does unleaded 91 contain ethanol

Short answer: standard Unleaded 91 in Australia generally contains no ethanol.

If ethanol is blended in, the pump will be marked E10 (up to 10% ethanol) and is usually sold as about 94 RON, not 91.

Plenty of servos offer both ULP 91 (no ethanol) and E10; labelling is mandatory, so your eyeballs are the best test kit.

Most modern cars are fine on E10, but some older vehicles, small engines, and boats prefer straight 91—check your owner’s manual.

If you want zero ethanol, choose the bowser explicitly labelled Unleaded 91, not E10, and you’re golden.