The peppermint tea should work, cold or hot, IF it is really strong of peppermint.
I agree that the ants are harmless and are helping aerate your soil. If they become a real nuisance, here are some thoughts about ant control:
One category is powdery things that clog up their spiracles (breathing pores), if they try to walk over them. This includes chalk line, baby powder, cleanser powder (like comet), bone meal. Make a ring of powder around what you want to keep them away from and they won't cross it.
Another category is strong smelling things, including vinegar, cinnamon, black pepper, cayenne pepper, bay leaves, peppermint oil or other mints, cloves, garlic. Sprinkle your strong smelling stuff on and around what you want to protect from the ants. (Be careful with the vinegar, don't put it on your plants, it can burn or even kill them, if directly on the plant)
Then there are ways to kill the ants if you are feeling more aggressive (they definitely don't like that): pouring boiling water down into the ant hill, diatomaceous earth around what you are protecting, boric acid powder, and theoretically, put a dish of raw cream of wheat out. Supposedly they eat it and it swells up inside them and they explode. For all I know this this one is an old wives tale, but it might be interesting to try... exploding ants!
Then people have suggested windex + ivory soap, Shakely's Basic H, and simple green. I'm not sure which category these fall in...