the thing you have to remember is that the curve for liqud cooling changes in almost no way when adding something to it, so the time it takes for it to cool down is almost negligible
For instance if you were to add milk to a cup of tea first it would cool down slightly slower, but have a bigger initial drop, the graph itself doesn't change
More than anything else it's a mark on the quality of the barista really. Good art is a symbol that people know their shit and are more likely to give you a good coffee
It's one hell of a skill. I got put on barista in february, working a couple shifts a week, till I quit in june and I could only manage a heart that looked more like an arse
