Making raspberry syrup is a straightforward process involving fresh, thoroughly rinsed raspberries that are simmered with water and optionally lemon to separate the juice from the solid fruit material. After simmering, the berries are separated with a mesh strainer, sieve or cheesecloth and then tossed. The resulting red liquid is boiled with sugar, increasing the sweetness and reducing the consistency, and then refrigerated.
For the best raspberry syrup, skim away any foam that rises during the simmering stage. Before straining the berry solids in the next step, let the hot berries rest for about 15 minutes to make them easier to handle. Pressing down on the material as it strains provides more liquid but may make the syrup cloudy instead of clear. After adding the sugar and dissolving it by bringing the liquid back to a boil, it may be necessary to continue skimming off foam. The thickness of the syrup increases if the berry liquid is boiled longer. Raspberry syrup is a useful addition in many mixed beverages as well as being a fruity accent for desserts. When reduced to a thicker consistency, it is suitable for pancakes. Raspberry syrup remains good for some weeks when kept in a sealed glass container.