It seems that towardst the end of the 19th century some North German top-fermenting breweries started to brew beers using methods similar to bottom-fermenting breweries. Presumably to try and stave off competition from Lager. As both Altbier and Kölsch still exist, you could say that the attempt was successful.
Düsseldorfer, Kölner, Wachholder beers. (The latter is a stimulus for bacteria).
Original gravity: 8-9% Balling. Either an infusion or decoction mashing method can be used. These bitter beers should be gold-coloured, and are often produced by the method of "mixed production" (see page 57).
Pitching temperature; 8° R [10º C] Fermentation: 6-7 days.
It is pumped after a good break, fermented at 5° R [6.25º C] in large storage casks, and is cleared with wood chips. After sufficient bunging these beers are usually clear. - In the case of Bitterbiers, the break only occurs when cold, as the protein goes into the yeast head. - In order to produce the strong hop flavour, a large amount of hops are added to the wort in the brewing house, and also in the lager barrel of boiled hops together with the water they were boiled in is added.
Since the yeast quickly degenerates, the old yeasts of the main production are usually used.
The treatment and character are very similar to bottom-fermented beer; it also served in a similar way.
If these beers were less bitter, they might sell more outside the production area. On the other hand, the heaving hopping gives them a long shelf life."
"Die Fabrikation obergäriger Biere in Praxis und Theorie" by Braumeister Grenell, 1907, pages 77 - 78.
The OG Grenell specifies looks a bit low to me. I’d expect a Lagerbier to be a minimum of 12º Balling.
Though Kölsch is a golden colour, I don’t think anyone would say that of modern Alt. So has Alt become darker over time, or was it always more of an amber colour and Grenell just got it wrong?
The primary fermentation temperature of 10º C is pretty cool for a top-fermenting yeast. I guess you’re going to get a pretty clean beer with few esters at that temperature. Though the lagering temperature looks higher than for a bottom-fermenting beer, which would start a 5º C and then drop to -1º C or so.
It’s the hopping I find most intriguing. They’re clearly doing a type of dry-hopping in the lagering vessel, though they’re using boiled rather than raw hops.
I love the final comment about how the beer would sell better if it weren’t so bitter.