Russian Imperial Stout partial mashening (and other stories)

[GRJBowers]

Hi, HBT. Longtime lurker finally signed up for some advice and apologies in advance for what will probably be a wall of text.

First some background info. I don't have an outdoor burner so my homebrew adventures are limited to partial mashes in a 5 gallon cooler with partial boils on the stove top. When I want to adapt an all-grain recipe, I try to mash all the specialty grains with enough base malt to convert all of the starches, then make up the rest of the gravity with malt extract.

Which leads me to this recipe (based off https://www.brewersfriend.com/homebrew/recipe/view/255745/russian-imperial-stout):

2.75 lbs 2-Row
1.25 lbs roasted barley
1 lb Special B
0.75 lb pale chocolate
0.5 lb CaraFoam
6.6 lbs light LME
3.3 lbs Munich LME
0.2 lbs light DME (or however much I need to reach 1.092 sg)

1.375 oz Magnum (@ 13% AA) 60 minutes 65.94 IBU
1 oz Fuggles (@ 5% AA) 5 minutes 3.44 IBU

Nottingham or S-04 yeast (haven't decided yet)
CBC-1 for bottle conditioning

Predicted OG: 1.092
Predicted FG: 1.021
Predicted ABV: 9.25%
Total IBU: 69.37 IBU

This will go on some Hungarian oak cubes for a while (will determine how long by taste), and then it will be aged for at least 6 months.

The first thing I need advice on is water. I use RO water and build the water from there. Because of the amount of roasted malt, the pH of the mash water is pretty low (well below 5).

My target water profile:
120 ppm calcium
4 ppm magnesium
12 ppm sodium
55 ppm sulfate
19 ppm chloride
315 ppm bicarbonate

Mash additions:
0.8 g gypsum
0.3 g calcium chloride
0.5 g Epsom salts
2.1 g baking soda
2.4 g calcium hydroxide

With 3 gallons of mash water that gets me to the following:
141 ppm calcium
4 ppm magnesium
59 ppm sodium (high but should be below the flavor threshold)
56 ppm sulfate
21 ppm chloride
498 ppm bicarbonate (really, really high. Reason for concern?)
Residual Alkalinity: 408 ppm as calcium carbonate
pH: 5.21

As I mentioned, I use a 5 gallon cooler for mashing. So with the grain bill as is, I can only use about 3 gallons for mashing so dilution of the mash water to bring the concentrations down isn't really an option. Reducing the baking soda addition would bring the sodium and bicarbonate levels down but the pH would decrease to below 5.2, which as I understand is sort of the minimum pH for a good mash.

I guess my main question about the water is whether or not the bicarbonate level is a cause for concern? The high sodium level I can deal with.

The second question is about preparing the oak cubes. I'm not a fan of bourbon or rum, so soaking the cubes in either of those in advance isn't really something I want to do. For sanitation I was thinking of either boiling them for a few minutes or soaking them in vodka for a few weeks beforehand, which option would work best?

And finally the third question is one of yeast. I have Nottingham and S-04 on hand but I can get liquid yeasts with some legwork. What yeast would work well for a beer this big.

Thanks for any help.

-Bob

 

[EtchyLives]

I'll answer your question about cubes and yeast. I'm curious as well about any answers regarding bicarbonate.

Cubes: vodka is what I would use to sanitize, although boiling would work, too. I would use vodka because it's neutral and you'll get all the oak flavor without the chance of boiling the flavor out.

Nottingham: yes. That's what I use for my big stout. It's a fermenting beast and you can get a wide variety of flavors by varying your temp. I've fermented using Nottingham up to 10% with no issues. Aerate, a little yeast nutrient, and a healthy sized pitch using your favorite yeast calculator.

 

[GRJBowers]

I'll answer your question about cubes and yeast. I'm curious as well about any answers regarding bicarbonate.

Cubes: vodka is what I would use to sanitize, although boiling would work, too. I would use vodka because it's neutral and you'll get all the oak flavor without the chance of boiling the flavor out.

Nottingham: yes. That's what I use for my big stout. It's a fermenting beast and you can get a wide variety of flavors by varying your temp. I've fermented using Nottingham up to 10% with no issues. Aerate, a little yeast nutrient, and a healthy sized pitch using your favorite yeast calculator.

Thanks for the info. Would you throw out the vodka, or throw it in with the cubes?

 

[EtchyLives]

Throw it in with it. The slurry will keep the oak flavor in the beer. Or at least that's what I think

 

[EtchyLives]

Also, I reviewed the stats on Nottingham. It's good up to 14%. Also, it's dry, so keep in mind that I use two packets of properly hydrated yeast (86-95° water, prepped per the instructions from Lallemand) in my beers. I'm no expert but doing this has created a smooth, robust RIS with no off flavors that aged perfectly for 6+ months. I used bourbon to prep the oak but see my previous notes on why I would use vodka for your situation/desires.

 

[Rivcyclist]

Hi Bob, I also use a 5 gallon cooler for a mash tun and use extract to make up for everything. Earlier this year I made a RIS and it turned out great. I used much more grain than your recipe with like 1.15 quart per pound, and then turned to Dark LME to fill out the rest. Also -- I used a 2 liter starter of Wyeast 1056 with 2 steps, and oxygenated the heck out of the wort with a pump. It's vital to get enough yeast in there to eat all the sugars and to provide plenty of 02 to help em' out.

Here's what I did:


Liquid Malt Extract - Dark
7 lb
American - Pale 2-Row
7 lb
United Kingdom - Carastan (30/37)
1 lb
American - Caramel / Crystal 120L
0.75 lb
American - Chocolate
0.5 lb
United Kingdom - Brown
0.5 lb
American - Roasted Barley
0.3 lb

3 oz
Cluster 60 min

1 oz
Northern Brewer 5 min

1 oz
Centennial 5 min

I mashed at 151, OG came out at 1.106, FG got down to 1.029 so around 10%abv.
I should have probably used less LME, this RIS was pretty 'hot' on the alcohol for the first few months, but at month 4 that subsided and it turned out great. I ended up kegging it instead of bottling. I also did not use oak since I liked it so much as it was, but next time I plan on using oak cubes to see what that's like. Good luck, let us know how it works out.

 

[GRJBowers]

Hi Bob, I also use a 5 gallon cooler for a mash tun and use extract to make up for everything. Earlier this year I made a RIS and it turned out great. I used much more grain than your recipe with like 1.15 quart per pound, and then turned to Dark LME to fill out the rest. Also -- I used a 2 liter starter of Wyeast 1056 with 2 steps, and oxygenated the heck out of the wort with a pump. It's vital to get enough yeast in there to eat all the sugars and to provide plenty of 02 to help em' out.

Here's what I did:


Liquid Malt Extract - Dark
7 lb
American - Pale 2-Row
7 lb
United Kingdom - Carastan (30/37)
1 lb
American - Caramel / Crystal 120L
0.75 lb
American - Chocolate
0.5 lb
United Kingdom - Brown
0.5 lb
American - Roasted Barley
0.3 lb

3 oz
Cluster 60 min

1 oz
Northern Brewer 5 min

1 oz
Centennial 5 min

I mashed at 151, OG came out at 1.106, FG got down to 1.029 so around 10%abv.
I should have probably used less LME, this RIS was pretty 'hot' on the alcohol for the first few months, but at month 4 that subsided and it turned out great. I ended up kegging it instead of bottling. I also did not use oak since I liked it so much as it was, but next time I plan on using oak cubes to see what that's like. Good luck, let us know how it works out.

I like the idea of using the dark lme instead of light. It would make the water chemistry less of an issue. Thanks.

 

[GRJBowers]

Update to this thread. I've finally got around to brewing this recipe hitting an OG of 1.102 (quite a bit higher than expected) and made a few of changes.

1) Extended the boil time to 90 minutes to reduce the volume to make room for the LME.
2) I used WLP028 Edinburgh Scottish Ale yeast instead of the Notty or S-04. Made a two-stage starter pitching about 1.01 Cells/mL/°P.
3) Used slightly less Magnum since they were slightly higher AA than the recipe values.

After 3 days it was already down to 1.045. It has been in the fermenter for 2 weeks now and seems to have stopped at 1.041. Only about 60% apparent attenuation and 9% ABV. I don't expect it to change much in the next week when I originally intended to put it on the oak cubes. This leads me to yet more questions.

1) Did I somehow create more unfermentable sugars with a 90 minute boil?
2) If not, have I simply maxed out the yeasts alcohol tolerance (listed as 8-12% by White Labs)?
3) If that's the case will adding the CBC-1 at bottling start fermenting any sugars that are still there?
4) Should I add the CBC-1 when I put in on oak to see if it ferments to avoid any bottle bombs come bottling time?
5) should I give it more than another week in the fermenter if the gravity doesn't change?

 

[GRJBowers]

Figured I'd update this thread with the current status of this brew.

I ended up leaving the beer in the primary for another week and the gravity stayed at 1.041. I steamed 1 oz of medium toast Hungarian oak for a few minutes to sanitize them and put them in a 3 gallon carboy and filled the carboy with beer. I then bottled the rest primed with enough sugar to give me about 2.3 volumes of CO2.

I sampled the unoaked beer 2 weeks later (and a few more a month later). It was a little undercarbed for my liking. Flavor-wise it's all roast. Lots of coffee and dark chocolate. If there was any contribution from the Special B and Munich LME, I couldn't taste it. Not much to say about the bitterness other than it was nice and clean like intended and it seems to counteract the high FG. Hopefully the bitterness doesn't fade too quickly and make this one too sweet.

I left the oaked portion on the oak cubes for 3 months. Checked the gravity after those 3 months and it had dropped to 1.039. Come bottling day I added about 2 grams of CBC-1 to the bottling bucket (in hindsight I should have rehydrated it first) along with enough priming sugar for 2.4 volumes of CO2. Compared with the unoaked version, it is more bitter, though I might be mistaking tannic astringency for hop bitterness.

I'll let the oaked one sit for a few months and try it again, probably around Christmas, to see how it develops.