PCC | Choosing the right cooking oilTypes of oils Natural fats contain varying ratios of three types of fats: saturated, monounsaturated and polyunsaturated. Saturated fats are solid at room temperature and very stable. They resist oxidation, so they often can tolerate higher temperatures. Polyunsaturated fats are liquid at room temperature and generally the least stable for cooking. Monounsaturated fats also are liquid at room temperature and generally are more stable than polyunsaturates. Pressed vs. chemically extracted PCC buyers seek out culinary oils that are mechanically pressed from the seed without using chemical solvents. Olive, avocado and walnut oils, for example, are from soft fruit or nuts that need only expeller pressing and centrifuging. Hard oilseeds, such as soy or canola, usually require some pre-treatment such as steam before pressing but the brands at PCC still do not rely on chemical solvents. In contrast, mass-market oils generally are extracted with toxic solvents such as hexane. Unrefined oils No. No.