fresh raspberries
sugar
Certo-gel

Blackberry Acid is a refreshing non-alcoholic drink that has been prepared in parts of the rural south since great grandpa's time. Actually, it is a blackberry juice concentrate that, mixed with ice water and a little sugar, makes a refreshing, invigorating, summertime drink. Here's how it is made:

Take about two gallons of ripe blackberries and add a half gallon of water and five ounces of tartaric acid. Put all this in an old churn, crock or large glass jar, not in metal, and let stand for 24 hours. Then, squeeze and strain the berries, discarding seeds and pulp. For each quart of juice, add a quart of sugar and stir until well dissolved. Let the sugar and juice mixture stand in a nonmetal container for three or four days. Then, transfer it to a nonaluminum vessel and bring it to a quick boil. After that, transfer to bottles or jars and seal quickly. This will keep for months. To use it, simply mix some of the acid with ice water and a little sugar.

If tartaric acid is not available use cream of tartar dissolved in water.