Slip the grapes out of their skins and separate the flesh from the skins. Puree the grape skins in a food processor for 2-3 minutes. Strain through a fine mesh sieve to remove any leftover grape skin.

In a large saucepan over medium heat, cook the grape flesh until it releases some juice and starts to break down, about 5-7 minutes. Strain the flesh through a fine mesh sieve using a wooden spoon to push it through while removing the seeds.

Return the strained grape skins and flesh to the large saucepan over medium heat for 5 minutes. Remove from the heat and stir in the lemon juice, agave and chia seeds. Cool to room temperature before transferring to a jar or other airtight storage container. The jam will be thicken more once it is fully chilled.

Store in the refrigerator for 2 weeks or freeze up to 3 months. Thaw in the refrigerator.