Bottling Number VIII

With Jean the bottling begins. Primer was 400ml light spray malt in a litre of water, boiled and cooled.

Final tasting notes show a beer with some esther characteristics but light and a little bitterness. The flavour is interesting,though it's still relatively early. Bottling went well following the same procedure as VII, giving about 55 bottles.

FG is 1024@17C
SG was 1056@20C

Hydrometer must be read at 20C, and to the lowest level of the meniscus.
Correction for other temperatures to hydrometer reading is 0.002 to 0.003 per 10C, temperature too high will give a reading too low, temperature too low will give a reading too high.

For this calculation:
Correct 1024@17C to 1023@20C

1.056 - 1.023 = 0.033 * 105 = 3.5
This, I think, is % by weight, not % by volume, or something and needs another correction.

Ah, found here: http://www.realbeer.com/library/beerbreak/archives/beerbreak0301.php
Alcohol percentage by weight equals 76.08 times Original Gravity minus Final Gravity divided by 1.775 minus Original Gravity. It is easier to scribble this down: ABW = 76.08(OG-FG)/(1.775-OG).

You should remember that ABW is used mostly in the United States, while the rest of the beer world (as well as the wine and spirits world) measures Alcohol by Volume (ABV). That conversion is easy: ABV = ABW (FG/.794).

So:
ABW = 76.08(OG-FG)/(1.775-OG)

ABW = 76.08( 1.056 - 1.023 ) / ( 1.775 - 1.056 )
= 3.5

ABV = ABW (FG/.794)
= 3.5 * (1.023 / 0.794 )
= 4.5%