Place the blackberries, blueberries, raspberrries, 3 cups of water and sugar in a medium pot over high heat. Bring to a boil and reduce heat to medium-high and simmer for approx 5 minutes.

Add the strawberries and bananas and for approx 3 minutes. The bananas and strawberries keep their shape when cooked quickly. This will give your kissel texture.

Taste kissel and add more sugar if necessary. This will depend on the natural sugars in your fruit.

Add the potato starch to water in a small jug, and slowly pour into kissel. Stir constantly while kissel thickens (do not stop stirring!). If you want a thicker consistency, add 1 more tablespoon of starch to ¼ cup of water and repeat process.

Remove from heat. Can be served hot or cold in glasses or bowls.