70 Percent Alcohol Works Better Than 91 Percent - 30 Second Hand Washing Works Best

Health workers who use hand sanitizer between patients may be more likely to spread flu germs than those who take the time to wash their hands, the higher the alcohol content in the sanitizer the less effective it is. Here's why?

According to Dr. Elizabeth Scott, professor of microbiology at Simmons Center for Hygiene and Health in Home and Community at Simmons University in Boston, higher-percentage alcohols are more concentrated. That means lower percentages, like 70 percent, have more water in them. Turns out, the water is actually an important ingredient here. 

Basically, a 90 or 91 percent alcohol solution is too powerful in some cases: It fries the outside of the cell before it can get into the inside and kill the actual germ. 70 percent alcohol is just the right proportion of water and alcohol to zap the entire cell.“Seventy percent alcohol has some water in it that allows it to cross a cell membrane, to really get into the bacteria to kill them,” Scott says.

Interestingly, Scott explains this rule of thumb only applies when you’re attempting to fend off bacteria. Alcohol’s effectiveness against viruses depends on the unique virus. Viruses with an envelope structure—including the flu virus, the common cold, HIV, and the new coronavirus—can be can be deactivated by alcohol solutions (like hand sanitizer) of 60 percent or more, while others like norovirus won’t be effectively targeted by any concentration of alcohol. 

Hand-washing helps to physically remove every type or virus and bacteria from your hands, and is an important part of any hygiene routine.

That’s because fresh mucus from infected patients interferes with the ability of the alcohol in hand sanitizer to reach the concentrations needed to deactivate the flu virus, researchers report in the journal mSphere. 

Flu virus in wet mucus from infected patients wasn’t destroyed after two minutes of exposure to sanitizer — it took about four minutes for the virus to be completely deactivated. That compares to just 30 seconds with handwashing.  

How to Use Rubbing Alcohol in the Kitchen

• Wipe down countertops to remove fingerprints.
• Use it to clean your phone and tablet screen.
• Wipe down windows and the glass on your oven door to remove stains, dust, and fingerprints.
• Clean doorknobs, cabinet knobs, light switches, appliance handles, and other germ-y hot spots that get touched often.
• Wipe down refrigerator shelves.
• Clean your microwave (inside and out). 
• Add it to a spray bottle diluted with water (in a 1:3 ratio of rubbing alcohol to water) and use it as an all-purpose cleaner.