Inshell walnuts are considered to be a long-lasting product. However, the shelf life can be significantly reduced if the nut is not prepared for storage and the required temperature and humidity are not maintained.
Preparation for storage is an important process, the nut must be cleaned of the remnants of the pericarp, washed from dirt and juglone and must be dried. The moisture content of freshly picked walnuts reaches 40%, and for storage it should not exceed 10%.
After drying, inshell walnuts are packed in mesh bags or stored in bulk in special places for this. The room must be dry with good air circulation and no sunlight. The optimum storage temperature is from -5 to + 15C (these can be freezers and refrigerators, or a room that meets storage standards). It is believed that the lower the storage temperature, the longer the walnut retains its beneficial qualities. Air humidity during storage should not exceed 55-60%.
The shelf life of walnut kernels is much shorter. A peeled walnut actively separates the oil and becomes bitter over time. To slow down this process, the kernel is stored in an airtight container (glass or vacuum bags) in a dark place. At room temperature, the shelf life of walnut kernels is no more than 1-2 weeks, in a refrigerator – up to six months, with deep freezing – up to a year. The humidity of the environment should be no more than 55-60%.
If the temperature is not observed, the walnut will turn rancid faster, and with high humidity it will become covered with mold or rot. Adhering to the rules of preparation for storage and maintaining the correct temperature and humidity, walnuts will retain their quality and useful properties for as long as possible.