Place raspberries or wild strawberries in a jar with an opening below. Wrap paper around the top and set the jar in the oven after baking bread. When the berries rise and give off their juice, let the jar cool, and release the juice [through the bottom opening] into bottles with necks.
Some people set this juice in a window on the sunny side of the house for a full week before straining it into bottles. Stop up the bottles tightly and seal them with tar. In the summer keep the bottles in the cold cellar, and in winter in a dry basement, overturned so their necks are in dry sand. A similar juice may be prepared in winter for kvass, kissel, syrup, etc.