Russian Imperial Stout. Getting the FG just right?

[KYdustinj]

So the brew I'm planning on tackling is a Russian Imperial Stout that will be aged on bourbon oak chips. Obviously this will be a very big beer. Due to my lack of equipment to accommodate this brew, I'm going to be doing partial BIAB/partial extract.

Here's my planned recipe:

6lbs. Light DME
4lbs. Amber DME
3lbs. Munich DME

2lbs Chocolate
1.5lbs Roasted Barley
1lbs. Caramel 60L
.5lbs Black Malt

I plan on mashing at 156*F for 1 hour.

4oz magnum hops (60 min boil)

I conjured up this recipe on the Brewer's Friend Recipe calculator, figuring about 70% efficiency, to get the OG and FG that I wanted.

The recipe calculator estimates an OG of 1.131 and a FG of 1.037. The OG is perfect, and I want a FG of about 1.040. Knowing that there will be unfermentables left from the extract I tried to take that into consideration.

My dilemmas:

1. Does 70% seem too high for an efficiency of this recipe?

2. I trust the site's prediction for OG, as I ran a couple of my tried and tested recipes through and got near perfect accuracy. But, I'm worried about the FG prediction. I've heard that to get this beer perfect, the FG should not go below 1.036 or above 1.040. Now, I had just expected to use the White Labs San Diego Super Yeast, but according to the calculator that will take the FG too low. Instead, safale US-05 seems to be the yeast to get this brew right where I want it. DOES THAT SEEM RIGHT?

3. Please offer critiques of the recipe and suggestions for changes. What can I do to help ensure I get the right OG and FG? (i.e., change mash temp, mash time, etc.?)

4. P.S.- For those of you who have aged on bourbon oak chips, how long would you allow the beer to remain on the chips? I'll be racking from primary onto the chips in a secondary.

 

[peterj]

I don't think you need to worry about the FG being too low. Especially since all of your fermentables are coming from extract which has a high proportion of unfermentables in it in the first place. I would be trying to get it as low as possible. An FG in the 1.030-1.040 range is going to be REALLY sweet. I would think that would be too cloying. And with that much extract and that high an OG, you are probably looking more in the 1.040-1.050 range for an FG.

Also, none of the grains you listed have any diastatic power, so it won't really be a mash, you'll just be steeping.

I would lower the OG down to around 1.100-1.110 and consider replacing some of the extract with corn sugar.

 

[zachattack]

I'll give you what answers I can:

1. Does 70% seem too high for an efficiency of this recipe?

You don't need to mash, just steep, these are all specialty grains that will provide little to no fermentable sugar. Since all your fermentables are coming from the extract, I don't think efficiency is relevant.

2. I trust the site's prediction for OG, as I ran a couple of my tried and tested recipes through and got near perfect accuracy. But, I'm worried about the FG prediction. I've heard that to get this beer perfect, the FG should not go below 1.036 or above 1.040. Now, I had just expected to use the White Labs San Diego Super Yeast, but according to the calculator that will take the FG too low. Instead, safale US-05 seems to be the yeast to get this brew right where I want it. DOES THAT SEEM RIGHT?

Fermentability/FG is very hard to control with extract. One thing that might help is to use a 100% base malt extract, for example Northern Brewer's Marris Otter syrup. That way you avoid the inevitable carapils and other C-malts that are in most extracts, and it gives you a blank slate so you can control all the specialty malts. You might want to consider replacing some of the extract with table sugar to bring down the fermentability, though I agree that you want this to finish on the higher side. But you definitely don't want it to stall out at 1.050 or something.

In terms of yeast, I'd do 2-3 rehydrated packs of US-05, if that doesn't finish where you want you can try a different yeast.

3. Please offer critiques of the recipe and suggestions for changes. What can I do to help ensure I get the right OG and FG? (i.e., change mash temp, mash time, etc.?)

All the grains are specialty grains (with no diastatic power) so you really aren't mashing. Time/temp isn't too critical. With extract as long as you measure everything properly and control your volume there's no way to miss your calculated OG.

4. P.S.- For those of you who have aged on bourbon oak chips, how long would you allow the beer to remain on the chips? I'll be racking from primary onto the chips in a secondary.

Use cubes, not chips, and plan on 1-6 months tasting along the way. Read this thread and the linked podcast:
https://www.homebrewtalk.com/f13/tips-wood-aging-119445/

 

[evrose]

I think you may have a little confusion on what your process is... All of your fermentables are DME. This technically isn't BIAB, it's an extract brew with specialty grains. You don't "mash", you just steep. 30 min in the 150's for the grains will be fine. Mashing is a process where fermentable sugar is extracted from grain. That's not happening in this recipe. There's no enzyme conversion taking place, so you really don't have to worry about efficiency. Efficiency only comes in to play when you are getting your sugar from grains, your sugar is coming entirely from the DME.

An OG of 1.131 to a FG of 1.037 is an attenuation of 71.76% (ABV of 12.31%). Assuming good fermentation conditions, S-05 will attenuate a bit more than that (leading to a lower FG). But 1.037 is a pretty sweet final beer... I'm not sure I'd want to go lower. I'd use WLP090, it's more tolerant to high alcohol levels, but you'll need a MASSIVE starter, or multiple vials.

 

[peterj]

Use cubes, not chips, and plan on 1-6 months tasting along the way. Read this thread and the linked podcast:
https://www.homebrewtalk.com/f13/tips-wood-aging-119445/

+1 to cubes. It takes longer, but it is a much rounder flavor. And this should age for a while anyway so the extra time of cubes vs chips won't matter too much.

I wasn't aware that Northern Brewers Maris Otter syrup didn't have any carapils in it. That's great! When I used to brew with extract, I always hated how they would add carapils to every extract on the market. Never made sense to me.

 

[Stirs]

I did one 10 months ago and it's still ageing. It took forever to ferment all those sugars and had to repitch three times. I'm planning on transferring off the chips sometime soon.

 

[KYdustinj]

I don't think you need to worry about the FG being too low. Especially since all of your fermentables are coming from extract which has a high proportion of unfermentables in it in the first place. I would be trying to get it as low as possible. An FG in the 1.030-1.040 range is going to be REALLY sweet. I would think that would be too cloying. And with that much extract and that high an OG, you are probably looking more in the 1.040-1.050 range for an FG.

Also, none of the grains you listed have any diastatic power, so it won't really be a mash, you'll just be steeping.

I would lower the OG down to around 1.100-1.110 and consider replacing some of the extract with corn sugar.

Ok, thanks. Just to be clear, this recipe is loosely based on the Bourbon County Stout, which is fairly sweet with a fg of about 1.040 and an og of about 1.13.

So would you still steep the grains for 1 hour?

And what are your thoughts on the yeast selection?

* VOID this response. Answers were coming in as I began to type. Thanks again peterj.

 

[Hopper5000]

Agreed with everyone else on the steeping vs mashing. If you want to do a mini mash yo have to add at least a few pounds of 2 row in there, but even then it might be hard for the enzymes to convert with that much specialty grain. Generally also with larger beers you don't want to mash that high as there are enough residual sugars left over to give it plenty of body. I believe most folks go in the 150 to 153 range for RIS's. I am also wondering how large of a batch you are doing because these numbers seem a bit high for the ingredients vs 5 gallons.

I prefer my RIS's to finish in the low 20's because I don't like mine too sweet. If you truely are going to start with that high of an OG us-5 probably won't be able to handle that much alcohol.

IMHO if you want to make a big beer like this I would use wlp1 and make a huge starter. Starters, aeration, and ferm temp are the most important things on big beers.

You could also make a beer that's under 5% with wlp1 (hey it's summer too) and then pitch your RIS on top of this beer after racking. This would give you plenty of yeast for this brew.

 

[Hopper5000]

As for the aging on the wood, I have never used chips before, only cubes. Chips will infuse very quickly and can get kind of chalky. You really only need to age the beer on chips for a max a month. You will have to taste very frequently like every week or so. Cubes are a bit more forgiving and I have aged with those for about 2 months with pretty good success. Just soak them in some hard alcohol for a few days before throwing them just to make sure you nuke anything that was living on them.

 

[KYdustinj]

Use cubes, not chips, and plan on 1-6 months tasting along the way. Read this thread and the linked podcast:
https://www.homebrewtalk.com/f13/tips-wood-aging-119445/

HMMM... So I have another dilemma I guess. I used to distill quite a bit and make "bourbons". I currently have two different glass gallon jugs, in which I placed toasted oak chips and my distilled spirit. Those two jugs are currently holding "bourbons" that I made and are coming up on 4 years of aging. I'm bottling them next week, and was planning to use the oak chips on which they've been aging to make this beer. Thats the whole inspiration for doing this bourbon RIS at this time.

Any thoughts?

Should I maybe rack onto the chips for let's say two weeks? Then rack a third time into another vessel (empty) for mellowing?

 

[KYdustinj]

Just had another idea...

I have some oak staves and a lid from a woodford reserve bourbon barrel. Maybe I'll chop some cubes from the barrel parts.

What if I place the RIS on my "bourbon" chips for two weeks, then transfer to a vessel onto the woodford barrel chunks for the long haul.

I'm leaving the country for South Africa next month and will be gone for five months. My hope was to have this beer on the oak before I left, then have my girlfriend bottle it about a month before I'm due back. That way it could be about ready when I return in the winter. The perfect time for a bourbon stout.

Any concerns with that?

 

[evrose]

Something like this is likely to take WAY more than a month to carbonate. Way more. You may be able to get it on oak before then, but I'd have her bottle it about three months before you return. That gives you about three months for fermentation and secondary "oaking"... which should be more than enough.

 

[KYdustinj]

OK. So here's the plan so far. Brew day is on Sunday, maybe monday. I began a yeast starter on Tuesday and have stepped it up to now 3 litres and will cold crash on saturday. I used WLPO99 (super high gravity), I couldn't find any WLP090 in Lexington at the moment. Remember that I want this beer to end with an FG between 1.037 and 1.040. My proposed recipe is at the start of this thread, the exception is that I'm dropping the amber from 4 lbs to 3 lbs and adding 1 lb corn sugar instead. I'm also switching the amber to LME from DME. I know this is going to be tough to get spot on. The recipe calcuator estimates it to finish at 1.020, but I'm counting on lots of unfermentables. Does this sound as though it will work? I would rather this finish in the 1.020-1.030 range, than the 1.040-1.050. The other option is that I do have two packets of dry safale US-05 in the fridge that I can rehydrate and pitch instead, but I'm worried about its tolerance with the alcohol level.

Any thoughts?

 

[KYdustinj]

Ok. So, I solved my yeast issue fairly quickly. I went for the two packets of rehydrated US-05 and its been going to town on this beer for the past three days pretty relentlessly. Originally I was shooting for an OG of about 1.131. Insteady I ended up with 1.115, so I decided the US-05 was better since I'm certain the P099 starter would have taken this beer too low.

Now, the question is how did my OG get so far off the mark?

I can see two option that lead to the failure. I could'nt find munich LME so instead opted to do a mini-mash with 6lbs of crushed munich. I mashed the grains in my brew kettle with a large nylon bag at 152-155 for an hour in 2 gallons of H20. I then lifted the grains above the kettle into a strainer and sparged with 6 qts of 170*F H20.

The second option came when I stepped outside to take my grains to the compost. When I came back in there was girlfriend on her hands and knees glaring at me very unhappily, as she was cleaning up the mess. I had had my first boil over. It was messy, but not all that bad. Are the sugars very concentrated in the foam of a boil over? Would that be the most likely culprit for me to miss my OG by that much? Or is it more likely that I had an inefficient mash?

 

[Hopper5000]

Do you know what your efficiency was for your minimash? It could have been poor which is why you didn't end up with your target OG. Also, if you could have gotten a higher volume of wort than you anticipated. There's also hop absorbtion and cold/hot break. I don't think it was the boil over, unless you lost like a half gallon or something.

 

[peterj]

The boil over shouldn't have an effect on efficiency. The foam is largely made up of proteins that are precipitating out because of the boil. Sometimes I'll scoop the hot break off the top and dump it as it forms.

My guess is your mash. I'm guessing you did your mash with the Munich and the specialty grains as well (if you just did 6lbs munich then your wort gravity from your mash would only be around 1.050 or so and that would be your problem). You may have set it up on paper so that you would end up with 1.131 wort from your mash, but efficiency drops drastically when you are mashing very high gravity beers. I believe I heard once that it isn't possible to extract wort from a mash past a certain gravity, but I can't remember what the number was. I'm know it was less than 1.131 though. Maybe around 1.090. People will often boil longer or add malt extract to get the wort higher. So my guess is that the wort that you got from the mash was much lower gravity than you expected and diluted your final wort to 1.115.

 

[KYdustinj]

The boil over shouldn't have an effect on efficiency. The foam is largely made up of proteins that are precipitating out because of the boil. Sometimes I'll scoop the hot break off the top and dump it as it forms.

My guess is your mash. I'm guessing you did your mash with the Munich and the specialty grains as well (if you just did 6lbs munich then your wort gravity from your mash would only be around 1.050 or so and that would be your problem). You may have set it up on paper so that you would end up with 1.131 wort from your mash, but efficiency drops drastically when you are mashing very high gravity beers. I believe I heard once that it isn't possible to extract wort from a mash past a certain gravity, but I can't remember what the number was. I'm know it was less than 1.131 though. Maybe around 1.090. People will often boil longer or add malt extract to get the wort higher. So my guess is that the wort that you got from the mash was much lower gravity than you expected and diluted your final wort to 1.115.

After the minimash with the 6lbs of Munich, I brought the the temperature to 158*F and steeped 1lb chocolate, 1 lb roasted barley, 1 lb de-bittered black, 1 lb special b, and 0.5 lb crystal 60L for 30 mins. I then brought the wort to a boil and added 6 lbs extra light DME, 3 lbs Amber DME, and 1 lbs Light DME. After that came the boil over. But, if ya'll think that the boil over would not have really affected the OG that much, it must have been the efficiency with my minimash. I even told myself to take a gravity reading after the minimash to see what I got from the 6lbs of munich for future reference, but convinced myself it would be fine and come close. I used a recipe calculator on brewer's friend to calculate what I needed for the OG of 1.131, expecting a 3 gallon boil and a final volume of 5 gallons.

So what factors would have contributed to a low gravity in the minimash? I placed the 6lbs in a nylon grain bag and dropped it into the 2 gallons at 170*F in order for it to drop around 152-155*F. Every ten minutes or so I checked the temp and swirled the bag around a bit. Is it possible for the bag to be too compacted?

Thanks for all your help so far guys. It's just frustrating, especially since this was my first mash attempt, and I thought I had followed all the rules and procedures with my type of set up.