How We Brew
Quality is a journey. Here's our map.
Four Key Ingredients
We start with these.
The places where beer styles emerged earned their reputation for that style in great part because of their water. Today, we can manipulate the chemistry of water to mimic that of those famous spots, and intentionally achieve flavor varieties that brewers of yore would think impossible.
The primary sugar source for beer. While any starch-rich grain can be used (wheat, rye, sorghum, etc.), the vast majority of grain used for brewing is barley. In order to make those starches accessible as a food source for yeast, barley is first malted. Malting is a process of wetting then quick-drying harvested grain to make the seed think it’s time to grow. After malting, enzymes are accessible to allow the conversion of starches into sugars. The malt is then kilned, or roasted, which adds color and flavor to the beer. The longer the malt is toasted, the darker the grains will become and the more complex flavors will be produced. Flavors of toast, caramel, chocolate, and coffee are some that can be created as the malt gets darker with more time kilning.
This flower produces an aromatic yellow resin from its lupulin glands that is loaded with Alpha and Beta acids, which are the components responsible for bittering beer and balancing the sweetness of malt. There are dozens of hop varieties, which produce flavors and scents like citrus, pine, earthiness, grass, and many more. As soon as hops are picked from the vine, these aromas and flavors begin to degrade quickly, so hop growers process most of them into pellets for brewing, which are vacuum sealed and can stay fresh for as long as two years.
These eukaryotes are all around us all the time, but for brewing, we can divide them into two main categories: domesticated (Saccharomyces cerevisiae & Saccharomyces pastorianus) and wild (Brettanomyces).
Our Brewing Process
The journey from grain to glass.
Milling & Malt–Handling
We move our malt and wheat from their silos into our wet mill, where the grains are steeped in hot water to hydrate the kernels. This begins the enzymatic process, speeding up our brewing process and positively affecting our lauter quality by reducing the amount of husk and chaff that would be created using a dry mill. Rather than crushing our precious malt kernels, we gently coax them into submission.
In the mash tun we combine malt with hot water so that enzymes in the malt will convert the starches into simple sugars that can be fermented. The precise ratio of grain and water is different for every beer recipe. Our mash tun allows us to do a step mash, stepping between different temperatures at which to rest for various amounts of time; in this way, we manipulate the enzymatic activity to affect the finishing gravity and mouthfeel of our beers. This is also when we add pumpkin when making beers like Rumpkin and Pump[KY]n.
The hot sugary liquid we’ve created is called wort, which we pump into the lauter tun to be rinsed and strained. Rakes slowly cut through the grain bed as water filters through, evenly extracting sugars and starches from the grain. From here, we remove our “spent grain”, which we give to a local farm to use as cattle feed. To further reduce our waste, we save the “weak wort” that remains and give it to the City of Boulder to be added to our city’s wastewater. Our weak wort provides a sugar source for the bacteria that denitrogenate our water supply.
We move our wort into the kettle to be boiled with hops, which provide bitterness, flavor, and aroma as they are isomerized. Our kettle has a state–of–the–art sensor that turns off the heat when there is too much steam and turns the temperature back on once the heat has gone down, which allows us to boil our wort for precisely 60 minutes.
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 needed to reduce the vegetative matter created by the hops. We sought out a super-concentrated form of hops and found it in the form of hop extract. It contains the same bitterness as hop pellets, but allows us to add way more, especially during our 1st addition, designed to add bitterness. At this stage, we also add adjuncts like orange peel and coriander. Our hop cooler keeps our hops at 36°F to keep them as fresh as possible.
We add the 3rd hop addition—the aroma addition—to the whirlpool vessel. We clarify the beer in the whirlpool vessel by consolidating the proteins and hops in the center of the vessel, and pump out those solids into the spent grain. From the here, we run the hot beer through a heat exchanger and a glycol chiller to rapidly chill it so we can add yeast.
It used to be that if we wanted to add a 4th addition of hops, we had to open the fermenter to add the hops, exposing the beer to oxygen. Now we dry–hop in a closed system, introducing dry hops via our hop cannon. This provides our hoppiest beers with more hop aroma while reducing the risk of oxidation and infection.
Yeast are efficient at fermentation, the process of converting wort to alcohol and CO2, along with flavor and aroma compounds. Yeast are organisms that respond to their environment by producing more or less of certain compounds, and 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. We cone–to–cone pitch when necessary, harvesting yeast from a fermented batch of beer to ferment a subsequent batch. Ideally though, we utilize our yeast propagation system to grow a small amount of yeast into a large amount of yeast to ferment our 300hl–800hl batches of beer. Our yeast prop system consists of a 2–phase process: 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 now ready to move to the 2nd phase, where the growing process continues in a bigger tank. Equipped with a positive displacement pump and in–line O2 dosing, this tank creates the perfect environment for yeast bliss.
Our cellar and lab departments monitor fermentation every step of the way. Our lab tests every tank every day to determine which stage of the fermentation/conditioning/maturation process the beers are in. It also dictates when we dry–hop our beers, when we harvest yeast, and when each beer is ready to be filtered.
Clarification & Filtration
Based on the styles of our beers, we like some beers to be hazy (i.e., White Rascal Belgian–Style White) and other beers to be brilliantly clear (i.e., Joe’s Pils and Avery IPA). Our filtration/clarification process involves our centrifuge and a 2–phase downstream "polish" filtration process. All of our beers go through our centrifuge, a machine that spins our beer at 4800 RPM to separate out solids like hops, yeast, and large proteins. If we want the beer to be brilliant, we may also run it through our polish filtration, which further clarifies the beer by removing any haze–forming particulate that made it past the centrifuge. From there, we put our beer through our in–line carbonation unit to carb each beer to our specifications, resulting in gorgeous, effervescent libations.
Canning, Bottling, Kegging
Packaging our beer is vitally important because it ensures the stability and longevity of our beers. It's the last line of defense before our beer goes out to market, and it's hugely important because our cans, bottles, and kegs encapsulate all the hard work of our brewers. Our canning line is capable of filling 309 cans per minute and has 28 precise volumetric filler valves that are accurate to +/- 1 mL. We use PakTech can toppers because they're made from 96% post–consumer recycled material, they're recyclable, and they keep the tops of our cans clean for times when you want to enjoy the Colorado rock–n–roll lifestyle and drink straight from the can! Our bottling line fills both our 12oz bottles and our 22oz bombers, at 110 per minute and 65 per minute respectively, and puts foil tops on our rarer beers that we don't offer in 6–packs. Our keg machine runs at 50 kegs per hour and fills both our 1/6 bbl kegs and 1/2 bbl kegs.
Avery began experimenting with barrel–aging in 2003 and 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. Some projects are made yearly, and some are one–off beers that won't be remade. Our barrel–aging department continues to be the most experimental arm of the brewery, and there are now more than 30 beers in our Barrel–Aged Series, including everything from beers aged in barrels that housed red wine, white wine, Bourbon, tequila, rum, Madeira, and Carcavelos.
We transfer full pallets of cans, bottles, and kegs to our 40°F warehouse so our beer stays as fresh as possible until it reaches the consumer. We also keep light away from our beer to prevent it from getting skunked, so our warehouse does not have windows and has doors that automatically open and close as forklifts to pass through. We ship our beer on 40°F refrigerated trucks and include temperature recording devices to ensure our beer is kept at a constant temperature as it travels to our distributors around the country. From there, our beer is delivered to liquor stores, restaurants, and bars, and from there, it's delivered to your mouth.