Put the berries and the Xylitol in a pan and bring slowly to a boil.
Let simmer on medium heat for about 5 to 10 minutes, until most berries have 'popped'.
Add lemon juice. Taste to see if you need to add more sweetener or extra lemon juice.
Add chia seed and let simmer for an additional 2 to 3 minutes or until the jam has visibly thickened. Don't worry if it seems a little bit runny as the chia seeds will absorb more liquid while the jam is cooling down.
Pour jam in a glass jar, put the lid on and let cool on the counter. Once cooled, keep it refrigerated.
*Add to taste. Can also be substituted by other sweeteners, sugar, honey, maple syrup.