Temperature Unit for Dipropylene Glycol Heat Resistance

The temperature unit referred to for the heat resistance of Dipropylene glycol, where it states "Do not heat more than 80 degrees," is degrees Celsius (°C).

In cosmetic and chemical formulation contexts, temperatures are typically given in Celsius unless otherwise specified.

When adding Dipropylene glycol (often used as a solvent for fragrance oils) to your melt and pour soap base, it is best practice to add it when the soap base has cooled down significantly after melting. Adding fragrance and solvents at high temperatures can cause the fragrance to degrade or evaporate quickly.

Aim to add your mixture of Fragrance oil and Dipropylene glycol when the melt and pour soap base is around 50-60°C (120-140°F), or ideally closer to the flash point of your specific fragrance oil if known, ensuring it is well below the 80°C maximum for Dipropylene glycol and also below the point where the fragrance could be damaged by heat.