The Apricot Sour is a simple drink, but surprisingly difficult to balance, given the incredible range of sweetness present in apricot spirits. As written in The Joy of Mixology, the recipe calls for “apricot brandy” – but given that many apricot liqueurs were called brandies at the time (and many still are), we believe the sweeter liqueur is what was intended for this drink.
That said, we’ve had it with lightly-sweet apricot brandy, and it’s very tasty (although a bit unsweet for some). A crystal-clear, bone-dry eau de viex will impart a lovely, sophisticated flavor, but may require a touch more syrup to be balanced.
If you do use a liqueur here, it’s got to be a good one, since it’s the central ingredient. Look for something French like Merlet or Giffard, or try one of the newer bottlings from Bitter Truth or Rothman & Winter.