The production of alcohol from sugar by yeast is an industry in its own right. A wine that is carefully produced using sterile equipment and fermented to 13% by volume will just about resist further infection from external organisms once that ferment has completed. The time during the fermentation of the must is when the must is most vulnerable to infection. The naturally produced fermentation-grade alcohol may be concentrated by distillation.
Denatured alcohol is a mixture of ethanol (ethyl alcohol) with a denaturing agent. To prevent alcohol intended to be used for purposes other than oral ingestion, many countries, require that denaturants be added to alcohol. The denaturant makes the alcohol taste bad. When a denaturant is added to alcohol it is called denatured alcohol or Alcohol Denat (Alcohol Denat. is the general name used for denatured alcohol). The denaturant present in the alcohol is not natural and there is need to return to quassin, the bitter substance present in Quassia (Picrasma excelsa), which used to be acceptable as a denaturant (brucine and brucine sulphate are also bitter alkaloid compounds obtained from plants).
The naturally produced fermentation-grade alcohol concentrated by distillation is used as a natural preservative in toners, aftershaves and colognes. Alcohol at a level of 15% is effective, but 20% is more assured. It is used also in other product types including makeup, fragrance, oral care, facial care, body care, and hair care products. Besides antimicrobial activity, it also has antifoaming, astringent, masking and viscosity controlling activities. It is also used as a solvent.
The safety of Alcohol Denat., Alcohol 3-A, SD Alcohol 30, SD Alcohol 39, SD Alcohol 39-B, SD Alcohol 39-C, SD Alcohol 40, SD Alcohol 40-B, SD Alcohol 40-C, as well as the denaturants Denatonium Benzoate, Quassin, Brucine and Brucine Sulphate has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The safety of other denaturants such as t-Butyl Alcohol, Diethyl Phthalate and Methyl Alcohol were reviewed by the CIR Expert Panel in other reports and found safe for use. The CIR Expert Panel evaluated the scientific data and concluded that Alcohol Denat., SD Alcohol 3-A, SD Alcohol 30, SD Alcohol 39-B, SD Alcohol 39-C, SD Alcohol 40-B, and SD Alcohol 40-C denatured with t-Butyl Alcohol, Denatonium Benzoate, Diethyl Phthalate, or Methyl Alcohol were safe for use in cosmetic products. The data were also considered sufficient to support the safety of Denatonium Benzoate when used as a denaturant. The CIR Expert Panel also concluded that the data were insufficient to support the safety Quassin, Brucine and Brucine Sulphate as denaturants, and Alcohol denatured with these denaturants.
Ethanol is considered broadly toxic and linked to birth defects following excessive oral ingestion. Potential risks from ethanol in personal care products are significantly smaller than the health risks posed by the consumption of alcohol.