The traditional method to preserve the onion is the method of drying the onions extracted from the soil with their stems, and then keeping them in a cool cellar, cave or dark warehouse until they are consumed. Unfortunately, this type of primitive storing causes between 40% and 80% loss. Yet, neither economics nor our old world allow such wastes anymore.
After the onion is harvested, it cannot be put into cold storage immediately. First onion needs to be dried. After a few days of this process, the ripening phase comes. After the ripening process, which is created in order to improve the formation of the onion skin and get the specific color of the skin, The temperature of the onions is lowered by a maximum of 0.5 degrees every day and gradually brought to the storage temperature in the warehouse.
Onions are stored in cold storages between 0 degrees and 2 degrees, depending on the type. Onions can be stored in contemporary cold stores for up to 10 months without wastage. Ventilation has vital importance in onion warehouses. Onions that will be distributed to the market after storage are not shipped immediately from the warehouse, they are heated to the regional temperature for a week, and condensation is prevented.
However, while only 20 million tons of 100 million tons of onions produced in the world are stored with these modern methods, unfortunately, the habit of wasting onions continues.