Lager Split Batch

>> Sunday, December 20, 2020

Today I'm brewing a 10 gallon batch to test out my newly acquired Blichmann 20 gallon Mash Tun. The recipe today is based on the Bierstadt Slow Pour Pilsner recipe I brewed a while back. This one will be a split batch with 5 gallons going on Saflager 34/70, and 5 gallons going on White Labs 940 Mexican Lager. I'm also trying a different base malt. Here's the recipe as I'm brewing it today.

Batch size: 10 gallons
Target OG: 1.047
Target FG: 1.012
IBU: 33

18.0# Great Western Pure Idaho Pilsner
1.0# Weyermann Acidulated Malt
2.0g BrewTan B (dissolved in warm water, mash)
56.6g Hallertau Mittelfrüh (FWH), 3.1% AA
113.2g Hallertau Mittelfrüh (70 min) 3.1% AA
84.88g Hallertau Mittelfrüh (5 min) 3.1% AA
Wyeast Nutrient
9.32g BCAA (Dissolved in water or wort, 5 min)
1 Whirlfloc
Saflager W-34/70
WLP 940 Mexican Lager

The first step is a protein rest @131F for 10 min.

The second step is @144F for 30 min.

The third step is @160F for 40 min.

Finally, pull a 1/3 decoction (thin), bring to a boil, and boil for 10 min.

Return decoction to main mash and vorlauf until clear.
Collect about 9-9.5 gallons, then top up to a boil volume of 11.75 gallons.

90 min boil. 34/70 half gets chilled to 47F, and ferments at 47F. The WLP940 half gets chilled to 49F, then I'll bump it up 1F per day for the first three days. 

Perform diacetyl rest when gravity ~1.017.

Water Profile - For each gallon of RO brewing water, add:
0.38g Gypsum
0.32g Epsom Salts
0.49g Calcium Chloride

Brewing Notes
No major issues, but I'm pooped. During the boil, I went ahead and kegged both of my Fruited Farmhouse Ale (Peach/Apricot and Blackberry). 

I added about 1.5ml of phosphoric acid, pretty much because I was in autopilot. Because I used acid malt, I definitely didn't need as much phosphoric acid as I'd normally use, so the mash pH was lower than I usually shoot for. Here are some of the vitals:
  • Beginning mash pH 4.99.
  • Mash pH of 5.10 right before pulling decoction.
  • OG 1.052
OG was definitely a little closer to target this time. The mash tun worked well but I did notice the wort didn't clear as much as with my original mash tun. I suspect it's because even though this was a 10 gallon batch, the grain bill wasn't huge and therefore the grain bed wasn't very deep. I had a great hop cone at the end of the whirlpool. I'm currently chilling down to my pitching temperatures.

Update 12/22/2020
I pitched the yeast yesterday morning. Both halves are actively chugging away this morning.

Update 12/29/2020
Both fermentors are chugging along. I decided not to do a diacetyl rest on the 34/70 half, per the original recipe from BYOB. Both will probably stay in the fermentors for at least another week.