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Of all the raw denim care myths, freezing your jeans is among the most persistent.
The premise here is a flawed idea that low temperatures remove unwanted odours in your jeans (and other clothes for that matter) by killing the bacteria that cause the smell.
We’re talking about bacteria that amass as sloughed skin and dirt ends up in your jeans when you do not wash them. And these bacteria thrive at the temperature of the human body.
But some bacteria can survive even very low temperatures, Stephen Craig Cary, who’s expert on frozen microbes, explains in the Smithsonian. What’s more, it takes only one survivor to repopulate your jeans when they warm up again.
Victor aka @selvedge1 on Instagram explains the science of body odours:
“The source of the smells in body odour is skin gland secretions and bacterial activity. Many of these secretions are broken down by bacteria into molecules that we recognise as body odour,” Victor says.
These molecules transfer into the cotton fibres in denim when you sweat,” he adds. “And freezing does not remove the molecules already embedded in the denim fabric.”
Freezing can temporarily reduce bacterial counts, but it does not remove sweat and other residues from the denim. Danny Hodgson from Rivet and Hide isn’t one to tell you what you should or shouldn’t do with your jeans. But he’s experienced himself how the freezing works only until the jeans defrost and the bad odour returns.
The research supports the same practical advice: when your jeans need cleaning, wash them rather than putting them in the freezer.
What the Research Found
In a 2019 University of Alberta master’s thesis, Mariko Wakefield compared freezing, ironing, UV exposure and washing. Six volunteers wore raw denim fabric samples against their skin for 24 hours before the treatments were tested.
Freezing initially reduced the number of bacteria recovered from the fabric, but the counts increased again over the following 24 hours. Washing brought the counts below the study’s detection limit, where they remained at the 24-hour check.
This was a small experiment using fabric samples, not whole pairs of jeans worn for months. It measured bacteria, not odour or fades. The result still reinforces the point: freezing is no substitute for washing dirty denim.
The bottom line is that freezing your jeans is not the same as cleaning them. For that, you need water and a suitable detergent. For practical advice, see my jeans washing guide.
MYTH STATUS: BUSTED