The Professor: Cheers to Frozen Alcohol Treats
A new process allows alcohol to be frozen at household freezer temps
The art of freezing products containing edible alcohol (ethanol) at the temperatures found in common household and commercial freezers has been unsuccessfully attempted for many years. Even attempts at diluting the alcohol with a water solution have produced a watered-down product that still needs temperatures near minus 20°F to freeze the solution solid.
But humans do not give up easily when it comes to finding new ways to enjoy alcohol.
A company has invented and patented a method for freezing edible alcohol products. The consistency of the products ranges from hard and solid through sorbet-like, and all stay frozen in the temperature range of 24°-28° without affecting taste, consistency, or alcohol content. This process can now be accomplished with regular household refrigeration.
Some of the edible products have a rubbery, solid consistency at room temperature, so the same patented process can also produce a gummy-type product with no freezing required. The product may even be thawed and then refrozen, allowing for the final product to be frozen during the point of sale rather than necessitating cooling during shipping. The products have shelf lives of about 18 months without the addition of a preservative and longer with a preservative. Shelf lives of each product will depend on the concentration of the preservative within the product, and only the state of matter is changed with the addition of food additives.
Whether frozen or thawed, the final product will always retain the taste and flavor of the initial alcoholic beverage. This phenomenon happens because once back to its melting temperature, the alcohol immediately reverts to its natural form.
This technology allows a person control of the alcohol content, freezing temperature, and consistency of the final product. Companies can now create a line of frozen alcohol products, such as ice pops, gummy bears, slushes, ice cream, desserts, bubble gum, drink mixers, and ice cubes that don’t dilute mixed drinks. Producers of alcoholic beverages may increase their brand strength by introducing a frozen version of their product, particularly the increasing popular flavored alcoholic beverages.
FREEZING POINT DEPRESSION
Ethanol is produced in the process of fermentation, just like wine, beer, whiskey, and other liquors are made. Ethanol is a colorless, volatile liquid and is the intoxicating agent in liquors. Ethanol is often referred to as “ethyl alcohol” or “grain alcohol.” Ethyl alcohol’s chemical formula is C2H5OH. Pure ethanol has a molecular weight higher than that of water and freezes at a much lower temperature. It freezes at a lower temperature because hydrogen bonds do not play as important a role in the interactions among the ethanol molecules as they do in water. Pure water freezes at 32° at standard atmospheric pressure. However, when ethanol is added to water, the freezing point of the water will be depressed or lowered — instead of freezing at 32°, a water/ethanol mixture will freeze at a much lower temperature.
The refrigeration and air conditioning industry has used this same phenomenon for many years in chiller system brines that are circulated as secondary refrigerants to keep them from freezing and turning solid while in circulation. Another example of freezing point depression is adding a salt solution to roads in the winter season to depress (lower) the freezing point of water and prevent ice formation. The antifreeze in a motor vehicle’s cooling system is another example.
FREEZING POINT ELEVATION
Additives can also be used to elevate solutions’ freezing points. The phenomenon of ethanol freezing at such low temperatures can be reversed by the addition of food additives that introduce a chemical reaction with the water and/or ethanol. It was discovered that this added chemical reaction will cause the solution to freeze at higher temperatures despite the presence of ethanol. The process lowers the mobility of the free alcohol molecules in a solution, which make it more susceptible to freezing.
This process also introduces some “molecular order,” which lowers the entropy of the system. Entropy is often defined as a degree of disorder or randomness in a system. It is also a thermodynamic quality representing the unavailability of a system’s thermal energy for conversion into mechanical work. The higher the entropy, the higher the degree of disorder. Less thermal energy is thus available to be converted into mechanical work.
One of the food additives used in the ethanol freezing process is a gelling agent named “agar,” which is commercially extracted from the cell membrane of algae. Agar, by itself, is insoluble in ethanol. However, its use in alcohol freezing is limited to its solubility in water to form a gelling solution. Once agar is introduced into the ethanol, the solution is then mixed with alcoholic beverages to be frozen. When adding agar in large amounts, the resulting solution is a gummy-type product. Sugars, edible acids, and other additives may be added to this mixture. Thus, the consistency is not that of a frozen product, but rather that of a rubbery product. However, when consumed, the alcohol effect is felt in the mouth.
Another aspect of alcohol freezing at reasonable household freezer temperatures includes purifying water to a certain conductivity level. The more pure the water is, the less it will conduct electricity. Believe it or not, pure water is a poor conductor of electricity. For purposes of freezing, once water is purified, it is heated and agar or another gelatin is dissolved in the solution while it is vigorously stirred. After several additions of agar, sodium metabisulfite and alcohol are added to the solution. After being cooled and left to stand for at least four hours, the mixture will then freeze at 24.8°. The lower the temperature, the more solid the product will become.
Publication date: 11/7/2016