Why Do My Jeans Smell?

Most of us can’t resist the allure of trendy and trendy jeans. On average, almost anyone has more than 10 pairs of jeans in their lifetime. But jeans always have such a weird and unpleasant smell from the moment you walk into any Levi’s, Strauss, or Wrangler store.

Once upon a time, I was fascinated with the smell of new jeans because it was as unique and special as the smell of real leather, and I always inhaled these delightful scents. But the true story behind it is completely different.

The smell of new jeans comes largely from the chemicals used in the dyeing and processing of raw denim. Unfortunately, they are both harmful to humans when inhaled for long periods of time. Sounds disappointing, doesn’t it? Luckily, I gave up smelling new jeans a long time ago.

As you may have noticed, some jeans have a stronger scent than others. Heavy jeans will have a stronger smell than light jeans, and colored jeans will often smell like rotten eggs. But most of them will smell very bad right from the start.

If you are wondering why these smells happen, this article is just for you.

Let’s dive in!

Why do my jeans smell?

Most new jeans have a rather distinctive, but not identical, smell. This means that some denim fabrics will have a strong burning smell, while others will have no odor at all.

This is due to the chemical content used in the fabric treatment and dyeing process. If this chemical remains on the fibers of the fabric for a long time, they will have a more unpleasant smell.

Here are the two main chemicals that cause odors in new jeans:

Smell jeans on the wooden floor

1. Chemical Formaldehyde

If your jeans smell like industrial chemicals and are a bit burnt, it could be due to formaldehyde, a colorless gas commonly used in embalming.

This chemical helps keep clothes wrinkle-free, charge-free, or color-fading even after repeated washing. It also means that the formaldehyde cannot be removed with all-round detergents and water. It can only be partially washed away.

This is a chemical commonly used in the anti-wrinkle treatment of denim fabrics. Under high temperatures and great pressure, the molecules of cotton fiber and formaldehyde blend together, helping the fabric to be flattened, reducing the formation of folds due to the force exerted on the fabric surface.

If the garment is not pretreated before wearing, or if the treatment is ineffective, this chemical remains on the jeans, resulting in the characteristic burning and pungent odor of the jeans fabric.

It also helps fight mold, bacteria, or mildew that sweat, moisture, and dirt can build up during wear.

New jeans don’t always have a distinct scent. However, formaldehyde is a toxic chemical that affects the health of the wearer. If you have sensitive skin, you may experience itching or rashes when wearing jeans that have not been washed.

To test new jeans for formaldehyde, you can rub hard in one corner of the pants. If there is an unpleasant smell, like the smell of a burning, it means that there is a lot of formaldehyde remaining.

This indicates an ineffective fabric treatment by the manufacturer, and I would not recommend purchasing such products. Conversely, if the formaldehyde smell is relatively mild after rubbing the fabric, there are a few ways you can deal with the chemical residue:

  • Method 1:

Soak new jeans in a baking soda solution and then wash them with mild soapy water.

Keep in mind that high concentrations of soap can fade denim quickly, so laundry detergent liquid will be more friendly to jeans than detergent powder.

Soak jeans into baking soda and soapy water

  • Method 2:

Take a damp amount of coffee grounds and rub them all over your jeans. Do not soak jeans in water containing coffee grounds because they have no effect at all.

You need to rub the damp coffee grounds directly onto the jeans. You should not use new, unused coffee grounds because they are colored and can accidentally cling to some denim, causing patches.

It is recommended to use a small amount of used natural coffee grounds.

Coffee grounds

  • Method 3:

Another way to reduce the formaldehyde smell of jeans is to soak them in a solution of white wine, or some sort of Asian white wine.

These solutions have a rather strong smell to remove the burnt smell of new jeans.

Don’t worry if your pants will smell like alcohol. Don’t worry, these solutions will disappear quickly after the jeans are dried. This is also a way to prevent mildew on clothes.


2. Dyes using sulfur compounds

Some traditional denim weaves will use the double weave method, which involves 1 white yarn and 1 blue yarn woven together. If your jeans are woven this way, the chances are they don’t smell really bad in the first place.

In addition, some manufacturers will dye jeans after weaving with different color tones. During this process, a sulfur chemical will be added to the dye to help it retain its color for a longer period of time and reduce the number of times it needs to be dyed.

In essence, dyeing using sulfur denim fabric dye is similar to dyeing using traditional pigments. The dye is also in an insoluble state, and people need more solutes to dissolve the dye. Using a liquid sulfur chemical makes it easier to dissolve the dye, which results in a higher dye density with less alkalinity.

Dyeing jeans

This dyeing method is more efficient and environmentally friendly. Using dye powder can take up to 4–12 times. Meanwhile, including sulfur in the dyeing process only needs 1-2 dyeing times to give the desired color.

This method tends to produce more colorful jeans than traditional dyeing.

As a result, the jeans will probably smell a bit rotten due to the sulfur.

They do not have a strong smell like formaldehyde, but will have a faint smell and will last forever. You can wash it with water a few times and let it dry naturally.

washing jeans

Keep in mind not to wash in hot water. The fabric will shrink. This method will not completely wash the chemical away, but it can effectively reduce the odor.

Besides, you can dry the wet jeans inside out under the sun. The UV rays are able to break down the chemicals that cause bad odors.

Why do my jeans smell musty?

If your jeans smell musty, the chances are you have been tossing them in a corner of your closet for a very long time. Now, the jeans begin to appear moldy, with mildew stains on the fabric surface, causing such a characteristic mildew smell. Most new jeans do not have a mildew smell; they usually have a burnt or slightly rotten smell.

moldy jeans

Therefore, the musty smell on jeans is the result of mold invading your pants, and they are becoming more and more crowded. The technique of removing mold traces from fabric is not simple. It is even more difficult on denim because of the thickness and heaviness of the material.

In addition, chemical mold stain removal can cause the color of jeans to fade quickly. The best way is to see a professional to handle it for you. If you can’t do anything else, you should dye your jeans black. This will help cover the mold perfectly. The musty smell will also be eliminated.

Sometimes your jeans may smell musty without any mildew on the fabric surface. This could be because you put your pants in a humid area where there is mold, or you have unfortunately washed your jeans with some moldy clothes in a washing machine. Unknowingly, the smell of mold has settled on the fibers of the fabric, creating this unpleasant smell.

If you are in this situation, you can soak your jeans in a 1:3 solution of apple cider vinegar and water. Then dry naturally. In addition, sprinkling baking soda all over the jeans also reduces the mildew smell on them.

Clean moldy jeans with apple cider vinegar

Why do my jeans smell sour?

There are some main reasons why your jeans smell sour.

First, this can come from your jeans not drying completely when exposed to humid weather. If you live in an area with little sunlight and a lot of rain, like Alaska, Hawaii, or Island County, you’ll likely need a dedicated tumble dryer to dry your jeans comprehensively.

Hanging jeans after washing and letting them air-dry may not be effective enough to get rid of the sour smell completely. If your jeans have started to smell sour and unpleasant, you should not machine dry them.

Because odors will still be left on the fibers even when dried. You should wash the jeans again with fabric softener and dry them in the dryer.

washing jeans

Second, your jeans probably haven’t been washed in a long time, creating an unpleasant sour smell.

It’s true that jeans don’t need to be washed every day. You can wash jeans every 3 days. But not washing jeans for a few weeks is way too much.

The scent of sweat, body odor, and food odors will cling to the fibers of the denim fabric. They will mix with the sulfur in the dye and create an unpleasant bad smell. You may need to wash your jeans right away with a mild detergent.

washing jeans

Keep in mind to dry them properly with a cloth dryer to ensure that bacteria and mold are completely removed.

The third reason could be an overloaded washing machine and you haven’t put enough fragrant detergent to clean all of your clothes. Then when the process is over and you take the wet clothes out of the machine, they often smell very sour and steamy.

You may need to re-wash all clothes with a greater amount of detergent and then dry them thoroughly in the sun.

Why do my jeans smell bad even after washing?

One thing you may need to understand is that the smell of jeans will never be completely eliminated. As explained above, the smell of jeans can come from formaldehyde and sulfur chemicals in the rough fabric treatment or body odor left on the fabric.

Mold and body odor on denim can be eliminated by washing and drying, but the smell of denim chemicals will never go away. These chemicals need to be deposited to keep the fabric color from fading and wrinkling during use. After many washes and uses, this odor can be reduced.

But they will never go away. If this makes you really uncomfortable, you should look for light-weight jeans made with less dye. The heavier and thicker the jeans, the more chemicals will be needed for the color and wrinkle treatment.

Some last words

Jean smells are a unique part of this material, aside from the classic blue tones, five pockets, and heavy weave of these items. Odors from chemicals can be reduced after each wash and dry.

If this is too bad, you can do some of the DIY at home mentioned above. Overall, life is too short to not wear jeans!

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