Fill Level Experiment

by Al Korzonas

Reprinted from HomeBrewers

Digest # 1991 with permission

Al Korzonas is a BJCP Master Judge who has been brewing since 1987.

He is the owner of Sheaf & Vine Brewing Supply in Countryside, Illinois, a technical editor for Zymurgy and is the author of "Brewing Made Easy" scheduled to be published by Storey Communications in Fall 1996.

Back in January, we had a discussion regarding the effect of fill level on carbonation for batch-primed beers. Last night I tasted the results of my experiment. The beer was an all-grain American Pale Ale and was primed with 2/3 cup of corn sugar for the 4.5 gallons in the priming carboy. I filled bottles at four different levels:

HIGH: 1.6 cm headspace

NORMAL: 4.7 cm headspace

LOW: 6.6 cm headspace

VERY LOW: 8.7 cm headspace

I had my wife Karen randomly assign numbers to the bottles and the glasses were labeled only with numbers. I was in the basement while she poured, so I could not hear the difference in "fffffft." She poured the same amount in all four glasses, down the side, in exactly the same way. The glases were all beer-clean and at the same temperature. The beers were all at 55 °F.

The beer had been bottled on 1/26/96 and this test was done on 3/18/96. The bottles were conditioning in a dark room that was between 64 and 67 °F.

Here are my results:

The HIGH fill beer had very slightly less carbonation than the rest.

All the rest of the beers had no perceptable difference in carbonation.