Such or so?

Such is a determiner; so is an adverb. They often have the same meaning of ‘very’ or ‘to this degree’:

Those are such good chocolates.

Those chocolates are so good.

We use such + noun phrase and so + adjective or adverb phrase:

She is such a great cook.

Not: She is so great cook.

That was so unpleasant. (so + adjective)

Not: That was such unpleasant.

Why do you drive so fast? (so + adverb)

Not: Why do you drive such fast?

So but not such can also be used in front of much, many, little, few to add emphasis:

So much food was wasted every day.

Not: Such much food was wasted …

In those days there were so few doctors in our area.

Not: … there were such few doctors …