Things You'll Need
If you want to use grapes in homemade preserves or in canning recipes and need to remove their skins, you must blanch them first. Blanching involves dropping fruits or vegetables into boiling hot water briefly and them removing them. The heat from the water causes the skin of the produce to crack and loosen, making it easy to peel away. To successfully blanch grapes, you must drop them into cold water immediately after boiling them. This process prevents the grapes from cooking too much and helps them retain their flavor and nutrients.
Remove any stems from the grapes. Place them in a large strainer bowl or colander and wash them thoroughly.
Fill a large bowl halfway with ice. Fill it up with cold water and set it aside. You will drop your grapes into the ice water immediately after boiling them. If you don't, the internal temperature of the boiled grapes will cause them to continue cooking on the inside. This may ruin their consistency and flavor, as well as prevent them from retaining their nutrients.
Add 2 quarts of water to a 4-quart pot. Heat the water on medium heat until it starts to boil.
Add a handful of grapes slowly to the boiling water. Do not add too many because this may decrease the water's temperature and stop it from boiling, causing the grapes to steep and lose their flavor.
Allow the grapes to boil for about 30 seconds, or until their skins start to crack. Use a slotted spoon to scoop the grapes from the boiling water and drop them directly into the ice cold water you prepared beforehand. Leave the grapes in the water for a few minutes. Remove them with a slotted spoon and place them on a cookie sheet lined with paper towel to drain.