Hazelnuts, also known as filberts or cobnuts, are the edible nuts of the Corylus species of trees and shrubs. They have a rich, slightly sweet flavor and a crunchy texture, making them a popular ingredient in baking, confectionery, and as a snack food. The quality and longevity of the harvest depend entirely on correct timing. Picking too early or too late affects both flavor development and the nut’s ability to be stored long-term. Understanding the precise signs of maturity is the first step toward a successful yield.
Visual and Physical Signs of Maturity
The most reliable sign that hazelnuts are ready for harvest is the natural drop of the nuts from the tree. This process typically begins in late August and continues through October in the Northern Hemisphere, depending on the specific cultivar and local climate. The nut gains half of its final weight in the final two weeks before it falls, emphasizing the need for patience before harvesting.
A visible indicator of approaching ripeness is the change in the color of the leafy husk, which transitions from bright green to yellow-brown or fully brown. Simultaneously, the nut begins to loosen and separate from the involucre, or husk, surrounding it. For many varieties, the nut falls completely free of the husk when ripe, while others may remain loosely enclosed.
The internal development of the kernel provides the ultimate confirmation of maturity. If a nut is cracked open, the kernel should have expanded to completely fill the shell cavity. A firm, creamy-colored kernel indicates readiness, while a spongy texture suggests it still requires more time to mature. Consistent dropping signals that the bulk of the crop is ready for collection.
The Mechanics of Gathering Hazelnuts
The physical process of gathering hazelnuts begins with preparing the ground beneath the trees before the nuts start to drop. The area should be mowed or cleared of debris, weeds, and long grass to make the nuts easier to spot and collect. Laying down tarps or specialized netting beneath the canopy is a practical method for smaller-scale operations, as it keeps the fallen nuts clean and simplifies collection.
Since the nuts are best harvested after they have fallen, the primary collection method involves gathering them from the ground. For home growers or small orchards, this is often done by hand-picking or using a soft rake to sweep the nuts into manageable piles. If the natural drop is slow, the process can be gently assisted by shaking the tree limbs to dislodge the ripe nuts.
For larger commercial orchards, mechanical harvesting is the standard, utilizing specialized equipment to streamline the operation. Sweeper machines move the fallen nuts into narrow rows between the trees, followed by a harvester that lifts the material from the ground. These harvesters use tines, belts, and air flow to separate the nuts from leaves, twigs, and other debris before depositing the clean harvest into a storage container. Specialized vacuum devices are also used to suction the nuts directly from the orchard floor.
Essential Post-Harvest Preparation
Once the hazelnuts are collected, immediate cleaning is necessary to remove foreign materials and any nuts that may be moldy or damaged. This initial sorting step is important for preserving the quality of the good nuts and preventing the spread of mold or decay during storage. Nuts still enclosed in their husks should be separated and allowed to dry; removing the husks entirely aids in accelerating the drying process.
The most important step after harvest is drying the nuts to reduce their moisture content. Freshly harvested nuts contain too much moisture for long-term storage and will quickly become susceptible to mold if not properly dried. The target moisture level for in-shell hazelnuts should not exceed 12%, while the kernels should be dried down to about 6% moisture.
To dry the nuts, they should be spread in a single layer on a screen-bottomed tray or a mesh drying rack to ensure maximum air circulation. They should be placed in a warm, dry area, ideally with temperatures ranging from 90 to 105 degrees Fahrenheit. To facilitate even drying, the nuts must be stirred or turned daily, a process that typically takes two to four weeks when air-drying naturally. Once fully dried, the unshelled nuts can be stored in a cool, dark, and dry place for several months.