The flash freeze plate is simply a restaurant (or home) appliance that generates a freezer temperature on the top plate of the unit.  Most units go from on to flash freeze in 10-15 minutes.  Once at freezer temperatures, the unit can remain on for as long as needed.  The simple process is to place food items on the surface where they freeze.  The gastronomy aspect of this is to use the ingredients and physical shape of the food and freeze it.  Layers can be made.  Ice cream can be mixed and rolled.

Hazards: none outside of the normal 42-134F temperature danger zone.  The fact that these units are designed for “flash” freezing implies that the cooling below 42F will occur quickly.  So, like normal non-special processes, the handling of the food before freezing must remain safe.  If a chef were to rotate flash freezing between raw foods and ready-to-eat foods, there could be cross-contamination.  However, if the items are frozen on parchment, then this is less of a concern.

Controls: Follow standard food code food processing controls: minimize 42-135F to ≤ 2h, and describe your method to prevent cross contamination.

Special Process or not?  No, this is not a special process, since controls are all typical for regular food processing at retail.  This can be considered another piece of kitchen equipment like a blender.

In the simplest of terms, it is applying chemistry to foods.  The deeper explanation is examining the science of traditional foods and cooking, then using that science in new ways.  From the food safety professional’s view, new can mean new hazards that need new controls.  Let’s start with a list and brief explanation of some molecular gastronomy foods and processes.

  1. Dehydrating (warm or hot)
  2. Freeze drying – once relegated to large food manufacturers, at least one company now produces a less expensive and smaller unit that can be used in restaurants.
  3. Liquid nitrogen freezing of foods or adding liquid nitrogen to foods or beverages
  4. Freezing plates.  e.g. the anti-griddle – a new appliance that has a frozen surface to freeze foods quickly
  5. Spherification – think boba (tapioca balls); but instead, these have centers of almost any liquid or puree (savory or sweet).  AKA faux caviar.
  6. Transglutaminase – aka “meat glue
  7. Hydrocolloid use – gels, starches, pectins, and gums are all used by the food industry.  Now restaurants are doing the same.
  8. Black garlic – thermal caramelization turning garlic into “candy”
  9. Edible paper and ink.  If it says, “food grade” or edible” it should be safe.  See an FDA warning.
  10. Distillation – Rotovap equipment
  11. Supplements as ingredients (CBD’s, etc).
  12. Smells for success – terpenes and other aroma additives
  13. The FDA “Everything added to Foods” List. May help determine if an additive is safe in foods.

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).