Franconian Beer Message Board

"Andreas Gänstaller uses it every time he brews lager.  
“The wort streams out really clear,” he says. “The beer is much more clear because all the bad stuff goes away in the steam.” Notably, that “bad stuff” includes DMS. Once the wort temperature drops to about 75°C (167°F), Gänstaller drains the wort to a more traditional chiller to bring the temperature down to 10–11°C (50–52°F), then on to fermentation."

"When they updated the brewhouse in 2000, the Zehendners got rid of something besides that second decoction step. At one point, Zehendner produces a photo of a young man with a hose cleaning what appears to be a coolship? “That’s me,” he says.

The coolship in the picture went to nearby Schesslitz and the Barth-Senger brewery, which closed in 2012. Now his old coolship is just sitting there. It may yet return. “I told them, ‘Before you send my coolship to America, I’ll buy my coolship back!’” “For 30 years we left the wort overnight in the coolship, and in the morning we gave it to the fermentation.” Then one day he did a lab analysis of the beer and found small amounts of bacteria. They were not spoiling the beer, as far as he knew, but the potential was there. So they switched to more modern chilling methods.

Let’s be clear: Coolships do not make beer sour—not necessarily. They have become part of the myth and legend around lambic beers, but much of that magic happens in the barrels. Coolships used to be a fairly common sight in breweries of all sorts.

Like elsewhere, they have become rare in Germany. Gänstaller says he knows of only four in Franconia that are still used. Just east of there, in the Oberpfalz region, the communal Zoigl breweries still have coolships in their attics and allow the beer to cool there overnight—with few, if any, ill effects. On the other side of the country, the famed Uerige altbier brewery in Düsseldorf still uses an attic coolship for an initial drop in temperature, much like Gänstaller. There may be a few others around Germany. But for the most part, they have disappeared.

Now, Zehendner says he might try it again, but in a way similar to his friend Gänstaller, who brews fifteen miles from here—by moving it to a traditional chiller after an initial drop to 75°C (167°F). “I think now you can do it better,” he says. Are these the early stirrings of a coolship comeback?

At Gänstaller they add hops to the coolship before running the wort in.  Almost like whirlpool hopping done in modern IPAs.  I'm gonna have to try that in my next homebrew Kellerbier and not feel guilty about it.