My fermenter has overflowed the airlock. Is the batch bad?
Probably not. This is due to an extremely active ferment, and is more common with higher gravity ales in warmer weather. This overflowing will last for 8 to 20 hours, and then subside. Clean up the airlock and replace it on the fermenter. It may become clogged again, depending on how long before the overflowing subsides. There is usually not a great danger of bacterial infection during this vigorous period, because fermentation produced C02 is being rapidly generated, shielding the beer from bacterial contamination. Carbon dioxide (C02) is heavier than air, and forms a blanket over the fermenting wort. Bacteria will suffocate in a C02 environment. In the future, to avoid this situation, place the fermenter in a cooler area, or you might try switching to a glass carboy with 4′ of 1″ interior diameter blow off tubing attached.
