Set up a simple experiment. You'll need:
Originally Posted by herron0009
A cup of the appropriate sizeHeat the coffee. Pour the hot coffee into the cup. Put the thermometer into the coffee. Note the initial temperature. Then note the temperature at regular intervals - e.g. every half-minute or every minute.
A clock or watch with a second hand
Coffee, cream, sugar, etc
Write your results in a table with time in the first column and temperature in the second. This table, then, shows temperature as a function of time.
Optionally you could now plot a graph of the results, with temperature on the vertical scale, time on the horizontal scale.
Repeat the experiment several times with various combinations of additives: cream, sugar, etc. In order to start at the same temperature as before, you may need to heat up the coffee again after adding the additive(s) (e.g. in a microwave oven), since adding cream etc will cool the coffee. Start recording the results when the temperature is the same as the initial temperature as the first experiment.
Plotting the results on the same graph as before will allow a simple comparison to be made.
The 'best time' to drink the coffee is a very subjective thing. Many people like their coffee scalding hot - others prefer it practically cold. If you were serious about answering this question, you would need to enlist the help of a large number of coffee-drinking volunteers. Find the average optimum temperature, and then use your tables and/or graphs to determine the time for the coffee to reach this temperature.