Neil Witte, a Master Cicerone and beer industry veteran, puts it like this: “Craft-beer consumers want new stuff all the time, but they also crave authenticity.”  It’s a duality at the core of American beer culture and a driving force behind the incessant innovation on which the industry is built. From the first American pale ales brewed in the late 1970s to the renaissance of lager styles on taps today, American brewers have gotten quite good at taking Old World ideas and tweaking them for American palates. This isn’t limited to borrowing styles from Europe; some brewers and publicans have taken to borrowing service techniques endemic to beer cultures older than our own.

Take the rising popularity of the “slow pour” pilsner and the focus it places on the beer’s foam—this trendy service style often is enabled by a special piece of equipment that uses a sideways approach to the act of pouring a pint: the side-pull draft faucet.

Typical draft faucets are functional and boring. Nobody gives them much thought until a beer isn’t pouring just right. But the Czech-style side-pull draft faucets aren’t only an attractive piece of metal. They have two key differences that allow for increased control and interesting alterations to a beer’s flavor.

Magic on the Side

Instead of the open-or-closed plunger valve, side-pull faucets feature a ball valve, and this allows for a range of flow rates without introducing turbulence to the beer. But that’s only half the magic of the side-pulls; there is also a micro-screen placed just before the opening of the faucet’s spout. As the pressure in the draft system pushes the beer through the screen, carbonation is forced out of suspension. Because the mesh is so fine, the bubbles created are comparatively tiny. The resulting “wet foam” from the side-pull faucet is quite different from the usual head atop a pint of draft beer. (Think of the silky, full-bodied foam in a flat white or cortado espresso drink, instead of the coarser, drier foam in a cappuccino.)

“The flavor of the foam is just different,” says Ashleigh Carter, cofounder and head brewer at Bierstadt Lagerhaus in Denver, Colorado. Carter says they were looking for something different when designing their taproom and draft system. A chance encounter with a tap dedicated to Pilsner Urquell at a New York City beer bar several years ago led her to the side-pull faucets. They are large and eye-catching and almost necessitate a performative pour; Carter quickly discovered that the side-pull faucets do more than just look cool. “They are everything we love about draft faucets: They look striking, they pour great, and you can really dial in the way they dispense.”

The flexibility inherent in the design of the side-pull faucet is often on display in Czech pubs, especially where Pilsner Urquell flows freely. Drinkers of the influential lager can even order their pours in three different ways. The standard pour, known as the hladinka, features three fingers of foam atop the golden beer, while the šnyt is slightly more than half foam and a little less beer. Then there’s the fabled mlíko pour—a nearly full glass of creamy, wet foam with some liquid beer at the bottom. “They are each a different experience of flavor and texture,” says Carter. The mlíko, in particular, is an interesting way to keep on enjoying beer when you’re not sure you want another whole pint—all the restraint of ordering a cheeky half pint, while still getting to hold a full-sized glass and sip along with your mates. (And remember, this is dense, wet foam that is readily sippable, unlike a cap of sticky, dry foam from an improperly poured pint. It’s really a novel and pleasurable experience.)

In an era of the “boss pour” (that peculiar Instagram-fueled fad of pouring, mostly hazy IPAs, to the very bead of a glass’s rim) and customers demanding a “full glass” of beer when any foam is left in the glass, American beer drinkers seem utterly unready for the mlíko. But the side-pull faucets are more about the quality of foam and how that affects the drinking experience than the more extreme example of the mlíko pour.

Slow and Easy

Poured in stages to develop a firm foam cap that will rise well above the rim, a “slow pour” can take several minutes to complete, but the result is as tasty as it is visually dramatic. “It creates a tower of flavorful foam,” says Jake Miller, cofounder and brewer at Heirloom Rustic Ales in Tulsa, Oklahoma. Miller is a pilsner partisan and a particular fan of the slow-pour service. The side-pull faucet makes the slow pour easier to achieve, and the effects on flavor are threefold. First, that dense cap of wet foam helps to hold volatile aromas in the beer. Second, the breakout of CO2 caused by the faucet’s mesh screen means the liquid beer has a softer mouthfeel (and a “rounder” flavor, according to Carter). Finally, the flavor of wet foam is closer in flavor to liquid beer than typical dry foam would be. Miller calls it a “mirror image” of the liquid beer in the glass, not the funhouse mirror of distorted flavors on display in typical dry foam.