By Harold McGee
Stick and tub margarines are the two most common kinds. They are formulated to approximate the spreadable consistency of butter at room temperature, and to melt in the mouth. Stick margarine is only slightly softer than butter in the refrigerator, and like butter can be creamed with sugar to make icings. Tub margarine is substantially less saturated and easily spreadable even at 40°F/5°C, but too soft to cream or to use in layered pastries.
Reduced-fat spreads contain less oil and more water than standard margarines, rely on carbohydrate and protein stabilizers, and aren’t suited to cooking. The stabilizers can scorch in the frying pan. If used to replace butter or margarine in baking, high-moisture spreads throw liquid-solid proportions badly out of balance. Very-low-fat and no-fat spreads contain so much starch, gum, and/or protein that there’s nothing there to melt when heated: they dry out and eventually burn.