Black Project is dedicated to spontaneous fermentation—no pitched cultures, no inoculated barrels, just 100 percent coolship-cooled wort and the airborne culture that then ferments the beer.
With many of their spontaneous beers conditioned on fruit, they add the fruit to finished beer so that refermentation occurs but the basic character of their spontaneously fermented, lambic-inspired beer remains in balance.
With grapes, however, they take full advantage of the wild microflora—wild yeast and bacteria—that live on the skins of grapes (the same microflora that winemakers have used for millenia to ferment wine). That microflora, together with whatever the wort picks up through their coolship, handles all the fermentation duties.