Description
Finnish berry soup, or kiisseli, sits somewhere between a fruit soup and a loose pudding. It is made by heating berries with water and sugar, then thickening the liquid with potato starch. In Finland, it is often eaten cold or warm with porridge, rice pudding, yogurt, or on its own after dinner. The texture should be pourable, not set like jelly, and the berries should still taste like berries rather than jam.
Ingredients
- 2 1/2 cups mixed frozen berries (400 g)
- 2 cups water (500 ml)
- 1/4 cup granulated sugar (50 g)
- 3 tablespoons potato starch or cornstarch
- 2-3 tablespoons cold water
Instructions
The frozen berries, water, and sugar go into a medium saucepan. The pan should be set over medium-high heat until the liquid reaches a boil. Try not to stir too much at this stage, especially with softer berries such as raspberries or strawberries, since they can break down and turn the soup cloudy.
In a small bowl, the potato starch or cornstarch is stirred with 2 tablespoons cold water until no dry starch remains. The mixture should look like thin paste. If it feels stiff or clumpy, the extra tablespoon of cold water can be added.
Once the berry mixture has reached a boil, the heat should be lowered. The starch slurry is poured into the saucepan in a thin stream while the soup is stirred at the same time. This helps prevent small starch lumps from forming.
The soup needs to return to a brief bubble after the starch goes in. As soon as it thickens and a few bubbles appear, the pan comes off the heat. Long boiling after adding potato starch can make the texture stringy or dull.
The soup can be ladled into bowls while warm, or cooled to room temperature and then chilled. It is often eaten with porridge, rice pudding, yogurt, or a splash of milk. On its own, it works as a modest fruit dessert.
Notes
Potato starch gives the most Finnish-style texture. It thickens with a clear, glossy finish and keeps the soup closer to the traditional version. Cornstarch works, but the result may look a bit cloudier.
Frozen mixed berries are fine here. Bilberries, blueberries, raspberries, red currants, black currants, strawberries, and lingonberries all work. A mix with tart berries usually gives better balance than only sweet berries.
Do not add starch directly to the hot soup. It needs to be mixed with cold water first, or it will clump on contact.
The soup thickens more as it cools. For a thinner version, reduce the starch to 2 tablespoons. For a spoonable dessert, use the full 3 tablespoons.
The sugar amount can be adjusted depending on the berries. Currants and lingonberries may need a little more. Strawberries and blueberries may need less.
For a smoother soup, the berries can be strained before thickening. For a more rustic version, they stay in the pan.
- Prep Time: 5 min
- Cook Time: 8 min
- Category: Dessert
- Method: Simmering
- Cuisine: Finnish
Nutrition
- Serving Size: 1 cup
- Calories: 120
- Sugar: 18g
- Sodium: 3g
- Fat: 0.4g
- Carbohydrates: 30g
- Fiber: 4g
- Protein: 1g