Evaporate

The rotary evaporator combines evaporation under vacuum and condensation (liquid-gas-liquid). This process is called distillation and the purpose is to separate a given mixture into its components based on their respective volatilities. It is explored by creative chefs for two main purposes:

• To concentrate non-volatile components in a mixture (for example, concentrating the purest and freshest flavors from a blood orange by removing the water)
• To extract the volatile aroma and flavor molecules from mixtures gently and at low temperatures (for example, extracting the desired flavors from a blend of alcohol, herbs, and fruit without heating the mixture up).

Compared to standard distillation processes, the significant difference of the technique with the PolyScience Culinary Rotary Evaporator Kit is the lower temperatures required for evaporation.

The key point to this technique is the gentle, precise, and efficient separation of food compounds without altering them. Two key components are responsible for this advantage compared to a regular distillation process:

• Liquids are evaporated under vacuum, which lowers their boiling point, eliminating the need for high-temperature distillation
• Rotation of the evaporating flask, immersed in a heated water bath, increases the surface area of the product, greatly speeding distillation and also, through forced convection, keeping the mixture evenly mixed to promote stable, even evaporation.

At Alinea Restaurant in Chicago this technique is frequently used to extract herb aromas like basil. Another innovative application by Alinea is to distill the pure essence of chilies. During that process the chemical capsaicin, responsible for the heat, is left behind. A unique flavor experience is guaranteed.