From a guy who calls himself 'The Coffee Detective':

"Coffee is best served at a temperature between 155ºF and 175ºF (70ºC to 80ºC). Most people prefer it towards the higher end, at about 175ºF.

Do you remember that lawsuit that MacDonalds lost when a customer scalded herself after she spilled some of her coffee? Back then the MacDonalds manual for its employees stated that coffee should be served at "195 to 205 degrees and held at 180 to 190 degrees for optimal taste."

As they discovered when they lost the case, that was too hot.

You won't go far wrong at 175ºF. That said, there are some coffee experts who like to drink their coffee at much lower temperatures."

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Two weeks ago, my sister burned her mouth on MacDonald's coffee after putting two creamers in it. The manager criticized her for not putting ice in it, and she said, "We keep our coffee at 200 degrees."

MacDonald's doesn't seem to have learned anything. Food is supposed to be good for you, it's not supposed to hurt you.