At Black Project, all of our releases fall into one of two categories. Every beer will say either "spontaneous" or "wild" on the label. Our perspective on what these terms mean may be a bit different than other breweries, so I decided to make a post sharing what we intend with each term.
"What is a spontaneous ale?"
At Black Project, spontaneous ales are beers made without adding any cultured yeast or other microbes whatsoever. The entire fermentation happens because we expose the beer to small numbers of wild microbes from the air in our coolship (or potentially from, say, fruit skins).
These first cells eventually multiply and the many different species represented ferment the wort into beer that has incredible complexity and flavor. These beers are typically tart to sour with moderate level of funkiness and fruit. However, because we have very little control over the organisms making these beers, their characteristics can potentially very over a wide range.
There is considerable risk in making these types of beer. A percentage of the beers will not develop favorably, or not develop at all - and have to be dumped. They also take a minimum of several months to mature, often times a year or more. Finally, because of the unknown nature of the fermentation organisms - spontaneous ales that we release can never really be repeated. Luckily, with our spontaneous beers, repeatability isn't one of our goals - we like to let nature take its course.
"What is a wild ale?"
Many brewers, journalists, and craft beer enthusiasts use the term "wild ale" to describe any beer made with Brettanomyces. Almost always, when a brewery uses the term wild, they are talking about a beer made with Brettanomyces that they have purchased from a lab. The strains they use are essentially available to anyone with a Mastercard, typically a strain isolated from Belgian beer. There are 5-10 of these strains currently on the market.
We DON'T use any commercially available Brettanomyces (or any other type of yeast or bacteria that is commercially available) in any of our beer. There isn't anything wrong with these strains, necessarily. However, we feel the diversity of our local microflora is superior in many ways, not the least of which is that all of our wild strains were "caught" by us personally.
When we use the term "wild" it means that the beer was made using cultured (grown) wild yeast and/or bacteria from our local environment. We may grown these microbes in another beer/barrel (aka inoculation via blending) or we may isolate wild microbes and grown them as pure cultures to use alone or, much more typically, in a blend with other strains.
Wild ales will vary much less batch-to-batch than spontaneous ales, and will also be able to be released on a much more consistent schedule. This means that our wild releases will be much less limited than our spontaneous ales. In 2015 we intend to release at least one wild ale that will be available year round.