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We begin our brewing journey with the humble grain. At the north end of our brewery, you’ll find our mill room with our state-of-the-art wet mill. Grain passes through our malting station to remove debris and grain husks. The grain then travels to our wet mill where we gently open the two-row malted barley kernels. Each of these kernels contains long chain sugars and the enzymes that simplify them into short chain sugars.
The first stop in our brewhouse is the mash tun on the north-most side of our brew deck. Here we combine the malt with hot water. This encourages enzymes in the malt to convert starches into simple sugars that can be fermented. This process creates wort - a hot, sweet liquid. We introduce water at 145-160 degrees Fahrenheit. A lower mash temperature will yield a drier beer and a higher one will yield a sweeter beer with more body.
The wort continues on to the lauter. This is the largest vessel on our brew deck. We separate the wort from the grain by adding water, recirculating the wort, and extracting fermentable sugars. The wort flows through the grain bed along the bottom of this vessel for one to two hours, which clarifies the wort before it goes to the kettle.
The kettle is where we add hops, denature proteins, burn off undesirable off-flavors, and reduce the wort. Hops are typically added in three additions. The first addition acts as the bittering hop, creating most of the IBUs (International Bitterness Units). The second addition is added for hop flavor, and the third addition goes in when the boil is complete to enhance the aromatics of the beer.
We pump the wort through our hop dosing vessels for the bittering hop addition and the flavor hop addition, then send it back to the kettle. Our beers and palates demand a whole lotta hops, but we have limited space in our kettle, so we reduce the vegetative matter created by the hops. At this stage, we also add adjuncts like the orange peel and coriander that go into White Rascal.
The last vessel on the brew deck is the whirlpool. We pump the filtered hot wort at an angle onto the wall of the vessel. This creates a “whirlpool” that naturally collects the stuff we don’t want in our beer, like hop detritus, proteinaceous matter, and undesirable malt byproducts. What comes out of the whirlpool is hot, clarified, perfect wort.
We take “weak wort” (wort too low in sugar content to be viable for fermentation) and send it to the City of Boulder’s WasteWater Treatment Plant. They use our weak wort to feed the bugs that clarify some of the city's gray water. It’s a symbiotic and cool relationship with our community that also reduces waste!
We dry hop in a closed system that lets us introduce our dry hops via a hop cannon. This provides our hoppiest beers with more hop aroma while reducing the risk of oxidation and infection.
We grow our beloved yeast strains up from a single cell in our cryogenic yeast bank. Yeast are efficient little organisms that love fermentation: the process of converting wort to alcohol and CO2, along with flavor and aroma compounds. Our brewers tweak the environments of our five yeast strains to produce different levels of flavor and aroma compounds, as well as varying alcohol levels.
Our yeast prop system consists of a two phase process. First, we pitch yeast from our yeast supplier into a tank of wort with 50% headspace. After 48 hours of initial fermentation, this yeast slurry is ready to move to the second phase, where the growing process continues in a bigger tank.
Wort moves from our whirlpool, cools over the heat exchanger, and travels in a closed system to be dosed with yeast. So begins fermentation, turning wort into beer! The yeast eats the sugars in the wort and produces three by-products: alcohol, CO2, and heat.
We have 27 fermentation tanks that range in size from 120 barrels to 720 barrels. Our beers take between 6 and 28 days to ferment, depending on the yeast and alcohol content. After fermentation is complete, we dry-hop some beers for even more hop aroma.
Finally, we run our beers through a centrifuge. This machine spins the beer at 4,850 RPM, giving our beers both clarity and brilliance or haziness and opacity depending on the style. “Spinning” the beer increases shelf stability, especially for beers that have been dry-hopped.
At the end of our journey, our beer heads to a bright tank where it is chilled and carbonated. Now our beer is ready to be canned, bottled, or kegged! Below you is the wonderful and noisy world of packaging. Our keg line fills 50 kegs/hour, our bottling line fills 110 12-oz bottles/minute, and our canning line fills 220 cans a minute. Several final quality checks are done during the packaging process. We x-ray each can seam to make sure each beer is completely sealed, we test how much dissolved oxygen is in the packaged beer, and we pull samples.
We began experimenting with barrel–aging in 2003 and we bottled our first barrel-aged beer in 2009. We design sour and non–sour beers from scratch to marry flavors with a variety of oak barrels. Our barrel–aging department continues to be the most experimental arm of the brewery, and there are now more than 60 beers in our Barrel–Aged Series, including beers aged in barrels that housed red wine, white wine, Bourbon, whiskey, tequila, rum, Madeira, Port, and Carcavelos.
We transfer pallets of cans, bottles, and kegs to our 40°F warehouse. Our warehouse doesn’t have windows and the doors automatically open and close as forklifts to pass through so that we can keep light away from our beer. We ship our beer on 40°F refrigerated trucks and include temperature recording devices to ensure that our beer stays at a constant temperature as it travels to our distributors around the country. From there, our beer journeys to liquor stores, restaurants, and bars before it's finally delivered to your mouth.