The Curious Case of Butterbeer: A Brewing Mystery

For all the beer connoisseurs out there, the concept of “butterbeer” may not be as fictional as it seems. Sure, we’ve all encountered those licensed novelty drinks at theme parks, but every now and then, you might stumble upon a beer that has a faint taste of buttered popcorn, even when it’s fresh from the tap or bottle. Intriguing, isn’t it? But how does this buttery flavor find its way into the beer in the first place? Well, let’s delve into the fascinating and somewhat surprising world of diacetyl.

Diacetyl, an alpha-diketone, is a chemical compound produced during the beer manufacturing process. It is commonly used as an artificial flavoring due to its strong buttery aroma. You might recognize its taste from microwave popcorn, movie theater popcorn, and some artificially flavored coffees. Surprisingly, diacetyl is also found in e-cigarettes and is even used to enhance the buttery taste in margarine, butter, and oil sprays. You might be surprised to learn that even real butter itself contains low levels of diacetyl.

Now here’s the interesting part: diacetyl is a natural byproduct of yeast fermentation. So, most beers produced with yeast will have some level of diacetyl during the brewing process. However, brewers usually have methods to control and eliminate diacetyl before the beer is ready for sale. If you detect that unmistakable buttery taste in your beer, it could mean that the diacetyl was intentionally left in for flavor, or there might have been sanitation issues during production.

As intriguing as butter-flavored beer may sound, it’s important to note that a hint of butter in your brew is far from harmless. Prolonged exposure to high levels of diacetyl is known to cause bronchiolitis obliterans, a severe and often fatal lung condition commonly referred to as “popcorn lung.” This condition initially came to light when it was discovered among microwave popcorn factory workers (via the American Lung Association). Even though the low levels of diacetyl found in beer and flavored foods were generally considered safe, recent studies suggest that even minimal exposure to diacetyl from consuming flavored foods can increase your susceptibility to COVID-19. Needless to say, it’s not something you want to find in your beer.

If you’re a novice home brewer, it’s crucial to understand how to control diacetyl in your creations. First and foremost, pay utmost attention to sanitation. While diacetyl is a natural byproduct of fermentation, it can also result from unwanted bacteria. Ensuring proper sanitation of your equipment and bottles will help mitigate the diacetyl issue and prevent any other potential contamination problems. Additionally, creating the right conditions for yeast to naturally reabsorb diacetyl during fermentation is key. This involves increasing the temperature towards the end of fermentation to enhance yeast metabolism, followed by cooling it down and allowing the yeast to rest in the bottles for a week before removing them. Furthermore, it’s essential to keep the beer cold after bottling to avoid any further re-fermentation of diacetyl during storage.

In conclusion, while the concept of butterbeer may have originated from the realms of fiction, there is indeed a scientific basis behind its flavor. Diacetyl, a chemical compound produced during the beer manufacturing process, lends that familiar buttery taste to certain brews. However, it’s crucial to ensure that diacetyl is controlled and kept at safe levels. As enjoyable as a hint of butter may be in your beer, it’s important to prioritize your health and make informed choices when it comes to consuming beverages with diacetyl.

Source: Tasting Table