How to use the eutectic point tester in freeze-drying experiments

During the pre freezing process of freeze-dried products, for the crystallization system, as the temperature decreases, ice nuclei are formed in the system when the freeze-dried product reaches below the freezing point. The ice nuclei gradually increase, and the concentration of solutes in the remaining solution gradually increases. Crystals precipitate when it reaches supersaturation, and the temperature continues to decrease until the remaining solution solidifies into a crystalline mixture of ice and solutes. At this point, the temperature is called the eutectic point, but for some substances, the eutectic point is not a specific temperature value, but a temperature range.