The potential for infield hulling of early harvest almonds

J.M. Fielke, M.C. Coates
Dried almonds are currently harvested and transported to hullers and shellers for processing with their hulls attached. The hull accounts for approximately 45% of the mass of a dried almond and if they could be removed, the volume for storage and transport would be approximately halved. Prototype equipment is being developed at the University of South Australia that used multiple impacts of the fruit against a steel surface with the aim of detaching the hulls with minimal creation of loose kernel. To evaluate the prototype's ability to hull almonds at various stages of hull split and drying, 'Nonpareil' almonds were hand harvested weekly at Walker Flat over 7 weeks and a whole of tree “shake and catch” test was undertaken at Murtho. The samples were brought back to the laboratory for hulling evaluation. If earlier harvesting and mechanical dehydration is feasible, then growers can take the fruit out of the orchard earlier and avoid late season damage to the kernels from insects and extremes in weather. The testing showed that the hulls were most easily detached from the fruit when they had a hull split with an opening of approximately 10-15 mm. For this stage of hull split, over 90% of hulls were able to be detached without producing any loose kernel. Dried almonds were harder to hull than early harvested almonds with only 45% of dried almonds having their hulls detached using the same impact settings. Combined with appropriate dehydration equipment, this development has the potential to offer new ways that almonds can be harvested.
Fielke, J.M. and Coates, M.C. (2018). The potential for infield hulling of early harvest almonds. Acta Hortic. 1219, 235-242
DOI: 10.17660/ActaHortic.2018.1219.37
cavities, concealed damage, hull split, shake and catch, weather damage

Acta Horticulturae