Organic compound (Latin urea), which must 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 produced and excreted in the urine. Pure urea is a white, crystalline, slightly ammonia-smelling, non-toxic and hygienically safe solid. The urea was discovered in 1773 and was the first organic compound, which was then produced in 1828 for the first time synthetically. This revolutionary invention contradicted the former belief that organic substances could only be produced by the so-called "vis vitalis" (life force) and was the beginning of organic chemistry.
The urea, also known as carbonic acid diamide, is a so-called amide in addition to calcium cyanamide fertilizer because he nitrogen in amide form (salts of ammonia). Due to its high nitrogen content of almost 50%, it is the world's most important nitrogen fertilizer used in viticulture. Urea may be at the fermentation in small quantities also enter the wine, where he long term with ethanol to ethyl carbamate responding. This substance is suspected to be carcinogenic in humans. If the amount of urea exceeds 1 mg / l for wines intended for longer storage, the enzyme may be used urease the urea in ammonia and carbon dioxide split and thus reduced.