What is the difference between the grades of matcha?

Ceremonial Matcha is pure green tea leaves and is the most expensive and best consumed with just water (hot or cold). 

If making lattes or smoothies, a lower grade matcha will do the trick. Culinary matcha is great for cooking with and making latte art; it often includes fiber and sugar in the ingredients. 

Both ceremonial matcha and culinary matcha can be graded between bright green and brownish/bitter.