Wonder if more rasberry taste would not be extracted by cooking them with the sugar and water and then strain?
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I actually think the raw freshness of the raspberries pureed is part of the lightness of the cocktail. Instead of a rich, jam-y taste, you get a right-off-the-bush tang that comes from not cooking the life out of the berries, I believe.
Thank you - that may well be it, but there is one way to find out, right? Try both methods!
I agree that the freshness of the un-cooked raspberries is really a highlight of this syrup base! Consider also that you add the fresh raspberries to hot sugar-syrup so while it doesn't actually "cook" I believe the flavour is really brought out by hitting the raspberries with the hot syrup. If you are considering experimenting with cooking them, I would still add the vinegar after you take it off the heat. Hope that helps!