Isobutane
A safe and effective aerosol propellant.
- Category
- Propellants
- Vegan
- Yes
- Vegetarian
- Yes
What it is
An isomer of butane, used as a propellant for food sprays.
How it is used in food
Isobutane liquefies under modest pressure, so a small volume of liquid propellant can empty a whole can at a steady, controllable spray rate. Because it is chemically inert and displaces air inside the container, it also protects fats in products such as cooking-oil sprays and dairy toppings from oxygen and premature rancidity, and it flashes off completely at room temperature so it contributes no taste, odour or calories.
Commonly found in- Aerosol cooking sprays
- Baking release sprays
Health and safety
Evaporates immediately; not consumed as part of the food.
JECFA and EFSA have both evaluated propane, butane and isobutane as propellants and concluded no numerical ADI is needed, since exposure from food is negligible: the gas evaporates on discharge and any dissolved trace is exhaled unchanged rather than metabolised. In the EU their use is deliberately narrow — vegetable-oil pan sprays for professional use and water-based emulsion sprays — so the safety judgement rests on very limited, well-characterised exposure rather than on broad permission.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| Australia & New Zealand FSANZ |
Permitted | Permitted under the FSANZ Food Standards Code. |
| European Union EFSA / European Commission |
Permitted | Authorised for food use under EU regulations (Annex II). |
| United States FDA (Food and Drug Administration) |
Permitted | Authorised for food use by the FDA (often GRAS for standard additives). |
Identification on labels
- E-number
- E943b
Worth knowing
Isobutane is the branched isomer of butane — the same molecule sold as refrigerant R-600a in modern fridges and burned in pocket lighters. It became a food-industry staple after the Montreal Protocol phased out chlorofluorocarbon propellants, which had been ozone-depleting; hydrocarbons were the drop-in replacement that worked at similar pressures.
Conclusion
A safe and effective aerosol propellant.
References
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Open the appEntry last reviewed 2026-07-28.
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