However, a free fatty acid (carboxylic acid and/or carboxylic acid derivative) can advantageously include an acyl moiety containing at least four carbons (preferably at least 6 carbons, for example at least 8 carbons, at least 10 carbons, or at least 12 carbons) and typically not greater than 28 carbons (for example not greater than 26 carbons, not greater than 24 carbons, or not greater than 22 c