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The Science of Brewing Beer

Beer isn’t just a favorite way to wash down a plate of game-night chicken wings. It’s been a part of the human experience for at least 7,000 years. In many different forms, it swept through the ancient civilizations of Egypt and China, through Europe, and onto the tables of our founding fathers to become America’s favorite alcoholic beverage.

While the basic process of making beer has been very much the same throughout the years, our understanding of how that process works is relatively new. There’s more going on under the surface of a new batch of beer than its ancient inventors ever imagined.

“Fermentation is my favorite part of the process,” says Mike Brandt, Owner and Brewmaster at Garden Grove Brewing and Urban Winery in Richmond. “The different strains of yeast have distinct personalities and can produce all kinds of flavors—really unpleasant ones or really great ones.”

Experimenting with fermentation gave Brandt more than just new brews to try.

“It taught me that I like microbiology,” he says. “I wouldn’t have thought that was an interesting field until I started making beer.”

Brandt’s brewmastery began with a gift from the woman who is now his wife: a simple home brew kit. Instead of ending up on a shelf in the garage, as many home brew kits do, it sparked an obsession for him.

What is the secret to making that home brew kit a productive pleasure instead of forgotten clutter?

“Clean, clean, clean,” says Brandt. “Probably 70 to 80 percent of a good brew is cleaning. If you don’t do a good job of that, you can introduce unwanted microbes to the process and ruin the whole thing.”

Want to know more about the beer brewing process? Check out this video produced by PBS Digital Studios.

More Science of the Beer Brewing Process:
The first step in the process is malting. This is where barley (a grain, much like wheat) is soaked in water to soften it, then spread out to begin germinating. During germination, the plant releases enzymes called protease and amylase, which change its starchy nutrients into sugars and peptides. The grains are then baked at a low temperature to produce malt.

The malt is then milled (cracked open) and mashed (dissolved and mixed into water), producing a sugary fluid called wort. This is boiled and then hops (the green flowers of a hop plant) are added for flavor—they have a bitter, citrusy quality that helps balance out all the sugar. The hops bond with the peptides and proteins to sterilize the mixture and stabilize its foamy texture. The hops are then filtered out, and the whole mixture is cooled to prepare for the next step.

Next comes fermentation, which gives the beer its bubbles and alcohol content. Yeast is added, and over several days it converts the sugars to carbon dioxide and ethanol and other substances that give beers additional flavors. Yeast is a single-celled microorganism, and there are hundreds of different species to choose from. Most fermentations are done with one of two main species of yeast:  "normal" brewer's yeast, saccharomyces cerevisiae, or "lager" yeast, saccharomyces pastorianus. Each of these yeasts require a different fermentation temperature to work properly -- the regular yeast (s. cervisiae) ferments best from 65-70 deg. F, typically, but can sometimes be used with fermentation temperatures as high as 85-90 degrees. All of these methods are forms of "warm fermentation." Lager yeast (s. pastorianus) is fermented at a lower temperature (i.e., "cold fermentation"), c. 50 deg. F or so. And, as the name suggests, lager beers are made with this yeast.

Bacteria, such as pediococcus and lactobacillus, may also be added to lend a tart flavor to the mixture. All of these microorganisms multiply very rapidly, mutating as they go, which can introduce new flavors to the process over time.

The beer is then stored for a period of time which is called “conditioning” or “aging” allowing the flavors to mix and mellow out. This process can take anywhere from a couple of weeks to several years, depending on the kind of beer being made.

Some beers are “clarified” at the end of their processing. In this step, a clarifying agent is added to the beer to remove proteins and other substances that cloud the beer. Traditionally, this was done with a swim bladder from fish, called isenglass, but nowadays, this can be done with certain kinds of seaweed or with an artificial clarifier called polycar.

Lastly, the beer is filtered to remove any remaining solids and then bottled, canned or kegged for sale and ready to enjoy.

 

Article by: Lia Tremblay


For a limited time try Ale Things Considered at Garden Grove Brewing and Urban Winery. A dollar from each pint supports the Community Idea Station's mission to educate, entertain and inspire. The collaboration also features a special ingredient found on the Slow Foods Ark of Taste list called the Hog Island Fig. Learn more about the endangered fig from a recent Virginia Currents report The Hog Island Fig: Saving A Tree To Preserve Virginia Barrier Island History. A special thanks to those who helped the beer and story come to life including John Haddad, Bernie Herman, Bill Neil, Tom Gallivan, Mike Brandt (pictured above), Chris Sarnoski, Ryan Mitchell, Laura Vaughan, Sally Dickinson and the Barrier Island Center.