Many of us have had them—beers that didn’t taste quite right. Maybe it was notes of tart cherries, or a touch of movie-theater buttered popcorn, or an exuberant carbonation that overflowed the glass that raised questions in our minds as to whether this was the way we should be experiencing the beer. But something just wasn’t right.
The bad news for beer fans everywhere is that the things that turn good beer to bad—bacteria such as Lactobacillus and Pediococcus, wild Saccharomyces yeast strains, funky Brettanomyces yeast, and similar microbes—are absolutely everywhere in our human environment. Scientists estimate that within our bodies alone, about 100 trillion microbes—bacteria, yeast, viruses, etc.—live and thrive. Many provide beneficial effects, as Lactobacillus in particular is an important part of the gut biome and aids in digestion. But those same bacteria are also highly efficient at consuming the sugars within beer and converting them into flavors that brewers either embrace (in the case of sour and wild beer) or despise (in every other style of beer).
Given the incredible number of these microbes in our general environment, brewers everywhere work hard to control and corral them with cleaning and sanitizing processes designed to knock down their numbers. Once yeast produces alcohol, the environment within beer becomes even less hospitable for potential spoilers. Yet still, some slip through in large enough quantities to establish a foothold. Let’s dig into why and how some of these spoilers are able to evade even some of the most aggressive sanitation and testing regimens in the industry.