
Maraschino cherries syrup is the sweet, red, cherry-and-almond sugar syrup that cocktail cherries are packed in — the liquid drained from the jar.
Cherry and bitter almond together is the profile, and the almond is what a plain fruit syrup lacks. A drop of almond extract closes most of the gap; the bigger question is whether the jar it came from held real fruit at all.
Maraschino liqueur
A dry, clear distillate from marasca cherries, alcoholic and not sweet in the same way at all; the shared name has ruined more drinks than any other in the cabinet.
Grenadine
Pomegranate, red and sweet, with no almond note. It is a swap of convenience, not of flavor — the drink keeps its color and loses the cherry-almond middle.
The brine-bleach-then-dye method was worked out by Ernest Wiegand at Oregon State — which is how the cherry stopped being alcoholic.
Sealed it keeps for months on sugar alone, and refrigerated once open. It thickens as it loses water, so an old jar pours heavier and sweeter by the same measure.