How do natural colors behave with heat and pH? Will they hold up in my process?

This is one of the most important practical questions to ask when working with natural colors, and the honest answer is that it depends on the specific pigment and your processing conditions.

On the heat side, natural colors are generally more sensitive than synthetic dyes. At very high temperatures — like the 290–300°F range used in caramel popcorn — some colors will shift or fade. Liquid formats may offer more flexibility in these applications, and adding the color later in the process can help preserve vibrancy. The result will typically be a softer, more pastel tone than you'd get from a synthetic dye under the same conditions. That's a characteristic of natural pigment chemistry, not a formulation error.

On the pH side, acidity and alkalinity can cause noticeable shade shifts, particularly in the purple and blue families. A purple derived from red radish will behave differently at low pH than one derived from purple carrot. Blue colors — particularly spirulina-based options — are sensitive to both heat and acidic conditions and can trend toward brown or green if the environment is too harsh. Testing in your specific matrix and at your intended pH is always the most reliable way to understand how a color will actually perform.