Method for the program control of a pan

A method of controlling the consistency of massecuite obtained from a first starting material having a specific number of solute molecules per unit volume in a batch process during automatic boiling in a pan using a rheometer for measuring the consistency, said method comprising the steps of

• boiling said massecuite in said pan;
• measuring the consistency of said massacuite using said rheometer;
• and
• supplying water or syrup solution to said pan only when the consistency measured by said rheometer is between an ideal value of consistency and an allowable value of consistency, both said ideal value and said allowable value being determined by germ growth calculated using the following formula:
• ##EQU4## wherein n.sub.c is number of germs which grow in a unit time, m is mass of a solute molecule,
• .pi. is a constant, k is Boltzmann's constant, T is absolute temperature, x.sub.c is the distance between peak values of gravity between solute molecules v is the average velocity of movement of solute and solvent molecules, A is a constant of about 0.4, C is the upper limit of speed at which molecules are caught by crystals, and E.sub.c is the gravity at distance x.sub.c in the interaction of grains;
• and
• wherein for calculating said ideal value of consistency, N is said specific number of solute molecules per unit of said first starting material;
• and
• wherein for calculating said allowable value of consistency, N is the number of solute molecules per unit volume of a second starting material having massecuite of an acceptable lesser purity and being smaller than said specific number of said first starting material.