Spontaneously fermented, immensely high gravity, an extremely slow fermentation, an ridiculously long boil. It scores highly in the odd stakes. It sounds like it might be a relative of Braunschweiger Mumm, except with more alcohol.
Joppenbier is in many respects very interesting. It is made from a highly concentrated wort - the Saccharometer degree is about 49 percent.
From 1000 Kg malt and 5 Kg hops approximately 10.5 HL beer is produced.
The mash is made by the infusion method and the wort which is drawn off is - to obtain the specified concentration - often boiled more than 20 hours. The wort is cooled down to down to 12.5 º.
The fermentation is a so-called sponataneous fermentation. Fermentation usually begins in July - although it is the same whether the beer is brewed in January or April. The wort is first covered with a thick blanket greenish-white mould; when the mould spores are in sufficient quantity to force their way into the wort and to grow to a very characteristic yeast, then the fermentation begins, which only in September subsides enough so that the beer becomes clear and can be drawn off. The attenuation is during this period up to only about 19.
The resulting beer is dark brown, extremely rich (but here also partly arises from not broken down glucose) and sweet - the smell is pleasant (which is probably a consequence of the extremely slow fermentation). It is not possible to drink much Joppenbier - it is full-bodied, extremely suitable for mixing with other beer and is also for such purpose exported to England.
The clear beer can be left a year in the vat on the yeast without being damaged - of course, however, the degree of attenuation will increase."
"Schule der Bierbrauerei" by G.E. Habich, published in 1865, pages 402 and 403.
I'm assuming the gravities mentioned are Balling. That makes the OG about 1196 and the FG 1076. Even more than the craziest Scotch Ale. The hopping rate, at only about half a kilo per Zentner malt (or per hectolitre beer), is very low. About the same as Berliner Weisse, which usually has no hop character at all. My guess is that Joppenbier tasted pretty malty.
How Joppenbier relates to Jopen Bier, I'm not sure. The latter was an early type of hopped beer, which, if I recall correctly, originated in Hamburg. There is currently a version of Jopen Bier brewed for the Dutch market in Belgium.
Here's confirmation that most Joppenbier (or Jopenbier) was exported to Britain:
"Danzig. The demand for Jopenbier was very limited, as in the English manufacturing distrcts, the main sales locations for this article, most workers were unemployed because of the American war. The sale price was 70 fr. per 1/4 T. free on board. Manutactured were 22300, exported 24300 1/4-T. Value of 56700 Th; of the shipped amount a great part was sent to England on credit and stored there unsold. The stock at year-end was 8000 1/4-T.""Preussische Statistik" 1863, page 101.
Tomoorrow much more about Dantzig Black Beer. Much, much more. Really.