Begin by washing the cotton candy grapes thoroughly to remove any dirt or residues. Fresh, clean grapes will ensure that your syrup is free from any impurities.

In a medium saucepan, combine the sugar, water, and grapes over medium heat. Stir occasionally to help the sugar dissolve completely. Bring the mixture to a gentle simmer. As the grapes heat up, stir the syrup frequently, gently crushing the grapes as they cook down. This allows the grape juice to be released into the syrup.

Allow the mixture to simmer for about 15 minutes, stirring frequently. The syrup will gradually thicken as the grapes break down and release their sweetness. Once the syrup has thickened, remove the pan from the heat and set it aside.

Let the syrup cool to room temperature. After it has cooled, strain the mixture using a fine mesh strainer. Squeeze the grapes gently to extract as much liquid as possible. This will ensure that your syrup has all the rich flavors of the cotton candy grapes.

Once strained, transfer the syrup to a clean container and store it in an airtight jar or bottle. The syrup can be stored in the refrigerator for up to three weeks. Be sure to label your container with the date so you can track its freshness.