The efficiency of any of the above hullers depends largely upon the speed of the machine and upon the condition of the almonds in the hulls. If the machine runs too fast the almonds will be broken and injured, and if it runs too slowly many of the almonds are not hulled. If the almonds are allowed to hang on the trees too long, or if allowed to lie around too long after being harvested, the hulls become dry and leathery and the difficulty of hulling is greatly increased. Dipping in water in such cases may help to overcome this difficulty to a limited extent.
The papershell varieties, notably the Nonpareil, are much more difficult to hull without breaking the shells than are the harder shelled varieties. The Nonpareil hull has a tendency to close around the nut on drying, making hulling under such circumstances very difficult.
Often when the moisture supply in the soil is exhausted before the nuts are ripe, or where the loss of leaf surface due to mites is serious prior to ripening, the hulls open only slightly or not at all, but dry onto the shell of the nut. Such “sticktights” can only be disposed of profitably by allowing them to thoroughly dry, when they are cracked and sold as kernels.
After the hulling operation all almonds must be gone over by hand to remove pieces of hulls and inferior or gummy nuts. Where canvas drapers are not available for sorting directly from the huller, the nuts are piled in hoppers and sorted on benches beneath them.
Drying.—Immediately following the sorting, the nuts are spread on trays and thoroughly dried in the sun. In the interior valleys during the hot, dry weather the nuts will sometimes dry so quickly that by the time the sorting from hoppers is completed the nuts are sufficiently dry to be bleached. The grower must be certain, however, that such is the case before any bleaching is done, or before the almonds are delivered to the warehouses for bleaching. The nuts are sufficiently dry when the kernels will break without bending. Quick drying is essential to prevent the excessive darkening of the shell.
Bleaching.—When thoroughly dry the nuts are ready for bleaching. The shells are first moistened by spraying with water or subjecting them to low-pressure steam for 10 to 20 minutes. The shells are then subjected to the fumes of burning sulphur for 10 to 30 minutes. The sulphur fumes are absorbed by the moisture on the shells, which are bleached to a bright yellow color. After bleaching the nuts are exposed to the air for a few moments to allow them to dry. The market demands a nut that has been sufficiently bleached to give it a bright, clean, yellow color. An over-bleached almond is equally objectionable because of its pale, sickly, yellow or whitish color. Over-steaming or sulphuring permits excessive penetration of the sulphur fumes, with the resulting danger of absorption by the kernel. While this may not be noticeable in the flavor, it will eventually result in premature deterioration in the form of rancidity. Unbleached almonds remain edible much longer than bleached almonds in nearly every case. Ordinarily one to three pounds of the best flowers of sulphur is required to bleach a ton of almonds. Lump sulphur is not satisfactory.
Sacking.—During the preliminary handling of almonds ordinary grain sacks are commonly used. After bleaching, in which condition they are ready for market, they are put in standard almond bags, measuring 20 × 40 inches and weighing 1¼ pounds. The weight of a bag of almonds will vary, depending not only on the variety but also on the year in which the crop was grown and the locality in which it was produced. For selling purposes the California Almond Growers’ Exchange estimates weights of different varieties to be as follows: Nonpareil about 85 pounds to the bag; I.X.L. about 80 pounds; Ne Plus Ultra, 75 pounds; Drake, 90 to 100 pounds; Languedoc, 100 pounds; and hardshell almonds, 100 to 120 pounds.
Shelling.—Within the past two years the shelling of almonds has taken a prominent place in the consideration of the men charged with the disposal of the almond crop. The increasing popularity of shelled almonds, and the limited market for unshelled almonds, makes the production of more shelled almonds imperative in view of the prospects of greatly increased production in the next few years. A small proportion of the shelled almonds marketed are those accidentally shelled during the hulling process. This probably averages less than 30 pounds per ton of almonds hulled in ordinary years.
The varieties most commonly shelled are the papershells. They are much more easily shelled without breaking the kernels than are the harder shelled varieties and, in addition, are worth more for shelling because of the high percentage of kernel compared to shell.
Grading.—Grading almonds for size is not done at present but probably will be within the next few years. Grading for quality is done regularly by testing an entire lot rather than attempting to separate inferior nuts. The standard grade consists of all lots having the required percentage of good kernels, free from worms or gummy nuts. This requirement varies between 90 and 95 per cent, depending on the condition of the crop as a whole and on the market conditions. The standard grade of a given variety sells on guarantee that it shall be up to advertised standard. All lots which cannot pass this are sold on sample, and therefore, on their own individual merits.