
Raspberry vodka is a flavored vodka — a neutral base with a predominant raspberry flavor.
Vodka brings the strength and the berry is aroma without acidity or color worth the name. Muddled fresh raspberry with plain vodka gives all three and needs straining.
The liqueur is weaker — usually under 25% against 37.5% — and distinctly sweeter. At the same measure it both dilutes and sugars the drink: pour about half as much and drop the syrup.
The raspberry note is built on esters, and esters fade. An opened bottle loses definition over months rather than years — still recognizably fruity, less recognizably raspberry. Keep it closed and out of the light, and buy for the turnover the bar has.