Roasting marshmallows over an open flame is a classic tradition, but the choice of fuel for that flame is crucial for both safety and health. While rubbing alcohol, which is primarily isopropyl alcohol, does burn, it is not an appropriate or safe substitute for cooking fuels.
The Direct Safety Verdict
The immediate and definitive answer is that roasting marshmallows over rubbing alcohol is unequivocally unsafe and poses serious health risks. Rubbing alcohol is formulated as a topical antiseptic and solvent, not as a fuel for food preparation. It is fundamentally different from food-grade alcohols like ethanol, which are sometimes used in specific chafing dish gels. Unlike cooking fuels, rubbing alcohol contains impurities and is not manufactured under food-safe standards. The act of cooking involves the flame coming into direct contact with the food, allowing combustion byproducts to contaminate the marshmallow.
Chemical Composition and Toxic Byproducts
Standard rubbing alcohol is typically a mixture of 70% to 91% isopropyl alcohol and water. When this compound burns, the combustion process is often incomplete, especially in an open, un-engineered setting. Complete combustion of any hydrocarbon yields relatively harmless carbon dioxide and water vapor, but incomplete combustion produces a range of toxic substances.
The incomplete burning of isopropyl alcohol generates harmful volatile organic compounds (VOCs) and particulates. These byproducts can include acetone, the main liquid product of isopropanol oxidation, and carbon monoxide, a highly toxic gas resulting from oxygen-starved flames. These invisible fumes and micro-particles rise with the heat and can settle directly onto the marshmallow.
Inhaling these combustion byproducts, even in small amounts, can irritate the respiratory system and affect the central nervous system. Isopropyl alcohol itself is toxic if ingested, and the contamination of the food by its combustion chemicals bypasses the body’s natural defenses. The acute effects of exposure to these fumes can include headache, dizziness, and nausea.
Fire Hazards Beyond Consumption
The risks associated with using rubbing alcohol extend beyond food contamination to immediate physical fire hazards. Isopropyl alcohol has a very low flash point, which is the minimum temperature at which a liquid gives off enough vapor to form an ignitable mixture with air. For 70% isopropyl alcohol, the flash point is approximately 70°F (21°C), meaning it is highly volatile and easily ignitable at room temperature.
This high volatility creates a significant risk of flash fires, particularly if a container is being refilled near a heat source or a residual flame. Furthermore, the flame produced by burning alcohol can be nearly invisible in bright lighting conditions, making it incredibly difficult to detect. An unseen flame poses a severe burn risk, as people may unknowingly reach over or touch the burning fuel source.
The vapors of isopropyl alcohol are also heavier than air, which means they can travel along surfaces and accumulate in low-lying areas, creating an explosion hazard if they encounter an ignition source. This combination of an invisible flame, high volatility, and heavy, flammable vapor creates an unpredictable fire scenario.
Safe Alternatives for Roasting
For a safe and enjoyable marshmallow roasting experience, it is best to use fuels specifically designed for cooking.
- Traditional hardwood or lump charcoal provides a clean, natural heat source widely accepted for food preparation.
- These materials burn at high temperatures and impart a desirable smoky flavor without producing dangerous chemical contaminants.
- Propane and natural gas fire pits are also safe alternatives because the gas burns cleanly, producing minimal byproducts.
- If an indoor or tabletop option is desired, look for gel fuels explicitly labeled as food-safe or designed for chafing dishes and s’mores kits.
These gels typically contain food-grade ethanol, which burns much cleaner than isopropyl alcohol and is manufactured with consumer safety in mind.