In both traditional chemistry labs and culinary technology labs, the rotary evaporator, or rotovap, is an instrument used to distil a solvent or to concentrate food essences. Rotovap cocktails are becoming very popular in bars and restaurants because the deliate fruit or herbal flavours become very intense when concentrated by rotary evaporation.
This blog is a resource for the latter using the rotary evaporator as part of the process for making unique cocktail flavourings and essences.
Concentration of flavours – To concentrate non-volatile components in a mixture (for example, concentrating the purest and freshest flavours from a blood orange by removing the water)
Flavour creation – Extract the volatile aroma and flavour molecules from mixtures gently and at low temperatures (for example, extracting the desired flavours from a blend of alcohol, herbs, and fruit without heating the mixture up).
The key in distillation is to remember that it is a separation. Sugars, acids, colours, and most bitter compounds are separated from aromas, alcohols, water, and small flavour molecules, etc.
What is phenomenal about rotovap distillation, is that it can separate food compounds from one another without altering them.
Focus on products:
Rotary evaporator – KNF system
A typical rotary evaporator has a water/oil bath that can be heated. This keeps the solvent from freezing during the evaporation process. The solvent is removed under vacuum, is trapped by a condenser and is collected for easy reuse or disposal.
Typical set-up for cocktail mixology involves:
RC600 Rotary Evaporator with splash-proof keypad control and standard plastic coated glassware (a 3L flask is essential )
SC920G Fully automatic speed regulated vacuum system with wireless remote control – 20l/min <2mbar. Lowering the pressure allows the alcoholic liquids to be distilled at lower temperatures to retain the delicate flavours desired.
C900 Chiller 230V 50Hz (Working temperature range (°C) -10 to +40)
The chiller is generally filled with water, but to reach temperatures below 0°C, a coolant is required and in the food industry, a food safe coolant is required like coolflow from hydratech.
So if you visit a well known hotel bar in the centre of London you might just spot the rotary evaporator working its magic to produce delicious unique flavourings for cocktails.