Science

Sorry, Freezing Your Jeans Will Not Ungross Them

Your jeans in the freezer: It’s a recipe for shrinkage of the worst kind, plus it won’t do anything to clean your jeans despite Levi’s recommendation to do so.

Levi’s worries that its very existence is threatened by climate change, which could lead to scarcity of water to grow cotton and cause many other bad things. So company execs are administering all sorts of eco-efforts, which we heartily applaud. However, their recommendation to freeze your jeans to clean them — which is apparently practised by raw denim wearers, more on that below — whilst saving water won’t actually make them clean. Just cold.

That’s according to University of Delaware frozen microbes expert Stephen Cray, who was moved enough by the inaccuracy to email Smithsonian magazine from his post in Antarctica.

While some of your jeans’ germs might not survive the freezer, some will, because they’re hardy like that. They mostly come from you, and thrive at body temperature. So when you put on your frozen jeans and your warm body heats up those chilly germs (Cray says it only takes one survivor), they will repopulate and have a microbial party in your pants.

Levi’s spokeswoman Kelley Benander says the recommendation came from designers and denim afficianados, but that they didn’t have any science to back up how well jeans freezing works. “We think anything that gets consumers talking about greener laundry habits is a good thing.”

Levi’s did some research and found that making one pair of jeans uses up 3480 litres of water in its lifetime, which has three main phases: watering the cotton crop, washing the jeans after they’re dyed to create that lived in look, and, lastly, laundering them (which Levi’s says makes up 50 per cent of the environmental impact).

But raw denim is the exception. It’s not washed after it’s dyed, and devotees are determined not to wash their jeans. They crave personalisation of their garment from the nooks and crannies of their own body over long periods of wear, and washing would ruin everything. The raw fabric moulds to the wearers body, and in turn, abundant germs populate the fabric, which can go unwashed for a year or more. Gross?

Maybe, not really. Rachel McQueen, an assistant professor of human ecology at the University of Alberta with her student and raw denim fan Josh Le tested the number (and types) of microbes in his jeans after he’d worn them for 15 months straight without laundering. Then he washed and wore them for 13 days and they tested the microbial load again. The amount of bacteria after more than a year of wear versus just shy of two weeks were not all that different, leading him to believe he wasn’t as gross as he thought!

But I wondered if that could mean the jeans were actually filthy after 15 months, and laundering didn’t remove much bacteria, which would also make the bacterial loads at 15 months and 13 days similar. So I emailed McQueen. Her response:

We didn’t test the counts immediately after washing — yes it’s highly likely that not all bacteria is removed with the washing process — but most will have been. However, once Josh began to wear his jeans against his skin, soils and bacteria would have then begun to transfer from his body back onto the jeans. I would say that most of those bacteria still came from his body during those 13 days.

Josh also shook and aired out his jeans occasionally, which may have reduced the amount of skin and dirt — sustenance for microbes — stuck to the pants.

I emailed Julie Segre of the National Human Genome Research Institute, who studies the skin’s “microbiome” to find out if shaking and airing would be helpful for dirt/skin reduction in the fabric. Her response: “I don’t know. I wash my clothes with water and haven’t thought much about the options.” Well.

In any case, none of the microbes McQueen tested were dangerous, even the ones from the crotchal area — McQueen expected they might find E. coli or something similarly sinister. But the bugs were all benign.

So, raw denim peeps, did you know you’re saving the earth? You’re consuming less (buying new pants less often than most; you need to wear that one pair a lot to break them in), your designers didn’t waste water buy washing them repeatedly, and you’re rarely using water to wash them. And you’re not nearly as grody as I thought. [Smithsonian via BoingBoing; Image: Tobi]

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