Dark-colored berries -- including raspberries and blueberries -- are among the best dietary sources of disease-fighting antioxidants. You can incorporate berries into your diet in any number of ways. Mix them into yogurt or cereal or add them to pancakes or waffles. Berries are delicate and have a short shelf life, though. If you have more berries than you can use before they go bad, try freezing them to extend their life.
Place the raspberries or blackberries in a colander or another drainer set in the kitchen sink.
Rinse the berries with cold water in the colander, and let it sit in the sink for a few minutes to allow excess water to drain.
Spread the berries in a single layer on a cookie sheet or baking sheet and set it on a countertop for a few hours.
Check the berries periodically. Wait until they have dried completely before moving them to the freezer.
Place the cookie sheet with the berries on it in the freezer. Rest it gently on a flat surface so the berries do not all collect in one area or fall off the sheet. Let them sit in the freezer overnight to make sure they freeze all the way through.
Remove the cookie sheet from the freezer and transfer the frozen berries to freezer-safe bags or containers.
Seal the bags or containers so they are air-tight and place them back in the freezer for storage.
Washing the berries is not essential before freezing them, but be sure to do so after thawing if you did not do it earlier.
When filling bags or containers with frozen berries, leave 1 inch of space at the top for a rigid container and 2 inches to 4 inches of space for freezer bags.
Once frozen, berries will keep for between 10 months and 12 months.
To thaw frozen raspberries and blueberries, place the container in the refrigerator. If you need the berries more quickly, place them in water to start thawing them.