What Is Rotary Evaporator Cooking?
A rotary evaporator is a laboratory apparatus used to separate a mixture into its various components depending on their volatilities. This is achieved through evaporation and condensation. Rotary evaporator cooking is the process of home-based cooking using a rotary evaporator to separate food substances and flavors, as well as concentrating food flavors and aroma.
The rotary evaporator is used mainly for two cooking purposes: to concentrate the non-volatile constituents in a food mixture, and to extract the volatile flavors and aroma constituents from a food mixture. A rotary evaporator is an ideal distillation apparatus different from other conventional distillation apparatus, as it is capable of separating food components from one another without affecting any of the food components. This makes it ideal and more popular for home cooking.
The versatility of the rotatory evaporator over other distillation apparatus is based on two main components of the rotavap: vacuum evaporation, which allows evaporation of components at low temperatures, and the rotation of the evaporating flask, that increases the surface area for evaporation as well as enhancing forced convection thereby allowing even mixing and stable evaporation.
The Benefits of Rotary Evaporator Cooking
1. A rotary evaporator consists of a vacuum pump responsible for creating a vacuum evaporating condition, which ensures all the evaporation is successfully finished under a lower boiling point. This ensures that the original performance of the food material is maintained as well as efficient and accurate evaporation is achieved without the need for a very high-temperature source.
2. The heating source of a rotary evaporator is a heated water bath or oil bath. Heating involves immersing the evaporating flask into the hot bath. This increases the surface area of the mixture thereby increasing the rate of distillation.
3. Another benefit of using a rotary evaporator for kitchen cooking is the rotating feature of the evaporation flask. This also helps in increasing the surface area for evaporation hence a faster rate of evaporation. The idea behind rotation is that behind the rotation is the creation of new surface area per unit time, hence the higher the rotation per minute the higher the rate of evaporation.
4. A general benefit attributed to rotary evaporation cooking is the gentle and precise cooking of fresh food while maintaining the taste, aroma, and nutritional value of the food.
5. Rotary evaporator cooking allows visual monitor and adjustment. A rotary evaporator consists of transparent glass hardware, hence easy cooking visualization. This allows the user to visually see the completion of the evaporation, eliminating the guesswork.
6. A rotary evaporator also consists of a totally sealed glass hardware, this ensures that no wastage or leakage of the mixture as well as the distillate. thereby ensuring 100% component recovery.
7. Rotary evaporator cooking involves the use of evaporation and distillation at lower temperatures to achieve the desired cooking purpose. The two processes used, together with low temperatures make rotovap cooking safe and beneficial for human consumption.
How to Cook With A Rotary Evaporator At Home?
Cooking with a rotary evaporator involves understanding the working principle of a rotary evaporator, how to set up the rotary evaporator, and the function of the main parts of the rotary evaporator.
The main parts of a rotary evaporator and functions.
1. Rotary motor.
A rotary evaporator consists of an electric-powered motor that plays an important role by rotating the evaporation flask at a continuous and constant speed. This results in an increased surface area for evaporation as well as even mixing, heating hence a stable and even evaporation.
2. Vacuum source.
This is the system responsible for creating a vacuum within the airtight set-up, thereby reducing the pressure within the system. The vacuum source can be simply a water aspirator consisting of a water immersed trap, or a complex mechanical vacuum pump consisting of a refrigerated trap.
3. Glass tube.
The glass tube has two functions, the first is to protect and support the sample during rotation while the second is to help in the creation of a vacuum.
4. Heating bath.
The mainly used heating bath is a hot water bath. The function of the heating pot is to heat the sample and help in temperature regulation.
It is mainly found in a double snake shape and the function is to condensate the evaporated sample as well as enhance convenient sample collection.
6 Receiving flask.
The function of the collecting flask is to receive the distilled sample.
Modern rotary evaporators also consist of a digitalized system with digital display for temperature and rotation speed, vapor temperature sensor, and digital vacuum control.
How to set up a rotary evaporator?
1. The first step is to make sure you have all the apparatus in good working condition, clean and dry.
2. Set the water bath at the desired temperature.
3. Set up the condenser and connect it to the cooling water source. Allow the water to flow gently.
4. Fill the evaporating flask with the solution/mixture to be evaporated. Fix the flask to the evaporator’s bump trap and sealed with a clip. For the liquid-liquid mixture, you can connect the flask first and suck the solution through the product in/air vent.
5. Adjust the flask position and immerse it partially into the water bath using the joystick knob.
6. Switch on the vacuum source.
7. Switch the rotation on and set at your preferred speed using the rotation notch.
8. Close the stopcock on the evaporator. Make sure the solution does not boil vigorously if that happens, open the stopcock. Always make sure that the solution is stable.
9. Leave the solution to evaporate.
10. After the evaporation has completed, raise the evaporating flask out of the water bath. Hold the flask with your right hand and open the stopcock with your left hand.
11. Remove the evaporating flask to obtain the residue and collect the distillate from the receiving flask.
12. Switch off the vacuum source, the condenser, and the water bath.
The basic working principle of rotary evaporators for cooking.
After knowing the main parts and their functions, now you can easily understand how does a rotary evaporator work, which generally involves evaporation and condensation.
The evaporation flask consisting of the raw mixture is heated by the water/oil bath as it rotates continuously until all the evaporation has taken place or as desired. Then, the vapor travels through the airtight system to the condenser, consisting of the cooling coils. Here the vapor is chilled and condensed back to a liquid that flows to the receiving flask, completing the cooking process.
Applications of rotary evaporator cooking.
1. It is used in modern kitchens to concentrate blood orange flavors by removing water, obtaining the purest and freshest flavors.
2. It is also used in the extraction of different flavors of interest, from blended herbs, alcohol, and fruits at very low temperatures.
3. Rotary evaporator cooking is also used for the separation of acids, sugars, colors, and bitter compounds from alcohols, flavor molecules, aromas among others.
4. It is also used to cook homemade aquavit and chocolate liquor by mixing chocolate liquid and vodka.
5. It is used for the extraction of herb aromas like basil, at Alinea Restaurant in Chicago.