 They should be kept cool at all times, including in shops when on display for sale.To preserve their freshness for a few months with no artificial refrigeration, the chestnuts can be soaked in cold water for about 20 hours immediately after harvest, after which they are dried in the shade, then layered in dry sand.Chestnuts behave similarly to seeds in that they produce very little ethylene, and their respiration rate is low, varying between 5 and 20 mg/(kg·h) depending on the temperature.