For reasons of expense or availability, almond, brazil, cashew, hazelnut, macadamia, pecan, pistachio, walnut, or even peanuts are sometimes substituted for the traditional pine nuts. Also, while the nuts are traditionally used as is, some recipes call for prior toasting or roasting. While not preferable, other culinary nuts may be used due to the taste disturbances that some people may experience after consuming pine nuts (see pine mouth). Many online recipes in English for pesto will also list black pepper or white pepper among the ingredients, which the traditional Genoese recipe omits.