Barth and Schanderl used large, pressure-resistant iron containers to produce clear beer. Fully fermented beer from the tuns is mixed with young beer and undergoes a secondary conditioning.
5-10% young beer is added. The container has a safety valve that opens when the pressure inside exceeds 3 atmospheres. This usually happens after a few days secondary conditioning as the proportion of young beer is quite high and the temperature is 12.5-15º C.
Barth adds wood chips to the container to help clarification. Schanderl doesn't use any clarifying agent, but after 3-4 weeks uses the pressure in the container to force the beer through a filter and into wooden transport casks.
The landlord transfers the beer under pressure from the transport cask to a glass container which is connected to the tap from which drinking glasses are filled with beer.
Recently it's become possible to move the beer under pressure into drinking glasses directly from the transport barrel.
During the early days of producing yeast-free Weissbier, the process often made the beer turn a darker colour or even purple. This was the result of the lactic acid acting on the untreated iron container which release iron which combined either with tannin from the hops of from the untreated oak transport barrels.
The problem of discolouration was solved by treating the iron container with paraffin.
Another hindrance to the spread of yeast-free Weissbier was its low CO2 content when served. This was solved by improving the serving apparatus and simplifying the pipes from the barrel to the tap. This enables such beer to more closely resemble bottle-ripened weissbier in flavour.
Yeast-free Weissbier has a longer shelf-life because:
- it's free of all organisms
- no water is added
- the high CO2 pressure restricts the growth of bacteria
Hopefully yeast-free Weissbier will become more common and become a people's drink [Volksgetränk] like bottled Weissbier.
Sunday, 4 May 2008
Berliner Weisse the long version (part 9)
Almost finished with Berliner Weisse. At least the stuff from "Die Herstellung Obergähriger Biere". I've got other sources. Just let me know when you get totally bored. It won't make me stop, but I will have the satisfaction of knowing I'm doing my job right.