Fragrance-free or odourless laundry detergent?

When I was sitting in a full bus one day, the person sitting opposite me asked the person sitting by the window to change places with her. In a full bus, it wasn’t possible to change to a place further away. She had started to cough and sneeze, because someone wearing strong perfume was standing next to her. The same kind of reaction might have been caused by a strong laundry detergent fragrance from clothing. After moving to the window seat, she thanked the other passenger and said she had severe multiple chemical sensitivity. 

Multiple chemical sensitivity is a reality in our daily lives, and it’s quite common these days. According to the Finnish Allergy, Skin and Asthma Federation, 10 to 40 % of the population suffer from multiple chemical sensitivity. Because of this, the demand for mildly scented and fragrance-free products has increased. Sometimes, even a mild fragrance is too much, in which case it’s best to choose a fragrance-free product. But what is actually expected of a fragrance-free product? Can the product have a scent of any kind, or is it assumed that a fragrance-free product doesn’t really have an odour?

A completely odourless product is hard to find, because the ingredients usually have their own scent. Soaps and other surface-active agents especially give fragrance-free products their typical scents. Some ingredients may cause a tangy or stale odour, and some make the product smell nice, fruity or fresh. If, for example, a detergent containing chlorine has been used, the product may emit a strong chlorine odour even though the product has been labelled fragrance-free. When products are labelled fragrance-free, people with fragrance allergies are able to find a suitable product. For someone with multiple chemical sensitivity, however, this isn’t necessarily the whole truth. As a product developer, I need to examine the scent of single ingredients, as well as the way ingredients affect each other’s scents in the final product. Sometimes, even small changes can result in a completely different overall fragrance.

Are we actually looking for a product that doesn’t leave fragrance residues in textiles after washing? Do we accept a fragrance-free product if some ingredients smell a little fruity and cover the smell of other, bad-smelling ingredients? The scent of laundry detergents is usually modified with fragrances. Laundry detergent fragrances are compounds that are intended to adhere to textiles and release perfume even after washing. Fragrances can also be used to create false impressions of cleanness. With mildly scented products especially, one sometimes hears the question, “Will my laundry be clean without any fragrance?” Mildly fragrant surface-active agents are not intended to stick to textiles. They work in the washing process by detaching dirt and are rinsed away from textiles with water. This property could also be used when monitoring the rinseability of detergents from textiles or evaluating the amount of rinsing water used. If the laundry still has a fruity scent when taken out of the washing machine, the detergent hasn’t been rinsed off properly. These compounds enable the modifying of the product’s own scent without affecting the fragrance of clean laundry.

For the moment, we know little about the way multiple chemical sensitivity works, so it’s hard to judge whether a fruity surface-active agent, for example, would cause the same allergic reactions in sensitive people as a fruity fragrance. Do multiple chemical-sensitive people react to certain chemicals or to a certain type of fragrance? Because of this, fragrance-free products are made to be as odourless as possible, thus avoiding any impression of the product’s fragrance. This way, buyers of fragrance-free products aren’t disappointed if they were actually looking for an almost odourless product.

A fragrance-free product clearly isn’t a simple concept. When you buy a fragrance-free product, you can expect one of the following product types: an odourless product that has no added fragrance and contains either odourless ingredients or ingredients that cancel each other’s odour; a mildly scented product that has no added fragrance but contains ingredients that create the scent typical of the product; a pleasant-smelling product that has no added fragrance, but whose normal scent has been covered with pleasant-smelling compounds not classified as fragrances. This means that when you buy a fragrance-free product, you can’t always assume you’ll get an odourless product. Should dry laundry have some residual fragrance in the first place, or can fragrances in laundry detergents be completely replaced by mildly pleasant-smelling surface-active agents or similar compounds in the future?

Tomi Peltonen
Product Development Chemist
KiiltoClean Oy