Onion Cold Storage

The process of storing onions.

A well dried and stored onion has a dry and crispy skin, but is juicy at the inside!
To be able to successfully store onions the following criteria must be met:
The onion must be of a variety that is fit to store.
Should have been harvested when physiologically, completely mature.
The bulb must be firm and compact.

Onions can be stored at two temperatures (ranges):
Around 2°Celsius. This is the optimal storage temperature, under which good storable onions can be stored up till 12 months. The major disadvantage of this temperature is the long period necessary to raise the temperature above the Local Dew Point.

A good alternative temperature range, especially when storage time does not exceed 3 to 4 months, is from 25 °Celsius to 32 ° Celsius. In this temperature range the bulb, which is still a living organism, hardly has any respiration and will, therefore, hardly lose any weight.

In both cases cole room relative Humidity has to be maintained between 75% and 80%.

Note: The onion bulb will lose serious amount of weight while stored at temperatures between 5 to 25°Celsius, through respiration and the temperature range between 20 to 25°Celsius is especially dangerous because of the activity of certain bacteria and fungi.

During the storage process the ventilation will be minimal. Because DRY is DRY and we don't want to lose unnecessary weight through respiration, (despite the fact that at the storage temperature levels the expiration is close to zero). The only reason for the ventilation is to avoid the build-up of the CO2 in between the onions.