Roasting hazelnuts intensifies their unique flavor and develops their color. Best results can be achieved using a low temperature and longer time. To roast kernels, spread whole kernels in a single layer on a baking sheet and bake at 275 degrees F. for 15-20 minutes. Take care not to over roast as nuts can scorch quickly. To remove skins, wrap warm hazelnuts in a dish towel and let them sit for 5 to 10 minutes. Rub vigorously in towel. Many varieties do not lose their skins entirely, which is a good thing! Hazelnut skins add nutrients and color.
An easy rule of thumb is the more the nuts are processed, the shorter the shelf life they will have. It is best to process (roast, chop, slice, grind) just before use. However, if you’d like to have hazelnuts handy for adding to a variety of dishes, then simply roast the kernels, dice and freeze in an airtight container away from foods with strong odors. They will keep for over a year in the freezer and you can remove the amount you need, bring them to room temperature and use immediately.