Preserving summer produce through techniques like freezing, making jam, and roasting in olive oil extends the availability of nutritionally dense peak-season ingredients well beyond their natural season — allowing the cook to access the higher vitamin and antioxidant content of in-season produce throughout the year. Berries frozen at peak ripeness retain most of their antioxidant content for up to a year, research shows, making the simple act of spreading fresh berries on a sheet pan and freezing them one of the most nutritionally efficient food preservation techniques available to any home cook.