Created as a kind of random product, its origin is in the stables of the local farmers. Curious about the reason why oak beams and boulders stained so quickly and became so dark, it was investigated and found that the urine of horses and the gases of the cattle contain ammonia, which reacts with the tannic acid of the oak. The result is a dark, almost black wood.
Today, the chemical reaction from the cowshed is solved by technical means, of course: by treating the oak with ammonia, its wood assumes a brown, dark-brown to black hue. Its saturation, in turn, depends on the amount of tannic acid contained in the native oak. In addition, the reaction of the ammonia or ammonium chloride with the constituent parts of the wood forms age- and light-stable complex organic salts that make the wood more supple and at the same time more resistant and gives innovative German interior designers another fascinating method of surface refinement.