Freeze berries individually or in portions. In either case, first wash them by placing them in a colander and swishing it in a bowl of cold water. Lay out the berries on paper towels and let them dry completely.
To freeze berries individually, spread them on a baking sheet and place them in a freezer until they are solid. After they are frozen, put the berries in a freezer bag or container. This method makes measuring berries easier when you need them. However, you can also freeze berries by simply placing the washed and dried fruit directly into a freezer container. With this method, raspberries tend to freeze together as a mass.