Hot or cold water: What’s best for handwashing?

Have you always thought hot water was better than cold water at washing away germs? Well, you have been wrong all along.

A new study, published in the Journal of Food Protection, found that cold water was just as good as hot water at removing bacteria — so there is really no need to keep that geyser running and in turn ramping up your electricity bill.

Rutgers University in New Jersey conducted the study where 21 volunteers’ hands were exposed to harmless bacteria and then washed at various temperatures (at 15.5 degree Celsius, 26 degree Celsius and 38 degree Celsius) with varying amounts of soap. Researchers discovered that the temperature or the quantity of soap didn’t make any difference to the amount of harmless bacteria removed by washing the hands for ten seconds.

However, not everyone is convinced. There are experts who believe warm water presents the right conditions for the soap to work properly. Contrary to popular perception, regular soaps don’t kill germs. A vigorous scrub with soap loosens germs attached to the hands and the water washes them out easily. It’s the act of washing off the soap that removes germs from the hands. 

So the takeaway from the study is make sure to wash your hands before cooking and after using the washrooms without taking the temperature of the water used into consideration. And it should be a thorough wash covering the finger tips, thumbs, between the fingers, palms and back of the hands.