Too much vanilla extract can do more than give your custard an aftertaste. It can also give you a police record.
Alcohol: Forbidden for Drivers, Mandatory for Vanilla
Federal law states that vanilla extract must be at least 35 percent alcohol, and have 100 grams of vanilla beans per litre.
35 percent alcohol is 70 proof – five times an average beer, well over twice what most wines have. You can buy rum or liqueurs with a similar alcohol content, and most people who like to drink do that instead of drink vanilla.
It is unlikely, however, that the vanilla extract in your bread pudding will get you drunk, or even register on a breathalyzer. Most recipes call for a teaspoon or two at most which, when spread out over a whole dessert and baked to boot, will yield no more than a trace amount of alcohol.
North Carolina imposes strict penalties on DWIs, including fines, license suspension, imprisonment, community service, and an ignition interlock requirement (because of the .15 BAC level).
Vanilla extract is great stuff. But it belongs in the kitchen, not on the road.