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