“Lautering can feel like handling a rattlesnake,” says Andy Hooper. “You don’t want to make any sudden movements, or you’ll get bit.”
Now the director of business development at Barnum Mechanical, based in Loomis, California, Hooper previously was brewmaster at Seismic in Sebastopol, California, for more than six years. He has a keen eye for the details that can make or break a brewing process.
In his snakebite analogy, the grain bed is the rattler, and the dreaded stuck mash is the bite. Any quick or extreme change to a carefully balanced system during lautering is risky.
“If you open a valve too fast, you might disturb the grain bed,” he says. Separating sweet wort from spent grain is a straightforward task, but every brewer knows there’s some mystery mixed in with the mash—even academic research papers have called lautering a “black-box operation.” Beyond our gaze, there are complex fluid dynamics at play; not all the variables that determine flow rate and extraction efficiency are obvious.
Every detail—from temperature and water pH to the structure of the mash’s starch granules to the design and geometry of the lautering vessel—impacts the efficacy and permeability of the grain bed. And that bed is built at the bottom of a steaming vessel filled with murky malt porridge.
Yet every brewery needs to rely on that process, as hiccups can cost time and money and potentially affect the character of the beer—not to mention be a deep source of frustration. So, let’s look closer at what’s going on in the bottom of the tun and—while hearing from a few brewers who’ve given it more thought than most—consider how best to manage the inputs and outputs of that black box.