Published January 15, 2005. From Cook's Illustrated.
How do these bottled oils taste compared to using fresh citrus?
Pure citrus oils are not extracts or flavorings—citrus fruit rinds are squeezed to remove the oil, which is then bottled. The question is, how do these oils taste when used as substitutes for fresh zest and juice?
To find out, we bought lemon, lime, and orange oils and tested them in our recipes for pound cake, sugar cookies, and biscotti. While some tasters enjoyed the oils' strong flavor punch, most consistently found the citrus flavor distasteful, describing it as "artificial," "assertively floral," and "bitter." Several tasters independently compared them to Fruit Loops! A second negative was the lack of a standard conversion formula—the oils tasted differently depending on cooking time as well as the presence of other strong flavors, such as almond extract. The oils also need to be stored in the refrigerator to prevent rancidity. In the end, we preferred the real thing.