On the United States Department of Agriculture (USDA) side, the classifications of U.S. No.1 grade for the in-shell hazelnut are based on its similar type, dryness, well-formed, clean and bright, blank, split shell, and damage.
- Similar Type
The filberts in each container are of the same general type and appearance. For example, nuts of the round type shall not be mixed with those of the long type in the same container.
- Dryness
The shell is free from surface moisture, and that the shells and kernels combined do not contain more than 10 percent moisture.
- Well-formed
The filbert shell is not materially misshapen.
- Clean and Bright
The individual filbert and the lot as a whole are practically free from adhering dirt and other foreign material, and that the shells have characteristic color.
- Blank
A filbert containing no kernel or a kernel filling less than one-fourth the capacity of the shell.
- Split Shell
A shell having any crack which is open and conspicuous for a distance of more than one-fourth the circumference of the shell, measured in the direction of the crack.
- Damage
Any specific defect described in this section; or an equally objectionable variation of any one of these defects, any other defect, or any combination of defects which materially detracts from the appearance, or the edible or marketing quality of the filberts.
Source:
United States Standards for Grades of Filberts in the Shell