Many people are used to the fact that the walnut is not a demanding tree, it sprouts from walnuts lost by a crow, and the harvest it gives is itself cleaned from the green skin. But based on the experience of the world's walnut growers and processors, recommendations and rules were formed that help to get a harvest of much better quality and earn more from it.
It is desirable to follow all the rules at home as well, and it is especially important - in industrial ones. For small volumes, you can do it manually, and for large volumes, you need automation.
First of all, walnuts must be collected in time. Walnut is considered ripe when cracks appear on the green skin. After that, oxidation processes begin in the peel - tannins, iodine, and juglone begin to darken under the influence of the sun and air and color everything they touch. The longer the walnut is in this shell, the more the shell is dyed and the more dyes seep into the walnut. A late-harvested walnut will almost always end up with a dark kernel.
In some cases, after darkening, the pericarp dries up and the walnut falls out of it. Unfortunately, this does not always happen and quite often the darkened skin dries right on the walnut. It is much more difficult to clean the dried skin and it interferes with the processing of the walnut.
When should the walnut be harvested?
Collection dates will vary in different regions and each year. The timing of the collection is greatly influenced by weather conditions - in warm weather in spring, flowering occurs earlier, which means that the walnut ripens earlier. Therefore, the only indicator worth focusing on is the integrity of the green pericarp. If it starts to crack, nature tells us that the walnut is completely ready for harvesting.
First of all, a walnut that has fallen to the ground is collected, because on the ground, the processes of oxidation of the green skin occur much faster. You can pick a walnut from a small tree, and shake it on the ground from a large one. Industrial walnut orchards use tree shakers for this process.
The harvested walnut is cleaned of the green skin in the shortest possible time and sent to dry.
Timely harvesting is the key to obtaining a walnut with a light, clean shell and a light kernel inside. Such a walnut has the highest value and the highest price when sold. That is, by picking a walnut in time, you can earn more on the same volume of walnuts.