last post is causing me major confusion. You tried to mash a 1.10+ grain bill in a 5 gallon cooler? You don't want to boil down 10gallons of wort in a 8 gallon kettle? The math here is not adding up here which makes answering your questions even more difficult as to why things didn't turn out.

A 5 gallon MLT will get you a 1.060 beer and an 8 gallon kettle is barely enough for a 5 gallon batch full boil, please clarify.....


Oops! My mash tun cooler is 10 gallons, not 5. I apologize for the confusion.
 
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