Why is hot water more effective than cold when washing your hands, if the water isnt hot enough to kill bacteria?
In: Chemistry
For the purposes of hygenic cleaning (killing germs, removing dead skin, cleaning a wound), temperature doesn’t matter and (in some scenarios eg washing off bodily fluids or with certain soaps.) cold water is actually preferable.
For the purposes of cosmetic cleaning (washing off stains, cleaning oily fingers, greasy marks), hot water can help soften long chain hydrocarbons like waxes, grease or oils and can help solubilise inks or other chemicals into the soap or water.
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Tl;dr (Better ELI5) is:
If you want to kill germs, temperature doesn’t matter. If you want to clean dirty hands, warm water can help.
In both cases, washing thoroughly (at least 15 seconds) with soap is the most important thing.
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