A well-made sorbet is almost as creamy and smooth as ice cream. But rather than finishing with mouth-coating richness, it should be delicately icy and dissolve on the tongue, leaving behind an echo of clean, concentrated fruit flavor. In true Cook’s Illustrated fashion, we turned to science to figure out how to get the best end result.
THE SCIENCE OF ICE CRYSTALS
Adding both water and sugar is crucial to achieving the perfect consistency, as the two work in tandem. The problem is that the optimal amount of sugar makes the sorbet require too much water, which compromises its texture. Fortunately, we had an idea about how to minimize the water while minimizing ice crystals: separating out a small amount of the base and freezing it separately, then adding it back into the rest of the sorbet. Because the small portion freezes much more rapidly than if we tried to freeze the whole batch, there isn’t enough time for large crystals to grow, and instead very small ice crystals form. Then, when we add this frozen mix back to the rest of the base, the tiny crystals trigger a chain reaction that very rapidly form equally small crystals in the bigger mix.
As for the flavor, the raspberries’ natural pectin and an additional bit of powdered pectin (bloomed first in water) keeps the sorbet from immediately puddling without overdoing the firmness.
The final step in successful sorbet is perfecting the churning time. We found that 18-20 minutes was the best time range, but even more important was a visual cue that indicated the sorbet was done churning: the color of the mixture began to lighten up considerably soon after it started to thicken. This was a sure sign that it was beginning to take on air and was in need of a transfer to the freezer.
HOW TO MAKE RASPBERRY SORBET
1. Combine 1 cup water, 1 teaspoon pectin, and 1/8 teaspoon salt in medium saucepan.
2. Heat over medium-high heat, stirring occasionally, until pectin is fully dissolved, about 5 minutes.
3. Remove saucepan from heat and allow mixture to cool slightly, about 10 minutes.
4. Process 1 1/4 pounds raspberries, 1/2 cup sugar, 1/4 cup light corn syrup, and pectin mixture in blender until smooth, about 30 seconds.
5. Strain mixture through fine-mesh strainer, pressing on solids to extract as much liquid as possible.
6. Transfer 1 cup mixture to small bowl and place remaining mixture in large bowl. Cover both bowls with plastic wrap.
7. Place large bowl in refrigerator and small bowl in freezer and cool completely, at least 4 hours or up to 24 hours. (Small bowl of base will freeze solid.)
8. Remove mixtures from refrigerator and freezer. Scrape frozen base from small bowl into large bowl of base. Stir occasionally until frozen base has fully dissolved.
9. Transfer mixture to ice cream machine and churn until mixture has consistency of thick milkshake and color lightens, 15 to 25 minutes.
10. Transfer sorbet to airtight container, pressing firmly to remove any air pockets, and freeze until firm, at least 2 hours. Serve.
RECIPE FOR MEMBERS: Raspberry Sorbet
For our cool, creamy raspberry sorbet recipe, we super-chilled the base and used just the right ratio of sugars to water to ensure the finest-textured ice crystals possible. We also bumped up the berries’ natural amount of pectin to give the sorbet stability both in the freezer and out.