Beer has bacteria to thank for its intense, tart flavor. How does the beer-brewing fermentation process work, and what is the role of probiotics in our favorite drink?
We’ve already explored the magic of microbiology in kombucha and wine. If you’re not up to date on fermentation, just remember that some of these fizzy foods and drinks wouldn’t be possible without bacteria.
This week, we're getting curious about beer biology.
A beer-brewing renaissance
In recent years, a craft beer revival has taken hold of the US. Small, local breweries have sprung up in every neighborhood, all doing different and exciting things - and some quickly growing into larger operations. Here in Boston, we've seen a particularly significant change since the opening of the Sam Adams brewery. From mainstays like Sam and Harpoon to smaller operations like Jack's Abby and Mystic Brewery, Boston is a great place for beer nerds and novices alike.
The vital role of yeast
The brewers riding the wave of increased interest have an intimate relationship with the yeast, which plays an important role in the beer making process. Different yeasts are used for different beers: lagers and ales require their own yeasts, sour ales require a certain yeast strain, and some breweries (like Guiness) have secret yeast strains they've been brewing with for years. By mixing hot water and cracked, malted barley, brewers create a liquid called wort that acts as food for the yeast. The happy yeast eat the sugars in the wort and produce alcohol and CO2.
Some breweries (and most homebrewers) bottle condition their beer, allowing the remaining live yeast in the beer to continue fermentation in the bottle and create the fizz in your drink. Many breweries choose to cold-crash their beer instead, bringing the temperature of the liquid low enough that the yeast settles to the bottom. When brewers choose this method, they force carbonate the beer and add the bubbles themselves.
Bacteria in your bubbles
Regardless of how your beer is carbonated, that delicious flavor is made by the microscopic, probiotic multitaskers found in so many of our favorite foods.
A few common players in your favorite beer:
- Brettanomyces (“brett”): A type of yeast that slowly ferments the beer for intense, “funky” flavor.
- Lactobacillus (“lacto”): This bacteria devours sugar and produces lactic acid, lending beer a clean, smooth and sour taste. (It’s the same stuff in kimchi and yogurt!)
- Pediococcus (“pedio”): The pedio strain produces lactic acid and lowers pH, too. This taste is often described as the sharpest, with the most sour “bite.”
Taken together, each of these strains is to thank for that tart flavor we know and love.
The jury is still out on how good beer is for you, but we're willing to take the risk. We're ready to crack open a cold one -- just to make sure those bacteria are doing their job well ;)