Jul 19, 2008

Slightly Oilier Bohunk

My brewery witnessed a major improvement this week with the addition of a chest freezer to control fermentation temperatures. Originally I was planning on brewing a Bavarian Lager similar to Bittburger or Ayinger's Jahrhundert, but the hops I need are unavailable. Fortunately Saaz are, so I will be making some Bohemian Pilsner. (later) As you will see, the gravity ended up being well higher than the mark, so this does not qualify as a Bohemian Pilsner.

Target Gravity = 1.055

O.G. = 1.068
F.G. = 1.016
ABV = 6.8%

Target IBU = 40

Malt Bill:

80% Pilsner Malt -- 10.5 lbs
10% Munich I -- 1.3 lbs
5% Carapils -- .7 lb
5% Carahel -- .7 lb

Hop Schedule:

1 oz Sterling (7% AA) -- 75 minutes
1 oz Sterling (7% AA) -- 45 minutes
1 oz Saaz (3.4 % AA) -- 15 minutes

I am going to try another multi-step mash like the one I used with the Gold Glove Leapday Ale. There will be two steps: a protein rest for 30 minutes @ 144 degrees, and then an hour @ 156. Here is the equation I will use:

Initial Infusion Equation:
Strike Water Temperature Tw = (.2/r)(T2 - T1) + T2

Mash Infusion Equation:
Wa = (T2 - T1)(.2G + Wm)/(Tw - T2)

r = The ratio of water to grain in quarts per pound.
Wa = The amount of boiling water added (in quarts).
Wm = The total amount of water in the mash (in quarts).
T1 = The initial temperature (¡F) of the mash.
T2 = The target temperature (¡F) of the mash.
Tw = The actual temperature (¡F) of the infusion water.
G = The amount of grain in the mash (in pounds).
Initial Infusion:

(.2/.75)(144-75)+144 =
(.2666)(69)+144=162 degrees

13.2 lbs of grain x .75 quarts = 9.9 quarts / 2.5 gallons of 162 degree water

Mash Infusion:

(156-144)(26.4+9.9) / (210-156)
(12)(36.3) /54
435.6 / 54 = 8 quarts / 2 gallons boiling water

30 minutes in: The temperature was reading a little under 130, so I have no idea about what happened. I went ahead and added the 2 gallons of boiling water, and set the timer for another 30 minutes. I will then check out what is going on and see if another step infusion is needed. I probably should have used more than .75 quarts per pound of grain.
59 minutes in: I get three different temperature readings with three different thermometers. One says 138; one says 152; one says 158. AHHHHH!
61 minutes in: I just compared three thermometers in a pot of water that was already on its way to boiling, and they read the same. I then checked my mash with one of the thermometers other than the one I leave in there, and I got a reading of 158 -- two degrees hotter than I wanted. I am going to go with this. Maybe leaving the thermometer in the mash is a bad idea.

Reflections of the Brewday: I learned a thing or two today. First, I think leaving the thermometer in the mash is the source of much unnecessary stress. The other two thermometers (which measured the same as the one in the mash when placed in 100 degree water) showed that the one left in the mash was inaccurate since it read differently than the other two when they were placed in the mash. Secondly, running off my wort too quickly was certainly the reason for my shitty efficiency -- so much that this beer will turn out much stronger since I calculated for 70% efficiency, a lower figure to compensate for my poor performance of late, and I ended up being 79% efficient. I am not complaining at all about that. It is better to figure out what what causing poor efficiency than hit a target gravity on the nose. I will next time. The original gravity of this batch ended up being 1.068, when I was planning for 1.055. This also means I will need to recalculate the IBUs for this one since the wort was denser than I figured for.

10.6.08 -- Figured that if I want to start my diacetyl rest 75% of the way through fermentation, I should turn the temp up once the gravity reads 1.031. (68 GU x .74 attenuation = 18) -- (31 is 25% of the way from 18 to 68, thus a gravity reading of 1.031 would denote 75% fermented.)
10.10.08 -- Used new "thief" to check gravity. 1.041.
10.13.08 -- Refigured IBUs (58.53) while sanitizing my "thief" and found that I was way off on my math originally (left out an important zero), so this beer will be way hoppier than expected. Since the beer will be stonger too, the GU:BU ratio still fits a Bohemian Pilsner (.86). Later: gravity measures 1.032 right now. I turned the temp up to around 68. Will probably rack to primary in a couple days.
10.17.08 -- Racked into secondary and placed in freezer at 34 degrees. I will leave it here as long as I can, knowing that if I need the room in the freezer, I can keg it and put it in the fridge which is at 40 degrees.
11.14.08 -- Measured final gravity at around 1.016 and then kegged. May be a bit early, but I had to make room in the chest freezer for Munich Dunkel
11.21.08 -- Debuted this beer a night or two ago, and I am very impressed. The head retention is wonderful, yet the beer still needs to clear a little -- probably due to a little collection of yeast that has settled to the bottom of the keg. The beer has wonderful body, perhaps more than a Bohemian Pilsner should, but with the O.G. I ended up with, seems appropriate. Hop level seems to be where I want it too.
12.26.08 -- Blew out before I could get a good picture.

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