apple juice
Juice pressed from apples, typically filtered and pasteurized. Used in cooking mainly for its sweetness, acidity, and apple flavor rather than as a beverage -- reducing it by simmering concentrates all three at once, so a sauce built on reduced apple juice gets sweeter and more tart together, not just thicker.
Buying guidance
Choose 100% juice rather than a sweetened juice drink unless you specifically want the extra sugar -- "juice cocktail" or "juice drink" on the label means diluted, sweetened product, not the same ingredient. Taste it before cooking with it; sweetness varies noticeably between brands and fruit lots.
Substitutions
- Apple cider -- the closest swap; slightly less filtered and sometimes a bit more tart, but works interchangeably in most cooking.
- White grape juice or pear juice -- similar sweetness and body, but a different fruit flavor; fine when you mainly want liquid and sweetness rather than apple flavor specifically.
- Light stock plus a spoonful of sugar -- works when you need the liquid volume more than the fruit character.
Tips & common mistakes
Because reduced apple juice is mostly sugar and water, it goes from syrupy to scorched in the final minute of reduction -- watch it closely near the end and pull it off the heat as soon as it coats a spoon, since carryover heat keeps thickening it further.
Storage
Once opened, apple juice can ferment slightly if it sits too long even under refrigeration, developing a faint fizzy or boozy edge that signals it's past its best. It freezes well in small portions, like ice cube trays, for a splash of flavor without opening a full container each time.