Sunday, June 6, 2010

Zestfully clean

After brewing 20 gallons over the last two weekends, I didn't plan much for this week. About all I accomplished was the kegging of 15 of those 20 gallons and a little cleanup.

Kegged: 100501 Geordie-Boy Ale

Interestingly, the gravity samples of the two carboys tasted different even though they both used the same yeast. It could just be that the first sample taste was my first beer of the day, and by the time I tasted the second sample my taste buds were already aligned. We'll see when it comes to serving time. Both of them fit within my expectations for the house brown ale.

The second sample came from the first carboy to take off in fermentation. Its FG was 1.014, for an ABV of  4.43%. The other sample, with the delayed fermentation, came in at 1.013 for an ABV of  4.56%. Isn't it interesting how a single gravity point moves that number so much. I'm going to have to look into the math for that calculation.

Kegged: 100502 Honey Half-Wit

I was a little apprehensive about kegging this one because it looked like there was still a foamy surface on the beer in the carboy, but as I pulled it up to rack it, I noticed that the foam was mostly CO2 bubbles that had aggregated against the floating orange zest. The sample had a pretty good flavor to it, and I definitely tasted a citrusy overtone from the orange. I think this one will be a winner. As it happened, this is the first batch I have had that finished below 1.010, coming in at 1.009 for an ABV of 4.03%.

Good thing I took three semesters of calculus in college

Going back to the ABV math for a second: The Geordie-Boys started at 1.048 and attenuated 34 and 35 points, respectively, to finish at 1.014 and 1.013, giving them ABVs of 4.43% and 4.56%. The Honey Half-Wit started at 1.040 and attenuated 31 points to 1.009 for an ABV of 4.03%. If one point of attenuation is worth .13% ABV, as the Geordie-Boys indicate, then linear interpolation would predict the Honey Half-Wit to be 4 x .13% = .52% lower than the 4.56% of the 1.013 Geordie-Boy, or 4.04%. Pretty close. I will have to dig around in some references to see if that's how it really works or if there's something else involved.