How often should jeans be tossed into the washing machine?
On Tuesday, Chip Bergh, CEO of Levi Strauss & Co. mentioned that more than a year had passed since he washed the very pair he was wearing as he spoke at Fortune’s ‘Brainstorm Green’ conference on sustainability. He said leaving the jeans out of the laundry saves water and suggested too much washing breaks down the denim.
"These are one of my favorite jean, maybe a year old, and they have yet to see a washing machine," Bergh said proudly. "If you talk to real denim aficionados, they’ll tell you, don’t wash your blue jeans.”
The statement has gotten people talking until they're blue in the face, or, as the Daily Beast put it, "people are freaking out."
Washing denim has long been hotly debate, but it's hard to disagree with the Daily Beast, which concludes "...less wash equates to retaining the denim’s color, size, and shape.
WCCO used its "Good Question" franchise to get to flesh out the question. Their expert, Mall of America trend specialist Sara Rogers, told the station it's a good idea to "...go ahead and throw them in the washer, but not too often."
“For most people probably every two months is good,” Rogers said.
Some jeans research exists. A 2011 study at the University of Alberta compared bacteria levels on a pair of jeans not washed for over a year with a pair washed after almost two weeks, and found that they were practically identical.
“I was pleasantly surprised,” professor and researcher Rachel McQueen said. “What I found was just normal skin flora. The counts were really, really similar. The bacteria load from the swabbed areas were pretty much the same.
What about freezing jeans as an alternative to washing them? Some jeans come with care tags that advise freezing. ApartmentTherapy has a home hacks post with a confessional from a jeans wearer who was told to stick a new pair of spendy jeans in the freezer when they would have ordinarily gone into the washing machine. (The pants were first popped into a freezer bag.) The advice said that it would take a week in the freezer to get them clean.
"Personally, after taking my jeans out this morning, I have to say they did feel crisper, though it may simply have been the cold," the jeans owner said. "I can't say I was fooled into thinking that they had been washed in any way, BUT they did - after all that time away from me - feel fresh."
But Vox.com said freezing is bunk. "Washing the denim kills bacteria, as does raising its temperature to extremely high levels," the story said. "But freezing a pair of jeans, alas, is not likely to kill all the bacteria on them." (That bacteria is what gets stinky.) The story goes on to say that while freezing might kill most of the bacteria, if some remain, "they'd likely be able to recolonize the denim quickly after it warmed back up. That's because the dirt and dead skin cells present in the jeans...are left entirely intact by freezing."
More jeans science: "We freeze bacteria at -20 or -80°C and can then regrow them," says Julie Segre, a researcher at the National Human Genome Research Institute who studies the bacteria that live on human skin.