Evaluation of the Formgraph for Comparing Rennet Solutions

A new instrument for measuring milk clotting, the Formagraph, was evaluated. Measurement is movement of small pendulums immersed in linearly oscillating samples of coagulating milk. Pendulum movements are recorded on photographic paper, producing a diagram of firmness versus time. The instrument can be used for measuring milk-clotting enzyme activity in comparison to a standard, and in constrast to the rolling bottle method, it does not require continual observation. Coagulation times measured by the Formagraph are longer than those measured by the rolling bottle method, but both methods give linear standard curves between .2 and 1.0 rennet units/ml enzyme concentrations