For export for year-round consumption, filberts must be stored for one year, and to tie-over a short crop it may be desirable to store them two years. It is well to estimate the probable storage period at harvest time, then grade and store the lots under conditions which would assure adequate storage at minimum cost.
After the filberts are dried to an in-shell moisture content of 7 to 8%, or a shelled moisture content of 3 ½ to 4 ½ they should be closely graded, fumigated and sealed in plastic lined boxes, bags or bins. The purpose of the plastic is to stabilize the moisture and prevent the absorption of flavors from other products. They should not be allowed to change weight by substantial gain or loss in moisture. The storage life depends largely upon the temperature.
At 70oF, or lower, filberts will keep in good condition for 14 months. They should be inspected at intervals for insects, mold and other forms of deterioration. Redrying, refumigating or rabagging may be required.
At 32o to 35oF with 60 to 65% relative humidity, filberts will keep for two years without insect or mold growth; also the bags or boxes need not be sealed.
At 25o to 27oF, with 60 to 65% relative humidity, filberts may be stored in bulk for four years. They should be removed to 35o to 40oF for 24 hours before being brought to room temperature, to prevent moisture condensation.