Scaling Down an Imperial Stout

Brewing Processes
1

So a few months ago I brewed, IMO, a fantastic Imperial Oatmeal Stout.  It ended up being 8.4%.  Now, I’d like to scale it to a 6% beer, it was so freakin good, I just wanted to keep drinking it, but my wife probably wouldn’t like that!!  My question is, do I need to scale the hops or anything else, besides the base malt, down so it doesn’t get overpowering?  Or would just scaling the base malt down make it even more flavorful?

Imperial Oatmeal Stout  (5.5 gal)

0.25 lb Rice Hulls (0.0 SRM) Adjunct 1.47 %
11.20 lb Pale Malt (2 Row) US (2.0 SRM) Grain 66.08 %
2.00 lb Barley, Flaked (1.7 SRM) Grain 11.80 %
1.00 lb Oats, Flaked (1.0 SRM) Grain 5.90 %
1.00 lb Roasted Barley (300.0 SRM) Grain 5.90 %
1.00 lb Special Roast (50.0 SRM) Grain 5.90 %
0.50 lb Chocolate Malt (350.0 SRM) Grain 2.95 %

3.28 oz Styrian Goldings [5.40 %] (60 min) Hops 53.9 IBU
1.50 oz Chinook [13.00 %] (10 min) Hops 21.5 IBU

0.11 tsp Fermcap -use 2-3 drops (Boil 60.0 min) Misc 
1.10 tbsp PH 5.2 Stabilizer (Mash 60.0 min) Misc 
1.10 items Whirlfloc Tablet (Boil 15.0 min) Misc 
1.10 tsp Yeast Nutrient (Primary 3.0 days) Misc

1 Pkgs SafBrew - US 05 (Fermentis)

OG 1.082
FG 1.018
ABV 8.38%

2

You want to scale the hops also.  Try and keep the BU:GU (Bittering Units to Gravity Units ratio) roughly the same.

3

+1

As far as scaling down the recipe I’m not sure I would only adjust the base malt.  If you only adjust the base malt the percentage of other malts will go way up and throw off the balance.  I would adjust the amounts of all the grains but keep the same percentage of the grist for each one.

Happy Brewing,
Brandon

4

Either one of the approaches above will make a good starting point, but I think you might end up adjusting it over a few batches to dial it in to your tastes.  But you have to start somewhere.

5

I’ve done this with a couple of different beers and haven’t found the perfect answer (see Tom’s comments). This situation is where promash excels -

67.1%  8.22 lbs. Pale Malt(2-row)              America        77.91      2
12.0     1.47 lbs. Flaked Barley                 America        69.25      2
 6.0     0.73 lbs. Flaked Oats                   America        71.41      2
 6.0     0.73 lbs. Roasted Barley                America        60.59    450
 6.0     0.73 lbs. Special Roast Malt            America        71.41     40
 3.0     0.37 lbs. Chocolate Malt                America        62.76    350
 2 oz.    Styrian Goldings                  Whole    5.40  57.6  60 min.
 1.10 oz.    Chinook                           Whole   13.00  23.0  10 min.

that would leave you with an OG of 1.060, IBU of 51

I’m not saying this is what you should do,  just that this is what a total scale down would look like.

  I should have mentioned that the flavor products (alc, ester formation) from fermentation might be noticably different with the scaled down beer

6

Most brewing software allows you to automatically scale a recipe.  Once you enter it, you can adjust the final volume and it will change the amounts of every ingredient to match the new volume.  Very handy, espcially when given a recipe for 120 gal!

7

I forgot about the percentages.  That is the route I will probably take.  I remember getting a recipe from the only local brewpub around here, and that’s what he advised me to do.  The recipe he gave me was for 120 gals.  So I just entered his values into Beersmith and then scaled it using the percentages.  It turned out great!!  Thanks for all the help, and sorry to the above poster…I originally entered this response and then probably deleted the same time he was posting his! :-\  That’s where he got the 120 gallon comment!

8

So I ended up not listening to any of you  ;D, and just scaled down the base malt.  I just sampled it last night and must say, it’s pretty freakin good!  Like I remember it tasting.  Right now it’s at 6.5%, based on my SG.  May lower a couple more points, as there was still airlock activity before I took the hydro sample.

OG - 1.066
SG -  1.016

9

Watch out!  Sean and Denny are gonna gitcha!  ;D