Bottle fermented beer is yummy! Try some of the Belgian brews. It’s a secondary fermentation.
I think you’re crossing “bottle fermented” with “bottle conditioned”.
Bottle conditioned beer ferments the last bit to produce the carbonation in the bottle. This has the added benefit of consuming the oxygen in the air at the top of the bottle, which would otherwise start spoiling the beer. Once it has nothing left to ferment, the yeast falls out and forms the yeast ring (which we try not to pour with the beer, except for hefeweissen, for which we attempt to dislodge it first so that it
does get in the poured beer). While this is technically a secondary–or more likely tertiary–fermentation, it is not what we generally mean by the term.
Bottled home-brew is almost always bottle conditioned.
The primary fermentation of a beer lasts about three to seven days, in which many things fall out of solution. The beer is then drained from this to another fermenter for the secondary fermentation, largely to get it off of that crud. It is fully fermented before bottling. More crud falls out in the secondary.
For a bottle conditioned beer, either a bit of fresh unfermented beer from another batch, a bit of reserved wort (unfermented beer), or sugar is added to give the yeast something to ferment for carbonation.
If you actually tried the secondary fermentation in the bottle, rather than conditioning, there would be a serious risk of the bottle blowing from the released CO2. You would also have a bunch of red, rather than just yeast, at the bottom.
hawk
