What peculiarities are involved in ingredients extraction for blended alcohol and beer?

Beer, wine, and other alcoholic drinks laced with distinctive flavors are in great demand at present. The alcohol market is also witnessing a shift towards low alcohol products such as low alcohol beer or even no alcohol beer. This presents a peculiar challenge before brewers in that they have to retain or add specific flavors in the blended alcohol and blended beer, while doing away with the undesirables.

Now, carbon dioxide (CO2) supercritical fluid extraction (SCFE) is a process endowed with selectivity – it can extract the target molecule in its relatively pure form while leaving the other ingredients largely untouched. Exactly why the process is used for extraction of alcohol flavors.

Take the case of wine for example. Wines are a complex mixture of more than 800 volatile compounds. Removing the molecules that make up the alcohol content of the wine while retaining the other compounds calls for a high level of selectivity, something that the CO2 SCFE process is well capable of delivering. Retention of other compounds is necessary because they provide the required flavor, aroma, and texture to the wine – elements that make customers demand it.

Similarly for beer. The beer industry uses the CO2 SCFE process in two steps for the extraction of aromatic or essential oils in a highly concentrated form. These oils provide the necessary flavor to beer. The CO2 SCFE process serves another purpose in the beer industry. By sustaining the integrity of the hop flavor for a longer period of time, the process boosts the shelf life of beer.

Furthermore, because the CO2 SCFE process has an operating temperature close to the room temperature, it does not thermally distort the flavor. If at all, such distortion is at a bare minimum level. Hop is the plant from which the characteristic bitter tasting flavor is derived. The flavor also acts as a natural preservative.

The reason why the CO2 SCFE process is able to provide such a high degree of selective extraction lies in its very nature. It uses supercritical carbon dioxide (sCO2) as the supercritical fluid. A supercritical fluid is at a pressure and temperature respectively above its critical pressure and temperature. In this state, the fluid exhibits properties that can be similar to liquids, or gases, or both.

For example, density of such fluids is high as that of liquids, imparting greater solvent power. Viscosity and surface tension of the fluid is low, which enables it to penetrate deeper into porous solids for greater extraction efficiency. 

Importantly, the solvent power of a supercritical fluid can be changed by altering pressure. By controlling the pressure, the fluid can be tuned to extract one particular type of molecule while leaving other molecules largely undisturbed. Two different molecules can also be extracted from the same raw material at two distinct pressures.

 Extraction occurs in extractors at high pressure when the solvent power of the supercritical fluid is high. In the separator, which operates at low pressure, the extracted molecule comes out of the fluid and is collected. At low pressure, the solvent power of the fluid is lesser.