Serious About Separation
Craft breweries of all sizes are using centrifuges to reduce production time, fine the beer, reduce waste, and perform a multitude of other functions. It’s made for higher profits and pays for itself. We spoke with Three Weavers Brewing Company to discover all the ways centrifuges have benefited craft breweries.
CRAFT BEER, AS MUCH
as it is marketed as an artisanal and handmade product, is still an industrial product. A brewery is more like a factory than a workshop, and the brewers who tirelessly chase greater efficiency and consistency are often the brewers who make the best beer. At Three Weavers Brewing Company in Inglewood, California—a two-year-old brewery that’s growing fast—industrial isn’t a dirty word. In 2016, the brewery completed major capital improvements that will more than double its production capacity. Alongside more fermentation tanks, a grain silo, and a brewhouse upgrade, Three Weavers added a piece of equipment that’s becoming increasingly popular with craft breweries: a centrifuge.
Weighing almost a ton, the GEA HB-05 sits on a moveable skid among the fermentation tanks and has changed the way the brewery operates. It has reduced production times and has largely supplanted the filtering and fining chores in the brewery while increasing consistency and shelf stability and even improved flavor. Three Weavers now makes better beer faster than ever.
“It’s like magic,” says Three Weavers Brewmaster Alexandra Nowell. “More control, more aroma, less waste—it’s all upside.”
The most common use of a centrifuge— also known as a separator—in a craft brewery is to clarify beer before packaging. An alternative to (or sometimes a supplement to) fining agents, long conditioning times, and filtering, centrifugation offers a brewer more control over finished beer turbidity while increasing efficiency and reducing the time it takes to go from grain to glass.
A centrifuge separates solids, such as yeast, hops particles, and the long-chain proteins responsible for haze, from beer through the judicious application of centrifugal force. The centrifuge acts like a high-powered pump, pulling beer from a fermentor and pushing it into a spinning bowl outfitted with a stack of cone-shaped plates. As the beer spins around the centrifuge bowl, the heavier solids in the liquid are forced to the outer edges of the cone, while the lighter liquid flows up the center of the assembly, out of the centrifuge, and into another tank. All the separated solids collect in a holding tank that’s purged at regular intervals. It’s simple physics applied with fine-grain computerized control, and it’s a technology that’s popular with large-scale craft breweries because it makes the brewery more efficient.
Most separators at breweries are manufactured by GEA Westfalia or Sweden’s Alfa Laval. Michael Fair, a sales engineer for GEA, has seen interest in centrifugation surge as craft brewers strive for more quality and consistency in their product. Fair says that while ten years ago it was mostly breweries making more than 15,000 barrels per year who added centrifuge equipment, in today’s competitive environment, and with smaller units scaled to craft breweries, adding a separator makes sense for breweries making far fewer than 10,000 barrels annually. Even breweries making as few as 2,000 barrels of beer a year have added separators to their process. As Fair tells brewers shopping for a centrifuge, it’s equipment that a brewery can grow into.
Three Weavers made about 5,000 barrels in 2016, with the goal to push production capacity toward 10,000 barrels after 2017. Apart from the initial costs, Nowell says there is no major downside to operating the centrifuge. Compared to the previous process of filtration, “the separator is a closed system,” Nowell explains. “The beer doesn’t see any atmosphere until
it hits the glass.” This reduced oxygen pickup, better batch-to-batch consistency, and what Nowell describes as a more vivid hops character are some ancillary benefits.
The GEA separator at Three Weavers is loud, however—loud enough that the brewery runs it only while the tasting room is closed. “It isn’t conducive to good conversation,” Nowell shouts at me over the incessant drone as the separator spins through a batch of Expatriate IPA, and as if to punctuate her statement, valves in the centrifuge automatically slam shut, and high-pressure rinse water jets through the solids holding tank. A moment later, and after another deafening actuation, a green-hued slurry of yeast and hops matter sprays from a waste discharge port. The whole operation—purges and all—is largely automated. An array of sensors feeds data into the control computer on the machine where the operator can adjust flow rate, tweak the outgoing turbidity levels (see “Flow Rates and Turbidity,” page 54), or manually flush the holding tanks at any time. But largely, he/she just needs to make sure nothing goes wrong with the preconfigured programs.
Efficiency—getting maximum productivity with minimum waste—is the lifeblood of industry, and a centrifuge increases the efficiency of a brewery in a few ways. First, it speeds up beer production by reducing the time it takes for a beer to settle after primary fermentation. Instead of waiting for the yeast to flocculate—naturally drop out of suspension—the centrifuge mechanically separates the yeast from the beer, saving as much as a week of conditioning time. There is also time saved in the brite tank during the final pre-packaging conditioning phase. Nowell says that Three Weavers’ flagship IPA Expatriate would spend about
five days in the brite tank as more cold break proteins and yeast dropped out of suspension, but the separator reduced the brite tank residency to just 24 hours. Not only is a batch ready four days sooner, but the production bottleneck at the brite tank is also removed.
Another important way that a centrifuge impacts brewery efficiency is by reducing waste. How often have you racked a homebrew after primary fermentation, careful not to disturb the yeast cake at the bottom of the fermentor, and then dumped a pint or two of sludgy liquid trub down the drain? At the 5- or 10-gallon batch size, this loss of beer to trub might make us flinch a little, but it’s a literal drop in the bucket compared to the losses seen in a commercial brewery’s fermentors. The sludge that settles to the bottom cone of a cylindroconical fermentation vessel is about 50 percent beer, and a centrifuge will happily process this slurry of yeast, protein, hops matter, and beer, reclaiming much of what many brewers write off as a loss. In heavily dry-hopped brews, extra hops matter compounds the problem, but a calibrated centrifuge will spin out all those solids. Nowell says that before installing the centrifuge, they were careful to package beer only from above the “fluffy layer,” the results from fining with Biofine (a vegan-friendly fining agent used by many commercial breweries to clarify craft beer). With the centrifuge, Nowell can package another eight kegs’ worth of beer from each 60-barrel fermentor. That’s almost a thousand pints of beer that the brewery can now sell instead of dump.
This all means that a brewer can sell more beer while also reducing the costs per batch of beer (“Biofine is expensive!” quips Nowell), and these are the kinds of business-friendly numbers that bankers love. While the installation of a centrifuge can range from $100,000 to more than $500,000, it’s the kind of capital expenditure that brewery owners are finding it easy to finance, and it’s an investment that pays for itself quickly. GEA’S Michael Fair says that about 90 percent of the centrifuges he’s sold to craft breweries take only 12−18 months to pay back the initial cost.
On the Hot Side
In addition to the gains that a centrifuge can provide post-fermentation, several breweries are turning to centrifugation to improve efficiency of wort production. Configured for the hot side, a centrifuge can take the place of a whirlpool in the brewhouse, separating clear wort from trub, hot break, and hops particulates post-boil. A whirlpool tank acts as a low-tech centrifuge that facilitates the settling of trub and other solids as clear wort is drained off, but a powered separator can do this job faster and with more control. Craft breweries can use one unit for both hot side and cold side separation, or they can dedicate a centrifuge to each process. Fair says Ballast Point recently added a dedicated hot side centrifuge to their Miramar brewhouse that reduced the knock-out time on the 300-barrel boil kettle to just 58 minutes. Because of the increased speed and efficiency (as much as 5 percent more wort can be collected via centrifuge than traditional whirlpool techniques), Fair expects hot side separation will be the “brewery process of the year” in 2017 and 2018.
While a centrifuge doesn’t make sense for every craft brewery, size and production capacity are no longer the limiting factors they once were, and even modestly sized craft breweries are integrating centrifugation into their process. At Three Weavers Brewing, the quality and control the centrifuge supports are a key to the brewery’s future growth.
Clockwise from top » The GEA centrifuge at Three Weavers Brewing; a sight glass shows off beer post-separation; turbid beer flows in, and solids are separated from the liquid; a bucket of separated solids after a run.
A pre-separation sample on the left with a post-seperation sample on the right.