Krausening in an open fermenter? (!)

This recipe for dampfbier calls for krausening, and it says:


What would be the purpose of krausening in an open carboy? Or am I misreading the recipe?

By "unpressurized" I don't think they mean "open", just that its got an airlock that is allowed to vent at regular pressure. They suggest one option is to ferment the krausen in a corny keg as a secondary under 7-8psi (presumably with some sort of pressure relief valve installed), but if you don't do that then you can do it in an unpressurized carboy, which would just have an airlock installed. I'm curious as to what the proposed effects of fermenting under pressure for this secondary would do, but I think the option you're talking about would just involve racking over to a secondary fermenter, adding the krausen wort, and sticking an airlock on it to ferment the krausen.

On an off-topic note, have you figured out why they suggest krausening in this way? I've always thought of krausening as a way to carbonate the beer (by adding back unfermented wort rather than sugar/DME), but with this it sounds like they're just looking for a quick secondary fermentation. If it was done in a corny keg it would also serve to carbonate it to 7-8psi, but not sure why you'd still need to do that if you were allowing the CO2 to release in a carboy. Maybe another quick secondary fermentation helps to clean up some off flavors?

What they are calling krausen isn't krausen. Krausen is actively fermenting wort added to the fermented "still" beer for carbonation. They should have used the term speise, which is just wort without yeast added to it. Kind of like priming with dme mixed with water. All they're saying is you can use a corny with a priming solution and carb in the corny. Or, you can mix the priming solution with the beer in some kind of a container, then bottle it and let it carb in the bottle.

Right, I meant unpressurized carboy. I have to figure this extra wort addition (speise) is to help carbonate the beer and would not serve any purpose in an upressurized vessel. I don't keg, so I guess I'll skip that step, though I might use the speise before bottling for carbonation. Thanks for the help!