Let’s just clear something up quickly. OK?
Palate: the roof of your mouth. Also your sense of taste. This is the one you usually want if you’re talking about how a beer tastes.
Palette: the thing a painter uses for mixing up colours. So, by extension, a range of colours available for use. Could then conceivably be used to describe e.g. the range of flavours available to a brewer given a certain set of ingredients. Of course if you did this things would get confusing pretty quickly.
Pallet: the wooden things used for transporting goods, e.g. cases of beer, from place to place.