Mikkeller unleashes a new round of Spontaneous Series beers in 2013. Joining the series is SpontanPeach. The fruit is added to the base beer, a lambic fermented in oak.
Lambic, The Rundown.
A lambic is a spontaneously fermented beer. What’s that? The beer is exposed to wild yeasts and bacteria. In this case (most likely) these wild yeasts live in the oak of the barrels they are aged in. The result is a tart/sour tasting beer.