Buying “pure” ethanol involves navigating the complex intersection of chemistry, taxation, and government regulation. Ethanol, also known as ethyl alcohol, is the intoxicating agent in alcoholic beverages. Chemically, “pure” ethanol does not mean a perfect 100% concentration because it forms an azeotrope with water—a mixture that boils at a constant temperature.
The highest concentration achievable through standard distillation is about 95% ethanol and 5% water, often labeled as 190 proof. To reach concentrations above 99%, called “absolute” or “anhydrous” ethanol (200 proof), specialized methods like molecular sieves are required. The availability of ethanol is primarily governed by whether it has been chemically altered to prevent human consumption, not its purity level.
The Difference Between Denatured and Undenatured Ethanol
The primary distinction in commercial availability is whether the ethanol has been denatured. Denatured ethanol is ethyl alcohol intentionally mixed with toxic or foul-tasting additives to make it unsuitable for drinking. This process renders the substance non-potable and dangerous to ingest, though it does not chemically alter the ethanol molecule.
Common denaturants include methanol or bittering agents like denatonium benzoate. The central purpose of denaturing is to exempt the product from the heavy federal excise taxes applied to beverage alcohol. Consequently, denatured alcohol is widely and cheaply available for industrial, cleaning, and solvent applications.
Undenatured ethanol, conversely, contains no intentionally added toxic substances. This grade is required for products meant for human contact, such as alcoholic beverages, food extracts, and pharmaceutical preparations. Because it is potable, undenatured ethanol is classified as beverage alcohol and is subject to strict government oversight and taxation.
The two main types of undenatured ethanol are high-proof grain alcohol, sold in liquor stores, and highly purified “food grade” or “USP grade” ethanol, typically sold by chemical suppliers. The absence of denaturants means this type of alcohol is significantly more expensive and heavily regulated.
Regulatory Restrictions on Purchasing High-Proof Alcohol
The difficulty in purchasing pure, undenatured ethanol is rooted entirely in federal and state tax law concerning beverage alcohol. In the United States, the Alcohol and Tobacco Tax and Trade Bureau (TTB) imposes a substantial Federal Excise Tax (FET) on all distilled spirits.
This tax is applied per proof gallon. For example, a gallon of 200-proof (100% alcohol) undenatured ethanol represents two proof gallons, and thus incurs a significant tax liability. This FET is the reason that undenatured ethanol, even when sold for non-beverage purposes, is dramatically more expensive than its denatured counterpart.
Purchasing untaxed ethanol for industrial, scientific, or pharmaceutical use requires the buyer to possess specific TTB permits, which are generally inaccessible to the average consumer. The typical retail consumer can purchase high-proof, undenatured ethanol in the form of grain alcohol, such as 190-proof spirits, but only after the distiller or retailer has paid the federal and state beverage taxes.
Furthermore, many state laws impose restrictions on the retail sale of high-proof beverage alcohol, with some states prohibiting the sale of anything above 151 proof (75.5% ABV). These state-level proof restrictions limit a consumer’s access to highly concentrated ethanol.
Practical Sources for Different Grades of Ethanol
The practical source for ethanol depends on the required grade and intended application. Denatured ethanol is the easiest to acquire and is readily found at hardware stores, home centers, and online chemical suppliers. It is sold under various names, such as denatured alcohol or methylated spirits, and is used for cleaning, fuel, and as a solvent for paints and varnishes.
For undenatured ethanol, two main avenues exist, each with different purity and cost implications. The average person can buy high-proof grain alcohol, like 190-proof spirits, from a retail liquor store, provided state laws allow it. This ethanol is taxed as a beverage, making it costly, and is limited to the azeotropic concentration of about 95%.
If a consumer requires non-denatured ethanol for non-potable uses like making tinctures or extracts, specialized chemical or food-grade suppliers offer “food grade” or “USP grade” 200-proof ethanol online. While these products are pure and do not require a federal TTB permit for the end-user to purchase, the supplier is still responsible for ensuring the product is taxed appropriately or is compliant with relevant regulations, and the final price reflects this expense. This food-grade ethanol is the closest a casual buyer can get to “pure” alcohol without industrial permits, but it remains a premium product due to the inherent tax structure.