Wednesday, February 29, 2012

Partigyle Series: Oatmeal & Imperial Stout

This brew day was my first attempt at a quasi-partigyle brew. (I was excited to use my new 10 gal mash tun and brew with my 2 good friends, Ben and Dan) Let me explain my process and why I chose to go this way, in hindsight it didn't work all that well.

  1.  Mash all the grains at once with a grist that is for an Imperial Oatmeal Stout
  2. Collect the first 2 gals into a separate pot. Measure and reduce to 1 gal.
  3. Sparge until collected 10 gal in main boil kettle
  4. Add 2.25 oz Horizon to bitter 10 gals to 42 IBUs
  5. @ 60 min (Volume 9 gal) - Rack 3.5 gal of wort to chilled keg (w 1.5 gal water)
  6. Boil Remaining 5.5 gal
  7. Add 1 oz Horizon to bitter to 98 IBUs
  8. @ 120 min Rack 4 gals into carboy

My calculations are above. I think I chose to go this method mostly for the mental challenge of working out the procedure. In hindsight, it would have been a lot easier and probably more accurate to just do 2 boils.

One of the big issues with this method is sufficiently cooling the 3.5 gals for the Oatmeal Stout. In the excitement of the day, I just racked the beer straight into the 5 gal corny keg. The corny keg was already filled with 1.5 of cool water. I put this all in a water bath, then ice bath. It did not cool very quickly. If I ever try to do this again, I will rack the 3.5 gals to another pot (easily fit in my old extract stove-top pot) and use the wort chiller in there. Next, I will just buy a couple of gallon water jugs and have them in the fridge. Or I need a counter flow wort chiller.
The other big issue is that I didn't use my hop bag, so there were a lot of hops in the boil. All the trub and hops were racked right into the keg. If there is a next time, I will either use a hop bag or better finally get a good filter for my pick-up tube.
The positive parts about this method is that I saved some extra time to chill (because I use an immersion chiller). I also got more kettle carmelization flavor and minimal better hop utilization for the Imperial Stout.

Recipe: Partigyle Stouts
O.G.- OS - 1.052  RIS - 1.096      F.G.- OS - 1.010  RIS - 1.028               
IBU - OS - 30 RIS - 78  SRM-35   Batch - OS -5 gal RIS -5 gal

Grain Bill (77% Efficiency):
21 lb Maris Otter
2 lb Flaked Oats
1.5 lb Chocolate malt - 350L
1.5 lb Biscuit Malt 
1 lb UK Crystal ~77L 
1 lb Roasted Barley

2 oz Horizon, 9.1%, pellet, 120 min
1 oz Horizon, 9.1%, pellet, 60 min

300 mL of  Wyeast 1469-PC West Yorkshire Ale Yeast - 1 Liter Starter (1/2 in each)
1 vial of White Labs 001 - Cal Ale Yeast - 1 Liter Starter (all in RIS)

Brew Day:
Brewed: 1/15/12

San Diego (Alvarado) Tap Water
1 campden tablet per 5 gal.

Mash Details:
H2O/Grain Ratio: 1 qt/lb
Mash Volume: 7 gal 
Sacc Rest. Temp/Time: 154F @ 60min

Boil Details:
Boil Volume: 10 gal
Boil Time: OS - 60min, RIS - 120 min
Post Boil Volume: 10 gal

Ferment Details:
Ferment Temp: OS - Held ~ 68F, RIS - Started at 65, ramped to 68 over 3 days

On Day 4, I added the 1 gal of reduced first runnings to the 4 gals of RIS. To keep the wort, I poured the boiling wort into a pre-heated 1 gal growler. I left the lid loose for a few hours and then tightened and put into the fridge. I tasted it before adding and it was still syrupy sweet and no off-flavors. I don't know how much could live in 1.220 wort. The fermentation stayed active for about a 10 days.

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