Brewday: “Calibration” Amber Ale

February 1, 2010

My dad works for an analytical chemistry lab, which includes nutritional analyses on grains and animal feeds. To grind the grains for testing they use Romer Mills, motorized mills that crack the grains, mix them to homogeneity, then subsample them. He found a couple that had been put in storage and had been replaced, so he brought one home for me to see if it could help with my brewing. Heh, no question there! 🙂

I haven’t had much time to brew lately with work and other stuff getting in the way, but I’ve been wanting to make a batch to calibrate how much efficiency I get with the new mill. I finally had some free time today, so I threw together a recipe with ingredients I had on hand and made a “Calibration” Amber Ale. Not only did I dial-in my extraction efficiency, but I learned I had another aspect of my system understood wrong.

“Calibration” Amber Ale

  • 9 lbs Maris Otter malt
  • 3/4 lb CaraAroma malt
  • 1 lb Dark Munich malt
  • 3/4 oz Galena hop pellets for 60 minutes (11% Alpha Acid)
  • 1 oz Galena hop pellets for 15 minutes
  • 1 oz Galena hop pellets at the end of the boil
  • 1 tsp Wyeast yeast nutrient for 15 minutes
  • Wyeast 1272 American Ale II Yeast
  • Mashed at 156 degrees for 60 minutes at 1.25 qt/lb

Because I had absolutely no clue what efficiency I’d get with the new grain mill, I measured the wort’s gravity before the boil so I could adjust my hop levels so I wouldn’t go overboard with them. Pre-boil gravity was 1.044 with 6.5 gallons of collected wort from the mash. Assuming 1 gallon lost to evaporation in the boil, that would leave me with a gravity of ~1.052 in 5.5 gallons, which would be 70% efficiency and exactly what I was hoping for. When I measured the gravity at the end of the boil, it was 1.056 and I had half a gallon less than I expected. I try to overshoot my volumes so I can leave about half a gallon in the brew pot and leave all the settled proteins out of the fermenter, so 5.5 gallons was what I was shooting for. I got 5 gallons, 4.75 in the fermenter and 0.25 left in the pot. The lower volume and higher gravity show I got the 70% efficiency I had calculated, but I’ve been underestimating my boil-off losses. That would explain why my volume calculations always seem off.

The whole brewday took 4 hours from milling the grains to finishing cleanup, which is half an hour better than I’ve ever managed before. All around it was a great day: fast, efficient, using my toy, and learning two things about my system. 🙂

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