"Ser to nie warzywo."

Translation: Cheese is not a vegetable.

[MountainAsh2]

Good to know.

[tryingveryhard]

Waiting patiently for the "mayonnaise is an instrument" question.

[AidanGiord]

Why "to" included instead of "jest"?

[Jellei]

There are two possibilities here, but in a limited context. A lot of people recently asked why cannot 'to' be used in a given sentence, so have a look here for example.

But this is quite a simple "X is Y" sentence with both of them being noun phrases (and it doesn't matter that Y is negated), and it can be written in both ways: "X to (nie) Y", with both of them being in nominative; and "X (nie) jest Y", (Ser nie jest warzywem), with X in nominative and Y in instrumental.

So the option with 'jest' must be definitely accepted, but it looks differently grammatically.

[PauloSanto801520]

Why does the Z sound like J in warzyvo? I thought it needed a dot above or an 'i' after it?

[alik1989]

[Rz] is a digraph which corresponds to [ż]. There are very few exceptions where those two letters are pronounced separately.