Oil lingo

• Cold-pressed: The oil is extracted from the seed, fruit or nut by mechanical pressing only. There’s little or no heat to extract more oil. After it’s pressed the oil just needs to be filtered and so it tends to keep its natural flavour. You can usually tell a cold-pressed oil by its deep colour, stronger flavour and higher price.
• Expeller-expressed: These oils are obtained by squeezing the seed, fruit or nut at high pressure. Most oils are extracted by this method but don’t qualify as cold-pressed because the high-pressure squeezing generates heat. Expeller-pressed oils still retain most of their flavour, aroma, and colour.
• Refined: Most oils produced on a large scale, such as canola and sunflower, are refined. Refining involves a number of processes that include using heat and chemicals. Bleaching gives the oils a light colour, deodorising removes any aromatic oils or free fatty acids that might be left in the oil to affect flavour, and distilling removes any final material that could cause unwanted aromas. As a general rule, more refining means less flavour and colour.
• Light: It’s light – but in colour and taste only. Like every other oil, light oil is 100 percent fat. (If you want to cut kilojoules, use less.)
• “No cholesterol”: Don’t be impressed by no-cholesterol claims on oils. Cholesterol comes from animal products, so vegetable oils will contain virtually none anyway. 
   

Olive oil

Olive oil has a reputation for being a healthy oil. The health benefits are related primarily to the oil's high levels of monounsaturated fatty acids, and to the presence of natural antioxidants. Antioxidants have been shown to protect against heart disease and cancer.

The higher cost of extra-virgin may mean you keep it for dressings or special dishes where flavour is important. In baking and stir-frying, you may prefer to use milder tasting pure or "light" oil.

• Extra-virgin: The highest grade of olive oil: it's usual to pay a premium for it. Extra-virgin's made from the first pressing of olives, and has minimal processing to maintain the flavour and aroma. As a result, it's the olive oil with the highest levels of antioxidants. Extra-virgin can't have more than 0.8% acidity and must be assessed as fault-free by an expert panel.
• Virgin: Olive oil with minor imperfections and a higher acidity level.
• Pure: A mix of refined and virgin oil, resulting in a milder olive taste.
• Light or extra-light: Refined oil with small amounts of virgin oil added. These oils are "light" in colour and taste, but they're not "light" in fat or kilojoules.