Questions & Answers about Le café est trop chaud, alors je vais attendre.
Le café means the coffee.
In this sentence, the speaker is talking about a specific coffee that is already there, so le makes sense.
- le café = the coffee
- un café = a coffee / a coffee drink
- du café = some coffee / coffee in a general substance sense
So if you are talking about the cup in front of you, Le café est trop chaud is very natural.