Homemade jams made without pectin will always be looser than store-bought jams or jams made with commercial pectin. If, after sitting in the fridge overnight, the consistency is still too loose for your taste, here are some ideas to thicken it up. 1. Add a tablespoon of chia seeds, and let the jam sit for a few hours more in the fridge. The chia seeds will expand and absorb the extra liquid. 2. Try cooking the jam in the microwave for another five minutes. 3. Mix a teaspoon of cornstarch with a bit of the loose jam until the mixture is smooth, and add it to the jam. Cook in the microwave for a few minutes or until the jam has thickened. This method may make your jam a bit cloudy. 4. Add some Ultra-gel, an instant cornstarch-based thickener that can be stirred into cold jam. Loose jam is not the end of the world, and it still will be delicious. You can always use it as syrup and drizzle it over pancakes, waffles, or ice cream.