Altbier predates the lager revolution by three centuries. While Bavaria standardized bottom-fermenting yeast in the nineteenth century, Düsseldorf's guild brewers kept the medieval top-fermenting method alive, aging their copper-hued ale in cool cellars — alt meaning old in the dialect — and pouring it by gravity from wooden casks. By 1850 the Altstadt harbored forty-seven licensed brewhouses; today five remain, each occupying the same stone-vaulted cellar it has held since the 1800s. The beer itself is brewed to near-identical recipes: dark Munich malt, Hallertau hops, open fermentation at eighteen degrees, then cold-conditioned for four weeks. The result is a style so geographically specific that Kölsch, brewed forty kilometers upriver in Cologne, is considered a rival tradition rather than a sibling. A düsseldorf altbier tour threads the quarter's cobbled lanes, linking brewhouses that function as both production facility and public taproom. Zum Uerige, founded in 1862, operates on a gravity-pour system: casks rest on racks behind the bar, and servers — called Köbes, dressed in blue aprons — carry trays of cylindrical 200-milliliter glasses called stangen. The house rule is automatic refill; an empty glass signals the Köbes to pour another. Zum Schlüssel, opened in 1850, brews a maltier variant with caramel undertones, served in the same stangen format. Füchschen, established in 1848, occupies a double-height hall with cast-iron columns and pours the lightest of the district's alts, closer to amber than mahogany. Schumacher, dating to 1838, is the oldest surviving brewery and the only one to bottle commercially. Kürzer, the newest at 1733, sits on Kurze Straße and brews the hoppiest expression, with a pronounced bitterness that balances the malt. The Altstadt's layout favors slow movement. Alleyways connect squares named for medieval trades — Schneider-Wibbel-Gasse, Andreasstraße, Bolkerstraße — and each brewhouse opens onto a different node. Guided brewery tours cross the quarter on foot, pausing for tastings at three or four stops, while culinary variants add rye bread, mustard, and Rhenish sauerbraten between pours. The district operates without formal closing hours; brewhouses serve from midday through midnight, and the walking distance between any two rarely exceeds three hundred meters. The result is a beer culture built on drift rather than destination, where the route matters as much as the pour.