Sure, Düsseldorf’s been brewing altbier for two centuries, but it’s not your great-great-great-grandfather’s beer: Joe Stange tours the town and uncovers the ale-lager’s remarkable staying power.

If the x-axis is character and the y-axis drinkability, the better altbiers go up in that top right corner. The ideal place to drink those better ones is central Düsseldorf, Germany, capital of their homeland, where they drop via gravity from casks at pubs that make the stuff in-house.

But first, to better understand the drink, it helps to make a short detour on the way into town. Krefeld, just northwest of Düsseldorf, has a cozy little brewpub of its own named Gleumes. It has been brewing there since 1807, but not exactly the same product over all that time. These things evolve, you know.

While sitting down there to a crispy, thin-crust flammkuchen—pizza, German-style—and a few glasses of alt, a bookish beer geek might notice something odd. On the glassware, on the menu and elsewhere is the word “obergärige,” which means top-

fermented. But tacked to that word in various places is “lager” or “lagerbier.”

And there we have our first lesson in altbier. It is an ale. And it is a lager.

The alt of Düsseldorf and its environs is a lesson in hybridity. The name means “old,” but age is a relative thing. Wistful writers allude to Germanic tribes brewing along the Rhein a few thousand years ago, allowing us to imagine that they were drinking an ancient form of altbier. They were not.

In a nutshell: The Rhenish brewers of both Düsseldorf and Cologne responded to the late-19th-century lager phenomenon by making their favored tipples—what would become known as altbier and kölsch—eerily lagerlike. In modern beer-speak, an “ale” is one brewed with top-fermenting yeast. In German, lagerbier simply means one that has been lagered, or stored cold for a period of time. Alt and kölsch get both treatments. They are not ancient beers brewed to ancient recipes; they are children of the refrigeration era. They are ales… and they are lagers. And they reject neat, hermetically sealed categories.

The Düsseldorfers partly caved in to lagermania, but give them credit: They stuck with their hoppy brown beer instead of following the crowd and going gold (as nearby Cologne did). And it is a useful beer, usually below 5% ABV—light enough to refresh, compatible with a range of food and flavorful enough to stand alone. Enter the pub, have a single becher (tumbler) and move on, or have another to wash down your blutwurst. Or simply drink it all evening long.

Alt’s heart and soul surely lie in central Düsseldorf, especially in the Altstadt, the old town. Any serious altbier pilgrimage includes the old town, and many go nowhere else. The area boasts five different hausbrauereis—Füchschen, Schumacher, Schlüssel and Uerige being the grandfathers, Kürzer being the new kid—that specialize in nothing but hospitality and the city’s signature beverage.

There are plenty of hotels in the area, but a useful base camp is the Lindenhof, about halfway between the main train station and the Altstadt. It has clean rooms starting at $69 per night, breakfast included, and two other rare qualities: First, there is a parking garage on the next corner. Second, Brauerei Schumacher is across the street. The stand-up sidewalk tables beckon to hotel guests peering out of their windows. It is a natural first (and possibly last) stop on the altbier crawl.

Though outside of it today, Schumacher was originally built in the Altstadt in 1838, and is the oldest of Düsseldorf’s surviving altbier houses. It’s been sitting in its present spot on Oststrasse since 1871. It is a wide and rambling place; the front stube or barroom is cozy enough, often populated by men in work clothes stopping by for a quick one. From that spot it is dangerously easy to get the waiter’s attention, as he drops off more bechers and ticks them off on your mat to be totaled up later. Casks arrive from the cellar via elevator, then fill glass after glass to be carried away with haste. Schumacher is a well-lubricated machine whose function is to well-lubricate its guests.

From Schumacher, it is a healthy 10-minute walk west to the old town. With affection, locals say the Altstadt is the “world’s longest bar.” But on which end to start?

The southernmost altbier house is the one that makes the most distinctive drink. Uerige’s version has a profound hop bitterness that makes it stand out; it is addictive, and for that reason it might have the most devoted followers. Among the other four grandfathers, Uerige is the baby. It only came along in 1862, after all, though the building itself has a deeper brewing heritage; the land-tax register of 1632 reports a baking-brewing house on the same site. The pub has the age and Gemütlichkeit, but its evening crowd always appears a bit looser and more raucous than the other brewpubs. Like its beer, Uerige has an edge.

The next block north is Bolkerstrasse, and the Schlüssel brewhouse, marked by a lit-up key (schlüssel = key) illuminating several stand-up tables. Stepping through the door, the pub’s interior appears to be an optical illusion, as if mirrors made those rafters and tables and drinkers go on and on forever. Strolling back reveals that it’s no trick: The place just sprawls, and yet most evenings it appears that few of those tables have an available seat. The menu is studded with meat-heavy regional fare; the hausschlachtplatte or slaughter plate eliminates the need to choose among three sausages: white, garlic and blood.

The popular Füchschen is the Altstadt’s northernmost brewpub. Its narrow stube is often standing-room-only, while the main dining room tables are usually reserved. Still: Come to stand, book ahead or steal a table, whatever it takes. The “little fox” makes a polished and beguiling altbier, malty but balanced by a bitterness that builds. It’s a civilized beer in a civilized pub, so it’s hard to imagine reaching the point at which one would need the strange exhibit in the men’s room: Near the door is a special sink designed for vomit. The sign above it urges guests to “please dispose of waste in its proper receptacle.”

Between Schlüssel and Füchsen lies the new kid, Brauerei Kürzer. This one is not like the others, and therein lies the attraction. Kürzer is a narrow and modern pub with splashes of exposed brick and none of the old-fashioned trappings. Its alt—rustic, bready and dry—fits in well enough alongside the grandfathers, but beyond that things get weird: The bar’s centerpiece is the world’s only “bottomless” altbier cask. The barrel is transparent and frequently replenished by two shiny holding tanks suspended up in the rafters. It never goes empty. It’s an impressive piece of high-tech gimmickry for a younger generation, and proof that regardless of its age, altbier can never really be old.