French chemist Louis Pasteur was the first zymologist when in 1857 he connected yeast to fermentation. Pasteur originally defined fermentation as "respiration without air".
Pasteur performed careful research and concluded:
The German Eduard Buchner, winner of the 1907 Nobel Prize in chemistry, later determined that fermentation was actually caused by a yeast secretion, which he termed zymase.
The research efforts undertaken by the Danish Carlsberg scientists greatly accelerated understanding of yeast and brewing. The Carlsberg scientists are generally acknowledged as having jump-started the entire field of molecular biology.