Since the outbreak of the novel coronavirus known as COVID-19, there have been persistent (and celebrity-driven) reminders to wash our hands properly: soap and water, at least 20 seconds, single-use paper towel to dry, done.
Although alcohol-based hand sanitizers are fine in a pinch (if you can even find a bottle these days), we’ve often been told that hand washing is the preferred method to rid our hands properly of harmful bacteria and viruses.
But why, though? Shouldn’t that claim of “kills 99.9% of germs” plastered on hand sanitizer bottles be enough?
Yes and no.
Since we’re all pretty much stuck at home these days, now’s the perfect time to learn the science behind why washing your hands is better than hand sanitizer—and who is a better professor than everyone’s favorite food nerd, Alton Brown?
As the host of Good Eats, Brown is used to breaking down the often complex science of cooking.
Interestingly enough, hand washing is a lot like making salad dressing.
As Brown explains, lathering up with soap and water releases amphiphiles, a chemical compound possessing both hydrophilic (water-loving) and hydrophobic (water-hating) properties. Meaning that with proper agitation, amphiphiles create an emulsification that can hold things together that don’t naturally mix (for instance, oil and vinegar, aka salad dressing). This emulsification not only lifts and removes viruses from the skin, but it also can break down their fat-like coating, “leaving the virus feeling naked and afraid and mostly dead,” as Brown explains.
Alcohol-based sanitizers can kill viruses, but they don’t have emulsifying properties to remove the viruses or reach them all as soap and water can. Oh, and pro tip: Anti-bacterial soap isn’t necessary.
Watch Brown’s video below to get the full breakdown: