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Harvest
Nuts from hybrid and American hazelnut shrubs generally do not fall free from the husk like they do from European hazelnuts. Thus, the clusters need to be picked from the bush. At this stage, most growers in the Upper Midwest have small plantings and do the harvesting by hand. Based on time trials in our Bayfield planting, we estimate hand harvesting can be done at a rate of 13 lbs in-shell nuts per hour. At any commercial scale of production this is too slow, so mechanical harvest is the answer. Straddle-type harvesters are the technology of choice right now for a couple of reasons. First, the shrub-type plants being grown in the Midwest right now are conducive to straddle harvesting. Second, the Midwest gets too much rain during the harvest season to allow for sweeping nuts off the ground. Vacuuming clusters off the ground could also be an option where wildlife pressure is low. |
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Straddle-Type Harvesters
Straddle harvesters are commonly used in bush-fruit crops like blueberries, aronia, currants, and even grapes. Such straddle harvesters come in many different sizes and also use different harvest mechanisms. Pioneering hazelnut growers successfully demonstrated use of slapper-type straddle harvesters which led our research team to investigate other mechanisms and machines. The video to the right shows some of that equipment in action. We have found that straddle harvesters are well-suited to bush-type hazelnuts and can remove clusters with little damage to the plants. |
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De-Husking
Because the nuts do not fall free from the husk from hybrid or American hazelnuts, they must be mechanically removed from the husk. The longer they can hang on the bush to dry the better, but because wildlife love to eat hazelnuts, most growers will pick as soon as the nuts have abscised and are loose in the husk. This means the husks are still green when picked. Although there is equipment to remove the husks when green most growers are drying the in-husk nuts and using beaters of some kind to remove the dried husk from the in-shell nuts. Eventually, the goal is to incorporate removal of green husks into harvesting equipment so de-husking can happen in the field as part of the harvest process. |
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In-Shell Cleaning and Sorting
After de-husking, the in-shell nuts may require additional drying and sanitizing to ensure viable storage. Nuts with husk still attached (stick-ons) must also be removed. Once cleaned, the nuts are then separated into size classes using a roller-sizer or drum-sizer. De-husking, cleaning, and size-sorting in-shell hazelnuts is considered part of the harvest process and no food processing license or inspected facility is necessary. The in-shell nuts may be sold directly to consumers or wholesale to retailers. |
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Cracking
In-shell nuts can be stored for more than a year and cracked as needed. Cracking is done in two ways: compression cracking with the nut squeezed until the shell cracks or impact cracking with the nut thrown against a hard surface to crack the shell. The cracking process produces a mix of whole kernels, split kernels, half-cracked nuts, and shell fragments. The goal is to maximize whole kernel crack-out as separation of split kernels from shell fragments is challenging. |
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Post-Crack Cleaning/Separation
The goal of post-crack cleaning is to separate the whole and split kernels from the shell fragments, uncracked, and half-cracked hazelnuts with as little labor as possible. There are many different ways to accomplish this, but the process typically includes mechanical sorting and aspiration. The video at right shows a vibratory feeder dropping in-shell nuts into a compression cracker and the post-crack mix being passed under vacuum aspiration to remove the shell fragments. |
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Food Safety
Because of low water activity levels, nuts are not considered a "potentially hazardous food" by regulators, however, with poor handling, nuts can become contaminated and make people sick. Thus, anyone involved in the cracking and sale of hazelnuts MUST be cognizant of food safety. This means food safety protocols on the farm, at the processing facility, and at every point in between. Commercial hazelnut processing generally includes steps to sanitize the surface of the in-shell nut before cracking and then a log-5 kill step of the kernels prior to packaging, such as roasting or steam pasteurization. Currently, most processors in the Upper Midwest are using water-based disinfectants to sanitize the in-shell nuts and then roasting the kernels.
Because of low water activity levels, nuts are not considered a "potentially hazardous food" by regulators, however, with poor handling, nuts can become contaminated and make people sick. Thus, anyone involved in the cracking and sale of hazelnuts MUST be cognizant of food safety. This means food safety protocols on the farm, at the processing facility, and at every point in between. Commercial hazelnut processing generally includes steps to sanitize the surface of the in-shell nut before cracking and then a log-5 kill step of the kernels prior to packaging, such as roasting or steam pasteurization. Currently, most processors in the Upper Midwest are using water-based disinfectants to sanitize the in-shell nuts and then roasting the kernels.
Hazelnut Processing Licenses/Permits
Hazelnut processing regulations vary by state. Before selling hazelnut kernels or food products made with hazelnuts always contact your state's Department of Agriculture to determine exactly what licenses or permits may be necessary. Regardless of required licenses, food safety should always be a priority. There are examples in all nut industries of consumers getting sick from eating nuts contaminated with food borne pathogens. A HACCP plan (Hazard and Critical Control Point) for your nut processing is always a good idea. In Wisconsin, in-shell nuts can be cleaned, sorted, and sold direct or wholesale without a license. Cracking and cleaning are considered food processing and selling any volume of kernels therefore requires a food processing plant license. Obtaining that license requires conducting the cracking in a facility and with equipment that meets WI food code. In Minnesota, a food processing plant license is also required, however the MN Cottage Food Law provides exemptions to the requirement for small producers selling direct to the end consumer.
Hazelnut processing regulations vary by state. Before selling hazelnut kernels or food products made with hazelnuts always contact your state's Department of Agriculture to determine exactly what licenses or permits may be necessary. Regardless of required licenses, food safety should always be a priority. There are examples in all nut industries of consumers getting sick from eating nuts contaminated with food borne pathogens. A HACCP plan (Hazard and Critical Control Point) for your nut processing is always a good idea. In Wisconsin, in-shell nuts can be cleaned, sorted, and sold direct or wholesale without a license. Cracking and cleaning are considered food processing and selling any volume of kernels therefore requires a food processing plant license. Obtaining that license requires conducting the cracking in a facility and with equipment that meets WI food code. In Minnesota, a food processing plant license is also required, however the MN Cottage Food Law provides exemptions to the requirement for small producers selling direct to the end consumer.