Dump the sugar into a thick-bottomed pan.
Pour in the liquid.
Boil over high heat, uncovered, until the sugar dissolves.
Add the rest of the ingredients.
Lower the heat to medium and continue boiling, uncovered and without stirring (stirring causes crystallization, for some reason), until the mixture is almost syrupy. Ten to twelve minutes. DO NOT wait for it to turn too thick as the sauce will thicken some more as it cools.
Cool the sweet and sour sauce. Transfer to a jar or a bottle and keep in the fridge. It’ll stay good for weeks.