Alcohol Calculation

Robert asked me about the estimated alcohol content of the latest batch. In the past, I've looked this up in a table in How To Brew by John Palmer. I thought it would be handy to find an online calculator instead, so I did some Googling.

There's a slick looking calculator at http://www.brewcraft.com.au/wa.asp?idWebPage=9616&idDetails=117. For our Celebration-style ale, with OG 1.051 and FG 1.008, it says 6.3%. Another calculator at http://realbeer.com/hops/kcalc_js.html says 5.6%. The table in Palmer's book says 5.5%.

These discrepancies set me to searching for not just a calculator, but a formula. At http://hbd.org/ensmingr/, I found this:

Alcohol Level. Given the OG and FG, several empirically derived formulas estimate the alcohol content (alcohol-by-volume, ABV in (ml alcohol)/(ml beer)) of beer. Dave Miller (The Complete Handbook of Homebrewing, 1988, Storey Communications) gives a simple formula, where the easy-to-remember constant (0.75) has dimension of (g beer)/(ml ethanol):
(4a) ABV = (OG - FG) / 0.75

Using that formula, we get 5.7%. I suspect that's pretty close.

Kegged

Kegged last night. Gravity: 1.007 at 65° = 1.008. The enormous sock full of hops barely fit.

Racked

Airlock popping rate over the last week:


Sunday, November 6

9:00 pm: 112 ppm, 64°.


Monday, November 7

8:00 am: 106 ppm, 65°. Krausen invading airlock.


Tuesday, November 8

8:00 am: 70 ppm, 66°.
10:15 pm: 60 ppm, 66°.


Wednesday, November 9

8:00 am: 40 ppm, 65°.
9:30 pm: 28 ppm, 65°.


Thursday, November 10

9:00 am: 18 ppm, 63°
8:45 pm: 16 ppm, 66°


Friday, November 11

9:15 am: 8 ppm, 64°


Saturday, November 12

Racked to conditioning tank. Gravity: 1.008 at 70° = 1.009.

Celebration Ale (Full Grain)

Saturday, November 5, 2005

Recipe from brewery.org:

Source: Craig Rode
Recipe added: 05/16/97
Email: craig.rode@sdrc.com
Yeah, it's a lot of hops. But it's pretty close to SNCA. I get about 27 p/p/g with this recipe, you may want to adjust your grain bill. The 120L crystal adds a caramel sweetness and color that is characteristic of SNCA. Dryhopping is a necessity to pick up the centennial nose. Enjoy! Email me if you try this, I'd like to hear how it goes.
Specifics
Recipe type: All Grain
Batch Size: 5
Starting Gravity: 1.066
Finishing Gravity: 1.015
Time in Boil: 75min
Primary Fermentation: 5 Days
Secondary Fermentation: 10 Days
Ingredients:
· 13 lbs Schrier 2 Row Pale
· 1 lb 120L Crystal
· .5 lb 60L Crystal
· 1 oz chinook 60 min
· 1 oz centennial 45 min
· 1 oz centennial 30 min
· 1 oz centennial 15 min
· 1 oz cascade while cooling
· 1 oz cascade dry
· 1 oz centennial dry
· Wyeast 1056
Procedure:
Mash at 152F 90 minutes



Mash water quantity: 14.5 lb. grain X 1.25 quarts/lb. + 4.5 = ~22.5 quarts

Water to grain ratio: 22.5 / 14.5 = 1.55 quarts/lb.

Strike water temperature:
Tw = (.2/r)(T2-T1)+T2
Tw = (.2/1.55)(152-70)+152
Tw = .13 X 82 + 152
Tw = 162.5° F

2:50 Dough in. Worried about the temperature falling too low during the mash and let the strike water get up to about 166°, resulting in an initial mash temperature of about 156°. Began sparge after about 75 minutes with 170° water. I think we used too much water to sparge, as we ended up with perhaps a bit more than 8 gallons of wort before without fully draining the mash. Added about 8 gallons to the boil kettle and discarded a couple quarts or so of wort.

4:33 Begin boil

5:12 Hot break

6:17 Begin cooling

Cooled for about 30 minutes until the temperature fell to about 75°. Draining into fermenter provided ample aeration, judging from the thick layer of foam on the top. Original gravity: 1.050 at ~70° = 1.051.



OG: 1.050 at 70° = 1.051

The brewing session was catered by Robert, who provided a delicious, elegant seven course gourmet meal. Olives and green onions, baked brie encrusted in pastry, Caesar salad, mushrooms and parsnips, omelettes with smoked salmon and crème brûlée, a cheese course with four varieties, and fig flan. Wow! Beautiful and delicious.




Sunday, November 6

112 ppm, 64° at about 9:00 pm.