NORMAL - Matt Potts had already dumped calcium sulphate and calcium carbonate into the massive metallic cauldron in front of him. | Video: How beer is made | Photo gallery | Interested in brewing beer at home? | Benefit planned for family of Destihl partner

Now, his eyes were glued to an equally large control panel 10 feet away, slowly inching up the temperature inside the cauldron to help enzymes get to work on the mishmash of grains and chemically altered water he's put in there.

Nearby, his assistant and strict record-keeper, Keith Gabbett, was documenting each temperature change so they knew where they stood if something happened to go wrong.

Making beer has never sounded so fun.

Potts, 39, is CEO and brewmaster at the five-month-old Destihl Restaurant and Brew Works, 318 S. Towanda Ave. Gabbett is the assistant brewmaster in Destihl's multi-level brewery.

They wear black polo shirts instead of white lab coats. But they are scientists of sorts, spending at least two days a week playing with chemical reactions, single-cell organisms, heavy-duty machinery and, well, alcohol.

"There's a lot of science in it … but you can make it as fun as you want it to be," Gabbett said.

As craft brewers - defined as a traditional, small-scale brewer largely owned by the people making the beer - Potts and Gabbett are in a growth industry. Home brewing caught on in the U.S. in the 1960s and '70s, with craft brewing developed by its pioneers in the '80s.

And since 1978, the U.S. craft brewing industry has never lost market share, according to the not-for-profit Brewers Association.

So, with a decent hold on the market and more beer drinkers willing to try something new, it's time to experiment, so to speak. And that's a far cry from old-school Germany, which still has a centuries-old beer purity law on the books that essentially limits ingredients to the basic four: water, grain, yeast and hops.

A look at Destihl's beer menu, for example, will show some exotic tastes: beer that's been stored inside a bourbon-coated barrel for months; an oatmeal stout that's had coffee beans steeped in; and a beer due out in August that's been sitting in an old red wine barrel with pounds of mashed fruit since March.

The emergence of craft breweries - where trade secrets are few and far between, Potts said - coincides with a growing list of beer styles, which the Brewers Association tracks in its annual beer-styles guidelines. It's a veritable periodic table of elements for beer scientists, with hundreds of categories. In 2008, the association added several wood or barrel-aged categories, like Destihl has on tap.

"You may not like every single beer (that Destihl makes), but there's gonna be several there that are in your preferred flavor profile, that you're gonna like," Potts said.

The scientific process

There seems to be at every step in the beer-making process room to diverge even further from that old German beer purity law.

On one 12-hour-plus brew session last month, Potts and Gabbett started a new, 250-gallon batch (17 kegs) of their Jivaro Oatmeal Espresso Stout. Before they put malted barley and oats into the big cauldron of water - beer's biggest ingredient - Potts used some calcium sulphate (gypsum) and calcium carbonate (chalk) to make the water "harder," matching the stout's English origins by mimicking the taste of London's drinking water.

Grain amounts are the primary factor in a brew's alcohol content after fermentation. For this stout, about 450 pounds of grain (barley and oats) makes its alcohol-by-volume level higher than most at Destihl.

Instead of mashing together just barley and water, Potts and Gabbett also add oats. The temperature inside the mash kettle is then raised as enzymes start breaking down the grains into sugars. That sugary mash is sent through pipes to the "lauter tun," another large metal tank, which extracts sugar water (or "wort") from the grains in a process that takes hours if done right. The wort is sent back to the mash kettle, which has been cleaned out and had its name changed to the "brew kettle."

But that's where it gets fun again. Once the wort is brought to a boil, different types of hops - little heavily scented pellets that add bitterness, citrus or fruity flavors - are added.

But in a business where timing is everything, Potts will lose some of the power of the bittering and flavor hops if he leaves them in the boil too long. And because he doesn't want the stout to be too bitter, he "underhops" it, measuring levels on the International Bitterness Units scale.

When the boil's done, he steeps six pounds of bagged South American and African espresso beans in the kettle, just enough to give it a coffee tinge at the tap.

"It's not really in your face. It's a little more subtle," Potts said.

The concoction is then sent to a whirlpool, which separates some unwanted chunky leftovers from the good stuff, and a chiller, which brings everything down to a cooler desired fermentation temperature. Once it arrives in one of Destihl's four fermenters, yeast, the stinky single-cell organism, is added, and begins eating up the sugars in the liquid and kicks out carbon dioxide and alcohol.

With a two-week fermentation time, the espresso stout - because it's an ale - will be drinkable about two weeks after brewing began. Fermentation for Destihl's few lagers, such as the Normal Lager (an attempt to match a Budweiser, for example), typically takes several weeks longer.

But the tweaking doesn't have to stop there.

On that same Thursday last month, the guys were also moving a new brew, a framboise, from a fermenter to a red-wine-coated barrel, where it'll sit on top of 80 pounds of mashed raspberries and 25 pounds of mashed sour cherries. With some yeast added, fermentation will continue in that barrel until August, when Potts wants to tap the beer in time for his wife's birthday.

"My wife doesn't really drink much beer. Imagine that, married to the brewmaster, doesn't drink much beer," he said. "But she likes this."

Life in the brewery

Despite all the number-crunching and clock-watching, Potts and Gabbett keep things appropriately light in the brewery. They are making beer, after all.

With parts of the process taking hours at a time, like the lautering, there is plenty of down time, which they fill by cleaning out old kegs or working on more than one brew each day.

"There are periods of very light activity followed by periods of very heavy activity," said Gabbett, who drives down from the Chicago area for Destihl's two weekly brewing sessions. "Of course, when something goes wrong, there are periods of very heavy activity."

On this particular Thursday, that was when some equipment came loose during a transfer and sent beer spraying into the air like a geyser for a few seconds. Potts and Gabbett spent about 10 minutes disinfecting the entire area, as yeast can contaminate anything it touches.

What do they call it when something like that happens?

"Bad," Potts joked.

"Yeah, that's bad," Gabbett added.

Staying grounded is easy, too, as Destihl's stainless-steel brewery is visible to patrons through glass behind the restaurant's bar area. "It's really cool to look out at people in the bar drinking something that you made," said Gabbett, who met Potts while they were training at the Siebel Institute of Technology & World Brewing Academy in Chicago.

Even with all the tweaking craft breweries do to their beers, Gabbett still marvels at the nearly infinite range of colors, tastes, aromas, bitterness levels, etc., that can be achieved with essentially four basic ingredients.

"There are so many possibilities and so many variations that you can't really get bored with it," he said.

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Need a drink?

Here are some downstate breweries within reasonable driving distance:

• Illinois Brewing Co., 102 N. Center St., downtown Bloomington. Known for its homegrown brews, live music on the weekends and proximity to the U.S. Cellular Coliseum. (309) 829-2805; www.myspace.com/illinoisbrewing

• Destihl Restaurant and Brew Works, 318 S. Towanda Ave., Normal. Serves only its own beers, of which it has plenty, to complement its "urban American" menu. Located on west side of Shoppes of College Hills, with another location set to open in Champaign in early 2009. (309) 862-2337; www.destihl.com

• Granite City Food & Brewery, 230 Conference Center Drive, East Peoria. This Midwest chain of restaurants/breweries, with three Illinois locations, has plenty of sandwiches on the menu for less than $10; fancier fare lands between $11 and $22. (309) 669-8080; www.gcfb.com

• John S. Rhodell Brewery, 619 SW Water St., Peoria. Rhodell - which warns "Caution: Our beers have flavor" - has a brewer who creates more than 30 different styles throughout the year for its bar. (309) 674-7267; www.rhodellbrewery.com

SOURCES: Brewing Association, the breweries' Web sites

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From A to Beer

A step-by-step look at how Destihl makes its Jivaro Oatmeal Espresso Stout:

Early morning to 8:30 a.m.: Recipe is double-checked. Barley is milled, or cracked open, and brought in bags to the kettle, where it'll be mashed together with oats and water.

8:30 a.m.: Before mash begins, water (from the town of Normal) in the mash kettle is adjusted using calcium sulphate (gypsum) and calcium carbonate (chalk) to match it to London water and the stout's English origins.

8:50 a.m.: About 450 pounds of grain are added to the water for a 250-gallon batch. The more grains that are added, the higher the beer's alcohol content. Then, temperature changes trigger enzymes that break down the grains into sugars.

10:40 a.m.: The mash is sent to the lauter tun, a large metal tank, where for the next several hours sugars will be pulled from the spent grains to create sugar water, or wort, and drained through the bottom. Water is later sprayed, or "sparged," onto the mash inside the lauter to extract any remaining sugars before the wort is sent back to the cleaned-out kettle. Rushing this process will create a vacuum at the bottom of the lauter tun, which will eventually slow the brewing.

5:30 p.m.: Once enough wort is back in the kettle and at a boil, bittering hops are added. At 6:45 p.m., flavor hops are added. If the hops are left in too long, some of the flavor will be lost in the steam.

7:30 p.m.: The brewers finish steeping, or soaking, bags of South American and African coffee beans in the wort, giving the brew the "espresso" part of its name.

8:15 p.m.: The wort ends up in one of Destihl's four fermenters - where it'll stay for two weeks - after going through the whirlpool and a chiller. The whirlpool separates the good wort from some unwanted leftovers (namely coagulated protein) and sends it to the chiller, which brings the wort down to target fermentation temperatures.

8:45 p.m.: Cleanup is completed. During the two weeks of fermentation, the yeast will consume the fermentable sugars in the wort, producing carbon dioxide and - finally - alcohol. Then, the stout will be transferred to a large tank, where it can be served.

SOURCES: Matt Potts and Keith Gabbett, Destihl Restaurant and Brew Works