Room temp booze can be lit on fire at at least 50 proof. 101 proof liquor is commonly used for this. Heated up it doesn’t need to be that high, even some wines can be lit heated in a pan. Almost all liquor can be.
For both it’s the volatile alcohol fumes coming off the liquor that burn, so you just need enough fuming off to hit the right air fuel mixture. A lot like gasoline.
