The almond fruit measures 3.5–6 cm (1–2 in) long. In botanical terms it is not a nut, but a drupe. The outer covering or exocarp, fleshy in other members of Prunus such as the plum and cherry, is instead a thick leathery grey-green coat (with a downy exterior), called the hull. Inside the hull is a reticulated hard woody shell (like the outside of a peach pit) called the endocarp. Inside the shell is the edible seed, commonly called a nut. Generally, one seed is present, but occasionally there are two.
The almond that we think of as a nut is technically the seed of the fruit of the almond tree, a glorious medium-size tree that bears fragrant pink and white flowers. Like its cousins, the peach, cherry and apricot trees, the almond tree bears fruits with stone-like seeds (or pits) within. The seed of the almond fruit is what we refer to as the almond nut.
Almonds are off-white in colour, covered by a thin brownish skin, and encased in a hard shell. Almonds are classified into two categories: sweet and bitter.
Sweet almonds are the type that is eaten. They are oval in shape, usually malleable in texture and wonderfully buttery in taste. They are available in the market either still in their shell or with their shell removed. Shelled almonds are available whole, sliced or slivered in either their natural form, with their skin, or blanched, with their skin removed.
Bitter almonds are used to make Almond Oil that is used as a flavouring agent for foods and liqueurs such as Amaretto. They are otherwise inedible as they naturally contain toxic substances such as hydrocyanic acid. These compounds are removed in the manufacturing of almond oil.
Almonds are commonly sold shelled (i.e., after the shells are removed), or unshelled (i.e., with the shells still attached). Blanched almonds are shelled almonds that have been treated with hot water to soften the seedcoat, which is then removed to reveal the white embryo.
All commercially grown almonds are of the “sweet” variety.
While the almond is often eaten on its own, raw or toasted, it is also a component of various dishes. Almonds are available in many forms, such as whole, sliced (flaked, slivered), and as almond butter, almond milk and almond oil. These variations can be used in both sweet and savoury dishes.
Almonds that are still in their shells have the longest shelf life. If purchasing these, look for shells that are not split, mouldy or stained. Shelled almonds that are stored in an hermetically sealed container will last longer than those that are sold in bulk bins since they are less exposed to heat, air and humidity. If purchasing almonds in bulk bins, make sure that the store has a quick turnover of inventory and that the bulk containers are sealed well in order to ensure maximum freshness. Look for almonds that are uniform in colour and not limp or shrivelled. In addition, smell the almonds. They should smell sweet and nutty; if their odour is sharp or bitter, they are rancid.
For a roasted flavour and texture, choose those that have been “dry roasted” as they are not cooked in oil like their regular roasted counterparts. Yet, even when purchasing “dry roasted” almonds, it is important to read the label to be sure that no additional ingredients such as sugar, corn syrup or preservatives have been added.
Sweet almonds are mainly eaten raw and are also used in bakery products. Bitter almonds are mainly used to produce almond oil.
Since almonds have a high fat content, it is important to store them properly in order to protect them from becoming rancid. Store shelled almonds in a tightly sealed container, in a cool dry place away from exposure to sunlight. Keeping them cold will further protect them from rancidity and prolong their freshness. Refrigerated almonds will keep for several months, while if stored in the freezer, almonds can be kept for up to a year. Shelled almond pieces will become rancid more quickly than whole shelled almonds. Almonds still in the shell have the longest shelf life.
Almonds are usually shipped in cartons or bags. It is a delicate commodity which is easily damaged by moisture, heat, odours or contact with unclean goods, especially when shelled. Moisture damage in shelled almonds occurs when humidity is high. Minor damage may be cleared by ventilation, while heavier damage, seen as mould, can often be rectified by drying and brushing. Heat will cause kernels to become rancid. If not fumigated before shipment, almonds may suffer from infestation. Any such infestation is usually by attack in the country of origin. When water-damaged, almonds can attract flies and subsequent maggot growth which gives off cadaver-type odor. The development stage of beetles, maggots, etc., will provide indication of time of infestation.
At a relative humidity of 65%-70% and -3° / 0°C temperature, almonds have a storage potential of approx. one year. Travel temperatures of approx. 5°C/25°C are feasible, but >30°C should be avoided for longer periods, as self-heating may be promoted. Overseas shipment preferably in ventilated containers.
– Self heating/spontaneous combustion
– Mechanical influences
– Insect infestation