Nuts can be roasted either with or without oil – producing ‘oil-roasted’ or ‘dry-roasted’ nuts, respectively.

Perhaps surprisingly, the total fat content is relatively similar. This is because nuts are already high in healthy fats, so they absorb very little (only around 2-5%) of the oil they are roasted in.

Oil-roasting nuts

There are two ways to roast nuts with oil.

Batch oil roasting: With this method, nuts go into a stainless-steel basket and are cooked in hot oil in a machine similar to a chip fryer.

Continuous roasting: Nuts travel through roasters continuously via a mesh conveyor system.

The Australian nut industry uses both methods, with nuts usually roasted in the same oil as the nut itself. For example, oil-roasted almonds are typically roasted in almond oil. Sometimes, other unsaturated oils are used such as peanut, sunflower or canola.

The oils are tested for quality before use, and the type of oil is chosen to maximise the freshness and shelf life of the nuts.

Dry-roasting (or oven-roasting) nuts

With this method, nuts are tumbled around in a machine (which is similar to a miniature cement mixer), or in a round cylinder, which passes over gas fired burners. The nuts are continuously tossed around to give an even distribution of heat, which helps prevent scorching or burning.

Dry-roasting can be also done at home:

• On the stovetop in a frying pan, tossing or stirring the nuts gently over the heat, or
• In a single layer in the oven on a baking tray, stirred from time to time.