This is especially interesting because I have so little information about the beers of the Rheinland. Especially Altbier.
I can’t be arsed to translate the chapter. I’m just going to summarise it for you. Here goes.
Düsseldorfer is a beer that’s especially popular in the summer in the Düsseldorf region. It’s half-dark and is manufactured in a similar way to Kölsch. It’s brewed using the two mash method, either with two thick mashes or one thick mash and a lauter mash.
It isn’t very highly attenuated because the high hopping rate is enough to keep it sound for a long time. The colour comes from well roasted Farbmalz, enough is used to give it a cherry red colour, a shade paler than Münchener.
It’s hopped at a rate of 2.5 pounds per 50 kg of malt. A third of the hops are added as the wort is being run into the copper, anther third after an hour of boiling and the last third 45 minutes before the end of the boil. 8 - 10% of the hops are added right at the end, when the steam has disappeared. It has an OG of 9.5 – 10%.
With very hard water it’s mashed in at 35º C and then the temperature is raised to the saccharification temperature of 70º C by mixing in boiling water. It’s held at this temperature for 30 to 40 minutes. Mashing then proceeds in the usual way. The mash is boiled for 15 to 20 minutes.
It’s pitched with top-fermenting yeast at a temperature of 10º C. Fermentation takes place in tuns and lasts 4 to 5 days. After primary fermentation it’s lagered at 1 to 2º C in the same way as Lagerbier. It isn’t bunged, the casks being filled to the top and then the bung lightly fitted. After 6 weeks it’s served filtered and unbunged. Like with Kölsch before it leaves the brewery boiled hops are added at the rate of a half pound per 30 litre cask.
Source: Olberg, Johannes (1927) Düsseldorfer, obergärig in Moderne Braumethoden, pp 67-68, A. Hartleben, Wien & Leipzig.
Now isn’t that interesting? I’m particularly happy that it’s so clear about the colour: cherry red, a little paler than Münchener. And also where the colour came from: roasted malt.
2.5 pounds per kilo works out to about 8.25 lbs per quarter. Which is a bit more than a London Mild during the 1920’s (their rate was 6-7 lbs per quarter) and a bit less than Pale Ale (10-12 lbs). Based on an OG of 10º Plato, I calculate the rate at about 1.4 lbs per imperial barrel. Which is quite a heavy hopping rate for the continent.
The mashing scheme is far more complicated than those employed in the UK.
Primary fermentation looks to be very cool for a top-fermenting yeast, so I’m surprised it was over in as little as 4 or 5 days. At six weeks, the lagering is quite short. Then again, the gravity wasn’t that high. As it wasn’t bunged, the CO2 content couldn’t have been that high.
But most intriguing of all is the wet hopping. And at quite a high rate – that’s the equivalent of about 2.5 lbs per imperial barrel.