If you’ve been a brewer long enough, it’s probably happened at least once: Something truly strange turns up in a shipment of malt—links of chain, a forklift light, plastic pellets, a cargo strap, half a pair of broken scissors. However, those moments are rare. Typically, the malt you’re about to brew with is clean, dry, and free of extraneous objects. So, when you do end up with something strange in the Super Sac, the one thing you really don’t want to find is evidence of insects or other pests.
“If you discover a pest, it’s already too late,” says Matt Drew at Montana Craft Malt in Butte. “You have to assume if you find a pest in any part of your facility, it’s everywhere.” Drew, who worked as a maltster for a couple of years before landing at Montana Craft Malt as marketing director, is speaking from experience. When a small green beetle appeared in his employer’s malt storage facility, it was “everything he could do to keep the grain clean.”
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While he’s no longer steeping, germinating, and kilning barley, he does have recommendations for brewers: Develop standard operating procedures for handling and storing malt, and have a plan for dealing with rodents, birds, and insects. Maintaining cool, dry conditions with ample airflow is the name of the game because lower temperatures and drier conditions tend to increase shelf life.
However, it’s easy to let you guard down.
Woven polypropylene sacks can tear, paper malt bags are prone to puncture, and malt is hydroscopic, meaning it will absorb moisture from its surroundings—especially if bags are stored in a humid environment or aren’t properly sealed. Damp malt won’t mill properly, and it can become moldy, which leads to oxidation. Malt also will absorb ambient odors, further compromising its quality. Meanwhile, mice can fit through openings as small as a dime. In other words, stay vigilant.
As Drew says, the one time you’re not looking for a spoilage issue is when something will happen.
Clean Like You Mean It
At Mirror Image Brewing in Frederick, Colorado, north of Denver, managing partner and head brewer Theresa Schirner has been there.
“When I became head brewer in 2019, we consolidated from two units to one,” she says. “As we were cleaning and rearranging the back of house, we ran into some flour beetles. There were oats sitting on the top of our grain shelves [that] had probably been there a while. The beetles had found their way into the bag, created several generations of family members, and then outgrew their space and moved—fell—down to the next shelf. The hardest part of the removal process was that you could not disturb the bag too much without [the beetles] falling onto the next item, so we had to very carefully remove [the bags] into plastic bins and then transport them out.”
Shirner says it took several days to get rid of the beetles and establish a clean and sanitary storage area, but Mirror Image has been beetle-free ever since. Today, the brewery produces about 275 barrels a year, typically working through its grain orders in about three weeks. These days, the most common pest the brewing team faces is camel spiders. Regular dusting, web removal, and the judicious use of food-grade bug spray keeps these arachnids at bay. Meanwhile traps and a healthy amount of vigilance tend to be enough to deter mice during Colorado’s chilly falls and winters.
For anyone looking to avoid a pest problem at their own facility, Shirner has straightforward advice: “Take the time to organize and clean,” she says. “Whether it is dusting, mopping, or getting a good scrub in, it's good practice. Set the expectations with your team so that being organized and clean is in your daily practice.”
At Waypost Brewing in rural Michigan, co-owner and head brewer Hannah Lee says that regular cleaning and maintenance are her watchwords, too. With the brewery so open to the outdoors, adequate ventilation is not a problem. That said, she does appreciate the pest-control help she gets from some dedicated volunteers: a pair of farm cats.
“Fortunately, we haven't had anything too terrible to deal with here on the farm—knock on wood,” Lee says. “Prevention, regular cleaning, [and] maintenance helps. And of course, the two cats seem to be highly efficient at their jobs.”
Order Small, Order Often
Cleanliness is certainly important at any facility where food or drink are the final product. At Wild East Brewing in Brooklyn, New York, cofounder and head brewer Brett Taylor adds another rule of thumb: Use your malt as quickly as possible.
Taylor brews on a 30-barrel system. He says he generally orders enough grain for one to three batches of beer, no more than two pallets’ worth of 50-pound bags. Once he’s received a shipment, it’s first in, first out. Rarely does he have malt on his pallet rack for more than two weeks.
“We're pretty hand-to-mouth for financial, space, and logistics purposes,” he says. “I pay dearly for my 7,000 square feet [650 square meters]. So I can't have pallets taking up too much space at any given time.”
Generally, raw grain can be kept for two years without compromising quality, while malted barley retains its quality for up to a year when stored properly. For highly kilned malts, that timeline can be longer. Yet for Wild East and other smaller breweries that are trying to balance profitability and efficiency while serving a relatively small geographic area, fresh malt is rarely a concern. Taylor says that his lagers turn over so quickly that he never really loses sleep over the best-by dates on his Rahr or Weyermann malts.
“My bigger concern is making sure I reserve enough floor-malted Bohemian pilsner malt before it sells through,” Taylor says. “Kind of the opposite of worrying about freshness.”
In Western Massachusetts, Element Brewing co-owner and brewer Dan Kramer usually orders just one pallet at a time, aiming to work his way through it in two to three weeks. Kramer and his business partner Ben Anhalt purchase pre-milled malt, which has a shorter shelf life. By working quickly through a small supply and keeping storage areas clean, they have avoided infestation for more than a decade and never had the need for an exterminator.
“We try to keep our inventory to a minimum,” Kramer says. “We go through our base malts as quickly as possible and store partial bags of specialty grain in a stainless-steel container. We don’t have a mill, so we buy pre-crushed grain, which is another reason we try to use it quickly.”
Stay Cool, Keep Dry
Across the country in Seattle, Washington, Stoup Brewing also tries to get through open bags of malt as quickly as possible. Co-owner and head brewer Brad Benson says they order base malt by the truckload—48,000 pounds at a time (about 21,800 kilos). They store the grain in a silo that gets inspected for pests quarterly, while a sealed shipping container protects specialty bagged malts from pests and spoilage. While Benson says he knows of a nearby brewery that had an infestation of red flower beetles in its silo, the only nuisances Stoup has contended with are mice and rats.
Instead of pests, he worries about moisture ingress during western Washington’s lengthy wet season, which can stretch from mid-October well into April. Dry malt performs best when it’s time to mill and mash, and commercial malt typically has a moisture content between 3 and 6 percent. At Stoup, Benson stresses the importance of maintaining air movement in malt-storage areas.
“We run a dehumidifier in our bagged malt room—especially in the Seattle rainy months—which helps to keep the malt from picking up moisture,” Benson says. “Sealed bags of malt fare well. However, open bags, pre-milled malt, and flaked grains cause the biggest problems. Always be checking on your malt. Our eyes and palates are the best way to find problems early and get them fixed before they get too big.”
Patrick Ware, cofounder and head of brewing operations at Arizona Wilderness Brewing in Gilbert, Arizona, also stores his malt in a grain silo—albeit one that holds 6,000 pounds (about 2,700 kilos), as opposed to Stoup’s 60,000-pound capacity silo. Ware says the relatively small size of the vessel works well for the brewery; it typically uses that much malt monthly, helping to ensure the supply is always fresh. Sourcing all of his base malt from Sinagua Malt, Arizona’s first commercial maltster, is another way that Ware can be assured of freshness.
However, as with Benson in Seattle, it was moisture and the problems that it can generate that proved to be a source of frustration for Ware in 2021. Not usually an issue in the Grand Canyon State’s dry climate, mold reared its ugly head at Arizona Wilderness when it found its way inside the brewery’s tubular drag conveyor system.
“The mold issue [was] very challenging because the system is somewhat complicated,” Ware says. “The mold [was] inside the Chain-Vey system, which means the entire system [needed] to be dismantled, cleaned, and resealed before we [could] order bulk grain again. For us it comes down to closing the malt intake every time we use it, otherwise rainwater can get in the system.”
Ware did overcome the mold issue, but at considerable expense. Until a local company was able to clean the entire system, his brewing team had to go back to lugging bags of grain around. Now that he’s dealt with it, Ware says he isn’t likely to run into mold trouble again. With the benefit of hindsight, he says that his situation could have been avoided and that he’s learned not to cut corners when installing bulk-malt storage.
Overall, when it comes to handling and storing malt, there’s a larger lesson that should be easy for any brewer to remember: Preventing problems is almost always cheaper than resolving them.
Do you have stories of pests getting into your malt supply or creative solutions for what to do about it? We’d love to hear them. Contact us here, and we may be able to include them in the next issue.
