There are not too many sour stout based beers out there. But now Barrelworks from Firestone Walker is adding a dark sour to their range. Here is the backstory on this new beer “…Velvet Merkin which was then given our treatment and transferred to French, American and Hungarian oak barrels thus transforming one amazing beer into something inconceivable. Mordred offers a depth of dark chocolates, espresso and spices of nutmeg and clove.”