Lambic beer is a variety of spontaneously fermented sour beer native to the Senne valley in Belgium. Generally, even before Pasteur provided a microbiological perspective, brewers have strived for a 'clean' Saccharomyces fermentation, while lambic brewers have allowed their beer to be fermented, soured, and enhanced by a wide variety of native airborne microbes, including Saccharomyces, Brettanomyces, Lactobacillus, and Pediococcus. It is an anomaly among beers; it embraces and is defined by the same processes considered spoilage in other styles of beer. I would like to examine how lambic fermentation has been understood as opposed to 'clean' fermentation in both the pre- and post-Pasteurian understandings of fermentation.
In exploring the philosophy of lambic brewing, I will attempt to recreate several processes in lambic brewing. Initially, I will perform a lambic-style mash, which varies from conventional brewing methods in several ways, including intentional tannin extraction (to support the extended bacterial fermentation) and the use of a high proportion of unmalted wheat. I will boil five gallons of the resulting wort with intentionally staled hops, another lambic brewing method, but, rather than allowing the beer to cool and be inoculated in the open air, I will ferment it (with a keen sense of irony) using pure cultures of the predominant yeast and bacterial strains found in genuine Belgian lambics. This will provide a beer closely mirroring genuine, traditional lambics, and will allow me to observe in detail the various stages of lambic fermentation. (I might also be treated to the bafflement and skepticism of conventional brewers as I expose my roommates' brewing equipment to dreaded lacto and brett infections.)
The above experiment will provide the closest beer possible to a true lambic; it does not, however, mirror the philosophy of lambic fermentation. It uses pure cultures in a closed environment, more closely mimicking the methods of post-Pasteurian conventional brewers than lambic brewers of any stripe. Thus I have arrived at the second, more diabolical stage of my experiment. I will save a few litres of sterilised wort from my first lambic batch. When spring arrives, I will take this wort with me out of the city (where I'm unlikely to catch anything good with it), preferably to an orchard, place it in a broad, shallow pan (in the lambic style) overnight, and allow it to be inoculated with the Nova Scotia local blend of airborne microbes. On my return, I'll brew up another lambic-style wort, but this time I will mix it in with the spontaneously fermented starter culture. The resulting beer will be one made in accordance with the philosophy of lambic brewing.