Molecular gastronomy combines artistic culinary experiences and passion with the scientific and technical foundations of food science. Freeze-drying various foods is one of the methods currently being explored by these cutting-edge chefs. Another is the rotary evaporation (concentration) of food essences.
The rotovap can be used for two purposes: 1) to concentrate non-volatile components in a mixture (e.g, concentrating flavors from a blood orange by removing the water), and 2) to extract the volatile aroma and flavor molecules from mixtures gently (e.g., extracting the desired flavors from a blend of alcohol, herbs, and fruit without heating the mixture up). The key to understanding any distillation is to remember that it is a separation. Sugars, acids, colors, and most bitter compounds are separated from aromas, alcohols, water, and small flavor molecules, etc.
Is this a “Special Process”? Are there food safety concerns?
Is this a “Special Process”? This question would hinge on the evaporation process itself. Are PHFs subjected to conditions that could permit the growth of pathogens? If yes. Then, yes, it’s a special process. What food safety concerns are there? (Biological hazards) Basically, it is a temperature danger zone question. If 42-134F for more than 2 hours, an operator would need to demonstrate why their specific process is safe. (Chemical hazards) Do no harm. The distilled chemicals must not be toxic at the concentrations the chef might use them at. Any legal concerns? Yes. It is not permitted in the USA to distill alcohol. The government fears it will not get its taxes. It is permitted to have a small rotovap. Some Chefs feel that if they use alcohol that has been purchased (tax paid), then they are meeting the spirit of the law. Also, there are some plant distillates that are not legally permitted in some states (examples are certain Hemp CBD derivatives).