"Amarillo" is spanish for yellow, the peppers ripen to a bright orange. Traditional recipes for amarillo sauce actually call for blanching all heat from the peppers before use. Im growing Aji cristals this year for making "Aji Verde", I have two pods that Im ripeing for seeds and they are taking forever. Six weeks and the shoulders have barely turmed. My experience with "Aji"s in general is that they arent really suited for most general applications( sauce, cooking). they tend to be overly sweet or underwhelming.