Organic compound (lat. Urea) that should not be confused with uric acid. It is used by many animals as the end product of the metabolism of nitrogen compounds such as amino acids and proteins are produced and excreted in the urine. Pure urea is a white, crystalline, non-toxic and hygienically safe solid that smells slightly of ammonia. The urea was discovered in 1773 and was the first organic compound to be synthetically produced for the first time in 1828. This revolutionary invention contradicted the doctrine of the time that organic substances can only be produced by the so-called "vis vitalis" (vital force) and was the beginning of organic chemistry.
The urea, also known as carbonic acid diamide, is a so-called amide as well as calcium cyanamide fertilizer because he nitrogen in amide form (salts of ammonia). Due to its high nitrogen content of almost 50%, it is the most important nitrogen fertilizer used in viticulture worldwide. Urea can be found in the fermentation in small quantities also get into the wine, where it can be used in the longer term ethanol to ethyl carbamate responding. This substance is suspected of being carcinogenic in humans. If the amount of urea in wines intended for prolonged storage exceeds 1 mg / l, the enzyme can urease the urea in ammonia and carbon dioxide split and thus reduced.