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 (eg: 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 ( eg: extracting the desired flavors from a blend of alcohol,herbs,fruit without heating the mixture up).
It is possible to create two completely different products from one technique and a single ingredient. Obtain essential oils that can be used to infuse or intensify flavor without affecting texture or composition of your creation
|Image and source courtesy Polyscience|
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.
While most chefs are familiar with regular distillation process, this technology adds another dimension: it works under reduced pressure, which lowers the boiling point to as low as 95°F/35°C. By remaining at such low temperatures, valuable flavor compounds are preserved and will add to complexity of the result.
At Alinea Restaurant in Chicago the rotary evaporator is used to extract herb aromas like basil. Another innovative application by Alinea is to distill the pure chili’s essence. During that process the chemical capsaicin, responsible for the heat, is left behind. A unique flavor experience is guaranteed.