The Mudcat Café TM
Thread #77153   Message #1373642
Posted By: Gurney
07-Jan-05 - 12:52 AM
Thread Name: BS: Unpasteurized beer
Subject: RE: BS: Unpasteurized beer
Jim Dixon, I brew my own sometimes, and this is what I understand the case to be.
Yeast brews until the alcohol content renders it inactive or dead. This point is reached at between 7 and 10 percent with most yeasts, and the sugar content of the brew supports that alcohol level.
Some yeasts are tougher and will live up to 12% and are used for strong ales like Newcastle Brown. Champagne yeast is used for 'double brewing' where the beer is resugared and rebrewed to make a very strong ale like Barley Wine.

We all have tales about bottles exploding, but this usually happens when the yeast stops working for some reason,-like cold weather,- and the brewer bottles the beer thinking it is brewed out. When bottled the beer is given a little more sugar so that the product has life/fizz/head/Co2. If it isn't brewed out, there is too much sugar in the bottle, which will turn into alcohol, giving off Co2 in the process. It is this excess Co2 which bursts the bottle. I would think it unlikely any commercially brewed product would explode, but accidents do happen.
As a matter of interest, alcohol has a higher expansion rate than water, so that is why there has to be a space in alcohol bottles.
A contract bottler I worked for overfilled toilet water bottles once, and I had '4711' all over my store...smelled like Granny's sideboard.