
Apple syrup is a sweet, apple-flavoured pourable syrup, most rigorously documented as cider syrup made by boiling down apple juice to concentrate its natural sugars.
Cooked-apple aroma leads, over a high sweetness with low acidity; the reduced-juice form deepens into caramel and darker fruit, while the flavoured version stays lighter and more simply sweet.
Poured in small measures as a sweetener that also carries apple character, worked in shaken or stirred. Because purchased products range from thin apple-flavoured sugar syrups to dense boiled-down concentrate, sweetness and intensity vary widely and the dose must be adjusted to the product on hand.
The sweetness is easily matched by any simple syrup, and the body approximated with a richer 2:1 sugar syrup or by reduction — but the defining apple aroma must be preserved, so a genuine substitute has to draw on apple juice, cider or apple concentrate. Where a drink leans on the concentrated cooked-apple character of the reduced-juice form, no ordinary sweetener will stand in.
Apple butter / appelstroop (fruit spread)
Apple butter and appelstroop are spreadable cooked-fruit pastes, whereas apple or cider syrup is a pourable liquid; the same reduced-apple base spans both, depending on how far it is cooked and whether pulp is retained.
The name covers at least two distinct products: a simple sugar syrup flavoured with apple juice or concentrate, and a reduced-juice form made by evaporating water from apple juice or cider to concentrate the fruit's own sugars into a thick syrup without necessarily adding cane sugar. The reduced-juice version carries a caramelised depth from the long boil that the flavoured version lacks.
Once opened, refrigerate and watch for fermentation or mould, as the fruit-juice base is perishable.