The Collaborative International Dictionary of English v.0.48:

Zymometer \Zy*mom"e*ter\, Zymosimeter \Zy`mo*sim"e*ter\, n. [Gr.
   ? ferment, or ? fermentation + -meter: cf. F.
   zymosim[`e]tre.]
   An instrument for ascertaining the degree of fermentation
   occasioned by the mixture of different liquids, and the
   degree of heat which they acquire in fermentation.
   [1913 Webster]