Why the Weizenbock Deserves Our Attention | Craft Beer & Brewing

Why the Weizenbock Deserves Our Attention

In the world of beer, and certainly German beer, weizenbocks are strange unexpected beers.

Jeff Alworth 3 months ago

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On a crisp Bavarian day 7 years ago, after a lunch consisting entirely of sausage, I encountered a very unusual beer. In the little town of Kelheim, about sixty miles from the Czech border, Brewmaster Hans-Peter Drexler was leading importers through a tasting of G. Schneider & Sohn weissbiers. Schneider is among the most traditional breweries in the world and makes nothing other than wheat ales—no helles, no dunkel, no märzen lagers. Bavarians have been making wheat beers a very long time, however, and the variations available offered quite a menu of possibilities—a point Drexler drove home when he handed us glasses of a strong liquid the color of a hazelnut shell smelling of warm bread, chocolate, and ripe banana.

Aventinus is the brewery’s weizenbock, the most-lauded in the world, and it is uncommon by any standard. Unlike the drier lagered bockbiers that proliferate seasonally in Bavaria, Aventinus is made with the traditional weizen yeast strain, which gives it a sweet and decadent palate. The familiar yeast-driven flavors of banana and clove are present, but they’re more concentrated while also being more peripheral; the body and booze of the beer crowd them with waves of chocolate, toffee, and candied fruit, all warmed by alcohol and enclosed in folds of velvet. In the world of beer, and certainly German beer, weizenbocks are strange unexpected beers.

But let’s not kid ourselves. Though tall sexy glasses of opaque (and hazy long before hazy was cool) ales are the very picture of a Bavarian biergarten, their ubiquity conceals a deeper truth: all Bavarian weissbiers are really strange beers. Weizenbock may be the oddball of the family, but it’s the distance between The Addams Family’s Morticia and Pugsley, not Morticia and Leave it to Beaver’s Beaver Cleaver. In a traditional brewery such as Schneider, nearly every step in the process has unique elements that distinguish it from breweries everywhere else in the world. Bavarian weissbiers may not be quite as exotic as lambics or Scandinavian farmhouse ales, but they’re not far off.

Let’s start with the mash tun, the place an English cask brewer would conduct a single-infusion mash. Ales are simple, right? Not weissbiers. In order to coax the character he wants from Schneider’s ales, Drexler trots his 60 percent wheat mash through seven rests. They start just above blood temperature, far lower than most brewers mess with but critical for a weissbier. That’s when the barley and wheat release ferulic acid, a compound (technically a “phenolic phytochemical”) that will be converted by the right kind of yeast into those clove-flavored phenols.

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“We are very interested to have the raw materials that bring a lot of the ferulic acid to the wort,” Drexler says. “It comes from the barley and the wheat—but most of it comes from the barley.”

It can only be freed from the grain in a narrow temperature band between 104 and 122°F (40 and 50°C). From there, the mercury will pause every six to thirteen degrees as the mash bed slowly rises to mash out at 172°F (78°C). Just to add a bit of fun complexity to the process, a one-mash decoction is thrown in during one of the steps.

The one unremarkable step in the process comes next as the wort goes through an hour-long boil, receiving a couple of small hops additions, before proceeding to fermentation, where things get weird again. In order to make a proper weissbier, brewers must pitch the right kind of yeast—an old strain of a type largely eschewed by modern brewers for precisely the reasons weissbier-makers prize it. This type of yeast is known as “phenolic off-flavor positive” (POF+) by those more recent brewers with a prejudice against clove-scented beer.

Because Drexler has prepared his wort by releasing ferulic acid, that yeast can now turn it into a tasty-sounding compound known as 4-vinyl guaiacol, the actual source of the flavor of clove in weissbier.

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Yeast cells are living organisms, and they behave differently depending on where they live—just like any of us. In modern fermentors, which are tall and narrow, they are docile and unflamboyant. The height and pressure inhibit yeast expression. So, too, does the cap on top of the fermentor. That closed cramped environment doesn’t allow the yeast to let its hair down. A wide, open fermentor is the way brewers get the most expressive yeast flavors. Contact with oxygen and low pressure mean much higher production of esters—isoamyl acetate, the characteristic banana flavor, as well as other minor players—and phenols.

Drexler had been brewing at Schneider for decades when I visited him. He must have walked into the fermentation room hundreds of times. Still, when we stepped into it that day, he visibly winced. “The challenge of this system is the hygienic problem of the open fermentors,” he said. “Everything has to be very, very clean.”

Humans carry all kinds of yeast and bacteria on their bodies, and his anxiety told me exactly how clean he thought we were. Giant fermentors dotted the bubbling foaming sanctum, their tops rising waist high and filled with roiling beer. Those happy yeast cells were busily gobbling up Drexler’s carefully composed wort and turning it into a kind of beer that had been made in that area for more than 400 years. The room smelled incredible.

As we exited, Drexler said rather casually, “After 5 to 6 days or so, depending on the beer style, we move straight from the first fermentation to the bottling. On the way, between fermentation and bottling, we add the ‘food,’ the speise, and that’s it.” Wait, what? Straight from these vessels to the bottle? That seemed impossible, but it was true. A few years before I arrived, Schneider started making alkoholfrei beer (nonalcoholic), and they had to install conditioning tanks to make it. For the 14 decades the Schneiders have made beer, they’d never owned tanks or had a reason to. Speise is a specially prepared wort that brewers add to the finished beer to keep feeding the yeast cells so they create a lively burst of effervescence, critical to rousing fluffy heads. (At 3.5 volumes, Schneider Weisse is about 40 percent more lively than a standard beer.)

Weizenbock is a strong or “starkbier,” which makes it stand out from the eminently sessionable family of standard weissbiers. But aside from its strength and what that does to flavors it contains, weizenbock does not require special techniques—beyond those used to make any weissbiers. When I later wrote The Secrets of Master Brewers and asked Drexler to provide a standard weissbier recipe, he said it was easy to turn it into a weizenbock by using the same formulation and ingredients—just at a higher gravity.

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After we’d finished the tour, I mentioned how surprised I’d been by the brewery. I didn’t expect it to be so unusual. That was the way of weissbier, he agreed. “For me, wheat beer is terrible to produce,” he said. “There are so many screws you have to turn. It’s crazy. And these open fermentors are very hard to control. But the result is amazing if everything works perfectly.”

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