ESB - the fermenter is bubbling!

I have to admit that I was a little worried that the yeast might not have been alive enough to work. The night I bought the ingredients in Bethlehem, I left them overnight in the car (no fridge in the room). If the yeast had frozen, game over. However, the packaging claims 100 billion active cells, so I guess enough of them lived. It took about 5-6 hours, but now the fermenter is happily bubbling away at 75 deg F.

Time to define some terms that I glossed over last night:

Hot break: proteins that clump up and precipitate out of solution during the boil (that foaming the first time the wort comes to a boil)
Cold break: proteins that clump up and precipitate out of solution when the wort is rapidly cooled.

Besides being milestones (i.e. they are supposed to happen), these breaks are the outward signs of chemical changes that are good for the brew. Part of the reason you boil the brew uncovered is to allow this escape of sulfur compounds released in the boil. These compounds (dimethyl sulfides) can lead to off-flavors like cabbage or eggs. The hot break is an indication that some of the bad stuff is boiling out of your beer-to-be.

The cold break is the result of the thermal shock of rapidly cooling the wort from 212 degF to below 80. Slow cooling will not cause the same phenomenon. If the proteins remain in solution, this can lead to "chill haze," (fog when you chill bottled beer). No affect on the flavor, but the cold-break proteins continued presence in solution means the beer may go stale more quickly.

Observing break formation is a good sign because these proteins will eventually settle out of the solution before you bottle, giving a clearer beer.