Mehlschwalbe is a mixed fermentation sour beer with coffee from roasteries in Vienna. Our approach to brewing sour beer leans heavily on the Belgian lambic tradition. We produce a wort from malted barley, wheat and aged hops that is full of long chain carbohydrates (including starch) that ensure a long and slow fermentation. The fermentation takes place in an oak barrel that previously housed red wine. Our microbial culture consists of yeast and bacteria from Belgian lambic. The beer is allowed to slowly ferment for over a year, at which point we add coffee beans. After letting the beans infuse for a few days, we bottle the beer with a bit of sugar to ensure nice carbonation. The name Mehlschwalbe is German for house martin, a swallow that migrates to Austria from Africa for breeding. In summer, these birds build their nests on the outside of our barrel aging cellar.