You can determine how much moisture your hazelnuts have lost by regularly measuring their weight. You need accurate digital scales. This method won’t tell you the absolute moisture level, just whether they are stabilised.
Weigh the sample when nuts are first harvested. Re-weigh regularly until the weight is the same for 3 measurements.
Anyone who has used one of the popular blow/vac machines will appreciate that they blow far better than they suck.
With this in mind perhaps it would be worth trying to blow our nuts onto a tray rather than try to suck them up through a tube.
The Stihl 600 is a backpack blower. It has a four-stroke motor and produces a tremendous controllable blast which is ideal for shifting nuts on rough ground or in long grass, and it has no problem working nuts in damp conditions. This seems the ideal basis for a low-cost harvester.
A year’s worth of effort comes to an exciting but busy end as harvest is upon us. Like most things good, preparation is the key, as you never really know how it’s going to turn out until the very end.
Hazelnuts may start to fall in late February – early March with the majority fallen by the end of March. The colder nights, shorter days and warm midday temperatures in late summer cause the outer husks to swell (hot days) and then contract (cool nights) which eventually cause the nuts to drop. The leaves will also start to turn but should fall after the nuts. A bit of planning is often needed in order to get the nuts up off the ground before the leaves drop. Should the leaves begin dropping during the harvest, a leaf blower is a very useful tool.