Part of Mediterranean cuisine for thousands of years, olive and grapeseed oils are made by pressing oil from the fruit or seed. Crushing olives without using chemicals creates extra virgin olive oil with its light, medium or robust flavor profile. Although grapeseed oil – with its clean flavor profile -- can be processed using chemicals, when the label says "expeller pressed," you know the oil was extracted without chemicals.
It takes ingenuity to extract the small amount of oil that grape seeds contain. The most economical method is a chemical extraction involving hexane, a petroleum product. This process pulls close to 100 percent of the oil from the seeds. Some cooks, however, are concerned with hexane's potential for harming the environment as well as the possibility of chemical residue in the oil. In contrast, when grapeseed oil is processed using an expeller press, the oil is extracted naturally using a hydraulic press that crushes the seeds. Because this is a less efficient method -- it typically yields only 50 to 70 percent of the seed's oil -- expect to pay more for expeller-pressed oil.
Extra virgin olive oil must be made by crushing fresh olives using purely mechanical means; no chemicals are allowed. The highest quality of the olive oils, it cannot be mixed with any other oils nor contain any additives. It must be extracted and filtered under low temperatures to maintain the oil's integrity. To bear the extra virgin label, the finished product must also pass a chemical analysis as well as a smell and taste test. Like various wines, olive oils have distinctive flavor profiles. Look for notes such as bitter, buttery, peppery, floral, pungent and herbaceous.
Grapeseed oil, with its light taste and slightly nutty flavor, can run the gamut of culinary applications. You can use it to sauté, in baking, in stir fries, for creating herbal infusions, and in salad dressings. Olive oil is more appropriate for low-heat or no-heat cooking such as composing salad dressings or drizzling over bread or steamed vegetables. As olive oil heats up, it loses some of its deliciously distinctive flavor. Both grapeseed and olive oil can take fairly high heat before reaching the smoking point where they oxidize. Grapeseed oil's smoke point of 428 degrees Fahrenheit is only slightly higher than olive oil’s 410 degrees.
Grape seeds contain high concentrations of plant pigments known as flavonoids. Along with the vitamin E and the oligomeric proanthocyanidin complexes they contain, consumption of grape seeds provides antiodixdant properties. Olive oil contains heart-protecting oleic acid -- anywhere from 55 to 85 percent depending on the olives -- along with flavonoids and vitamin E. Oil made from the first press of the olive contains the highest levels of antioxidants.