For instance, I make myself some hot coffee and I want to turn it to iced coffee. Stirring it seems to cool it down much faster than letting the ice just sit in the coffee, however, from what I have read, stirring the ice melts the ice faster and more even though it cools it down faster. Why? Is this even correct?
Also, would the ice just sitting in the hot coffee melt roughly the same amount as the stirred once the coffees reaches the desired cold temperatures? Idk we can make one up, coffee from 160°f to 40°f, I guess. I also generally fill my coffee cup completely with ice as I’m sure the amount of ice changes this.
I hope this makes sense and I tagged the question correctly. Thank you,
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The rate of heat transfer is faster the larger the difference (delta) between the temperature of two objects of different temperatures. Ie. Hot coffee at 100°C and ice at 0°C will transfer heat faster than between coffee at 90° and water at 50°
If ice just sits there and melts, the water around the ice is close to the temperature of ice. If you wait for those molecules to diffuse through the rest of the coffee it will take a long time as it happens through what is called Brownian motion.
If you STIR the coffee, then you’re moving the ice, and the cold water from just melted ice, through the hot coffee, meaning the ice gets into contact with more of the hot 100°C liquid.
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