Recipe(tried): Frosted Grapes

I've never heard that syrup can be used for this purpose. I think syrup would not dry and would remain sticky. Beaten egg whites are usually used for this purpose. Pasteurized eggs or egg whites are readily available and will prevent any risk of salmonella.

This is the method I have used:

You'll need about 1 pound of room temperature grapes (seedless if for eating), still on their stems. Make sure the stems are fresh and green, and the grapes firmly attached for the best result.

3 large egg whites (or 1/3 cup pasteurized liquid egg whites)

About 1 cup superfine sugar

With scissors, carefully cut the bunch of grapes into 2, 3 and 4 inch clusters. A variety of sizes will create a more interesting display.

Line a rimmed baking sheet with parchment or wax paper. Set a wire rack over the pan. Place the egg whites and 2 teaspoons of water in a small tea cup and stir with a fork to blend. Holding a cluster by the stem, dip the grapes into the egg whites. Use a small brush to carefully paint any part of the grapes that did not get dipped into the whites. Place the grape cluster on the wire rack and immediately sprinkle with some of the sugar, turning the grapes in order to coat all sides of the fruit. Pick up the cluster and gently shake off excess sugar. Repeat with remaining grapes. Tip: vary the amount of sugar on some of the grapes to create a natural effect, rather than have all the grapes look the same.

Allow the grapes to dry completely at room temperature, about 2 hours. The sugared grapes will keep at room temperature for up to 2 days. Do not cover or refrigerate or the coating will be ruined.