My wife and I share a house that occupies all of 900 square feet. Throw in two cats, who somehow manage to occupy far more volume than their combined eighteen pounds of fur really ought to, and one becomes a master of creatively multi-purposing available space. So, our second bedroom doubles as my home office and triples as what Belgian brewers call a warm room—a space to store bottles of beer as they naturally carbonate.
In autumn 2011, three weeks after bottling five gallons of saison, I needed to reconfigure the warm room as a bedroom for out-of-town guests. But instead of moving fifty-five bottles of perfectly carbonated farmhouse ale to cold storage, I instead found myself picking up shards of glass and befriending the gentleman from whom I rented a wet vac.
Almost every homebrewer encounters the dreaded “bottle bomb” at some point. Here’s why it happens.
- Incomplete fermentation: This is what led to the demise of my beloved saison. I thought my beer had reached terminal gravity. The Dupont yeast strain begged to differ.
- Too much priming sugar: Most standard beer bottles can safely handle no more than about 3 volumes of carbon dioxide. Priming with too much sugar can easily put you over the limit.
- Inconsistent priming: If you don’t thoroughly mix the priming sugar with your fermented beer, some bottles may fall flat while others explode with effervescence.
- Contamination: Wild yeast and bacteria ferment certain sugars that normal brewers yeast can’t. If your beer becomes contaminated with an uninvited organism, over-carbonation may result.
- Heat: Carbon dioxide obeys basic physics. As temperature increases, so does pressure. Furthermore, warm beer holds less CO2 than cold beer, so the small headspace in the bottle’s neck becomes even more pressurized.