Tuesday, August 17, 2010

Calculating V(T)

So when I brewed the Lawnmower Beer, I wondered about the change in volume of water vs. temperature. That's a pretty straightforward analysis so I used EngineeringToolbox to get some values and made the little calculator below. True, I am assuming that wort behaves like pure water, but for my application I think that assumption is acceptable.

Initial volume [gal]:
Initial temperature [degF]:
Final temperature [degF]:
Final volume [gal]:

Friday, August 13, 2010

Lawnmower Beer

I'm in a low-alcohol session beer stage right now and since it's summer, it's time to make some lawnmower beer. I've always used some version of Jamil's recipe (80% 2-row, 20% Minute Rice) and have had the best results (taste-wise) with the default recipe. Fletty even gave me a 44 at 1st Round of Nationals, even though he panned the beer at the club meeting.

I've got some old 2-row (20+ lbs of it) lying around and I think it is too old; over a year. I kept it sealed and dry, but everything has a shelf life so tomorrow I'll use most of it up. I'll be doing a 10 gallon batch and while my mash tun can handle it, I like to get 12 gal into the fermenter so I end up with 10 gallons drinkable, and that means almost 15 gal in the boil kettle. That's always the balance when I do "10 gallon batches" - how much can I really deal with. I will shoot for 14.25 gal into the kettle, which, with thermal expansion, is just shy of 15 gallons.

Standard American Lager

12 gal into the primary (11.5 actual)

Brew date: 14 August 2010


  • 16 lb 2-row
  • 4 lb Minute Rice


  • 0.5 oz Magnum (10% AA) @ 90 min


  • Saflager 34-70, 0.5 liter starter stepped up with another 0.75 liters
Brewing Notes

Day 0
0630 :: 6.25 gal on for sparge (burner not @ max).
0652 :: Mash H2O @ 149F.
0655 :: Preheat tun with 8 gal hot tap H2O.
0658 :: Mash H2O @ 172F - flame off.
0728 :: Mash H2O @ 159F so mash in.
0733 :: Mash @ 149F.
0748 :: 10.75 gal vorlauf/sparge H2O on full.
0743 :: Mash @ 151F, opened tun @ stirred.
0750 :: Mash @ 151F again ... time to adjust calculation?
0803 :: Vorlauf/sparge H2O @ 100F.
0815 :: Vorlauf/sparge H2O @ 133F, mash @ 151F.
0822 :: Vorlauf/sparge H2O @ 151F.
0833 :: Begin sparge; vorlauf/sparge H2O @ 181F.
0858 :: 14.5 gal on to boil.
0900 :: 10.5 Brix (1.041).
0915 :: 191F.
0920 :: Currently 73F with 88% RH, little to no wind.
0920 :: Boil; hops in.
1035 :: IC and whirlfloc in.
1050 :: Flame off.
1110 :: 80F, so into the fermenter.
1112 :: 11.5 Brix (1.046).

I ran into problems when sparging. My mash tun is 10 gal and with the grain and mash water, 
I was up to almost 8 gallons. When I wen to add my 3.5gal of pre-vorlauf water, I ran into trouble. Same again when I want to batch sparge - 7+ gal of water just won't fit! I need to be better prepared in the future.

I also noted that I gathered more than 14.5 gal of wort, probably about 1-1.5gal more. My guess is that the Minute Rice doesn't absorb the same amount of water as grain, it absorbs less.

Another thing I want to look into. How much does the volume of the wort change with temperature? I start off with 10 gal of 165F wort, then bump it up to 212F, then chill it down to 80F, then ferment at 52F. 

Day 1
0900 :: wort @ 54F, so I decanted the starter and added about 0.5 liter of resuspended yeast.

Day 3
1800 :: Fermentation proceeding.

Day 4 
0630 :: 24 bubbles/min @ 52F.

Day 21 (04 Sep)
Racked into two kegs. The gravity was 1.011. Hopefully that will drop over the next few months of lagering.