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The Science of Craft Beer, in Ten Easy Steps

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Welcome to Craft Course, our column on the art of craft beer. Every week Christian DeBenedetti will take a look at interesting beer styles, brewmasters and their breweries, and more from high to low, East to West, and around the world.

[Photo: Christian DeBenedetti]

They say great wine is made in the vineyard, but how about beer? The process, for the uninitiated, is both surprisingly complex and beautifully simple, an alchemical tango between quality natural ingredients and precise operations in the brewhouse. Working with the basic ingredients of malted barley (or sometimes wheat or other grains), fragrant hop flowers (in various forms), yeast, and water, brewers conjure an amazing array of flavors in over 130 recognizable styles.

We recently visited Denver, Colorado's Great Divide Brewery for a crash course in the art and science of brewing craft beers. The process varies by style from place to place, but here, for your edification, are the basic ten steps to make a craft beer.

Barley Malt [Photo: Christian DeBenedetti]

1. The vast majority of beers are made with a base of malted barley, which is grain that has been dampened, allowed to sprout, carefully dried and sometimes roasted (imparting color and texture to beers). Additionally, grains such as rye (as with Hoss Rye Lager, the beer we're looking at today), wheat, and rice may also be used in conjunction with malted barley to make up the base malt. The malting process creates enzymes, which will later convert the starches already present in barley into sugars during the mashing process.

The Grain Mill [Photo: Christian DeBenedetti]

First the brewer mills the grain to crack the kernels' husks so the starches inside will be more accessible to enzymes during the mashing process. A standard batch requires 3,500-4,000 (Hoss has 3,700lbs) pounds of grain.

The Mash Tun [Photo: Christian DeBenedetti]

2. Next the grain is transferred into the mash tun with around 1,090 gallons of water at a temperature from 148 - 157 degrees. Every brewery uses a different mashing technique, adjusting the temperatures and mash times, but generally this is about a one-hour process. The liquid must have time to rest, during which time the enzymes created during the malting process convert the starches present into simple sugars, which will later be fermented.

The resulting mixture is called wort, and it's deliciously sweet and healthful. Some brewers make a point to drink a glass on their morning shift. Brewers also monitor their water very carefully: hardness and softness of water affect the brewing process and resulting flavors.

Hops [Photo: Christian DeBenedetti]

3. Next is the all important kettle/whirpool stage. After a two-hour transfer of the wort into this tank, the brewer adds a first addition of German hops (for Hoss, this is 14 lbs. Bigger beers, like Great Divide's Hercules Double IPA, has an initial addition of 40lbs) and brings the mixture to a rolling boil for around an hour. Hops are a resinous plant in the same family as the stinging nettle (and cannabis!), and they give beer its bitterness and aromas, thanks to something called lupulin, which resides in pollen-like glands inside the base of the flowers.

The Kettle/Whirlpool [Photo: Christian DeBenedetti]

There are dozens of hop varieties, and brewers choose among them depending on their flavor and aroma profiles, which can range from piney to citrusy, grapefruity, grassy, dank, and herbal. They can be added in whole flower form, condensed into pellets (as shown), or added as an oily extract (more of an industrial timesaver). They balance the sweetness of malt and enhance the stability of beer. Depending on when they are added, they can give the beer bitterness (early addition) or aroma (later additions). At the end of this stage, the brewer uses a whirpool function to siphon out the used hops.

Stainless Steel Tanks for Fermentation [Photo: Christian DeBenedetti]

4. When the beer has cooled, the wort is transferred to huge stainless steel tanks for fermentation. Brewers' yeast is added for this stage, which immediately begin to feast on the sugar-rich brew, creating the byproducts of alcohol, CO2, and heat. There are two different main strains of brewers' yeasts: Saccharomyces cerevisiae, which works at warmer temperatures creating ales, and Saccharomyces uvarum, which works at lower temperatures, for lager beers.

The beer will stay here for seven to ten days, and then the temperature is dropped to 32F for a period of seven days to two months, reaching anywhere from 5-12% alcohol by volume; Hoss is a 6.2% beer. For this beer, Great Divide brewers utilize a lager yeast and then drop the temperature to 32F for five weeks, to condition the brew.

Wooden Barrels [Photo: Christian DeBenedetti]

5. Some of Great Divide's beers are aged in wooden barrels that once contained Stranahan's Colorado Whisky. Barrel aging is tricky, but when properly executed, it gives beer a great deal of character, both from the barrel type used and special yeasts that are sometimes added during this stage, imparting oak, char, and other earthy and sour flavors. (Note: Hoss Rye Lager, the beer I'll later try, isn't barrel-aged.)

The Filter [Photo: Christian DeBenedetti]

6. Next the beers are pumped through a filter made of diatomaceous earth (DE for short), a highly porous, silica-rich powder made from millions of fossilized diatoms, a sort of ancient algae. The filter removes spent yeast cells, grain matter, and other impurities the brewer doesn't want in the beer. Later the DE refuse and spent grains from the mash tun are mixed and sent to a local farmer as cattle feed.

The Brite Beer Tank [Photo: Christian DeBenedetti]

7. Here in the brite beer tank the beer rests for one day, and is force-carbonated with C02 at around 15 PSI. Each tank has a capacity of 100 brewers' barrels (BBL), or about 3,100 gallons (as do the fermenters).

The Bottling Line [Photo: Christian DeBenedetti]

8. Now clear, fully fermented, carbonated, and rested, the beer is packaged in bottles or kegs. This bottling line can fill and cap at a rate of 140btls per minute.

The Brewery [Photo: Christian DeBenedetti]

9. Great Divide was built in a former dairy processing plant.

The Tap Room [Photo: Christian DeBenedetti]

The attached taproom is a busy spot for locals at almost any time of day.

The Drink [Photo: Christian DeBenedetti]

10. Pröst! The fermentation and aging process takes weeks, so in the meantime I go for a freshly-kegged pint of Hoss Rye Lager, a crisp, spicy lager brewed as a riff on the traditional German Märzen, utilizing rye in addition to barley. It's incredibly technical to make, but an delicious, natural pleasure to drink.

Oregon native Christian DeBenedetti (@debenedetti) is currently hard at work writing a book about American craft beer for National Geographic, due out in the Fall of 2011, and writes about beer and travel for magazines including Food & Wine, Men's Journal, Departures, Outside, and others. He lives and drinks in his hometown, Portland.

· Great Divide Brewery [Official Site]
· Oktoberfest Celebrates 200 Years of Ruining German Livers [-E-]
· All Craft Course Posts on Eater [-E-]
· All Beer Coverage on Eater [-E-]

Great Divide Brewery

2201 Arapahoe Street, Denver, CO‎

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