To store: Keep the homemade Nutella in a sealed jar at room temperature for up to 2 weeks. You can also keep it in the fridge, but it will begin to harden and lose its creaminess. How to store raw hazelnuts: Prolong the life of your hazelnuts by storing them in an airtight container in the freezer for about 1 year. Make sure to place them in the freezer right after purchasing!