Place the berries in a bowl and stir in all the remaining ingredients, except the Certo.
Let stand 15 minutes. Add the Certo and stir for 3 minutes, until the sugar is completely dissolved and no longer grainy. Pour into well-washed and dried plastic or glass containers with tight-sealing lids, leaving 1/2-inch head space for expansion during freezing. Let jam stand at room temperature for 24 hours. Refrigerate up to 3 weeks, or freeze up to 6 months.