Difficult question and it makes me hungry! Crunchy means that when you bite into something, there will be a noise. To think of crispy, think of fried foods. For example, "I bit into the crispy fried shrimp and it made a crunchy sound." To crunch means that two things are pushed really closely together and make a noise. Crispy usually refers to food and means it's cooked to the opposite of soft.

crunchy is often used about things that are fresh for instance crunchy carrot. crispy is often used about things that have been cooked in thin and brown slices. both crunchy and crispy things have a soft noise.

http://www.ldoceonline.com/dictionary I hope it will help. Have a nice weekend!