The smell of leather
Everyone knows the soothing scent of old leather, but nowadays there are hardly any leathers that exude this beautiful smell. This is due to the fact that leather was tanned differently in the past. Vegetable tanning was then the main tanning method. The tanning agents and fats and oils gave the leather a special odour. Some of the odoriferous substances used in the past are even prohibited today. In particular, some nitro-musk compounds which strongly influenced the smell of leather.
Today, most car, furniture and clothing leather is chrome tanned. This tanning method is less odour intensive. Also there is more than one leather smell. Depending on the refatting substances, dyeing and colour chemicals and many other substances used, the resulting leather smells differently. Consequently, the mixture of individual odours of the substances gives the final smell of the leather.
Most automotive manufacturers attach great importance to having as little odour as possible, also referred to as new car smell. For testing, the interior of a vehicle is heated to 70 ° C, as odours intensify with rising temperature. Experts with particularly sensitive noses then test the interior for strong and unwanted odours. Most manufacturers prefer an odour-free interior so as to avoid complaints.
The smell policies of the various manufacturers (2015) are as follows:
- VW: "Leather seats must smell like leather."
- BMW: "The best smell is no smell."
- Mercedes Benz: "Leather is the only permissible smell."
- Volvo: "Minimize all odours."
- Audi: "Neutral smell."
- Ford: "Target: Eliminate all odours."
Since many consumers believe that a leather smell is pleasant, it has long been investigated how to control the smell during the production of leather. However, since the leather smell is produced by a mixture of the tannins, refatting agents, dyestuffs, binders and preservatives used in the production process, the final leather odour cannot be controlled. Most chemical components are necessary to achieve the desired leather quality. If an element is exchanged for a certain smell, the quality parameters of the leather are often changed too.
Micro hollow balls
There have also been attempts to introduce odours into the leather or the dressing via micro-hollow balls, which give a leather odour under load. Such micro hollow balls contain smell and crack under weight over time. So far, leather produced in this way is not widely used in the market.
Alternatively, it is possible to apply a leather odour like a perfume to the final product.
Odour problems with new leather
Some new leather bags, belts, furniture, vehicles and jackets have a very unpleasant smell. This can occur when inferior fish oils or other foul-smelling substances were used in the manufacturing process. This should be noticed at the time of purchase. Usually, the smell occurs later, because odours are only noticeable at warm temperatures or in smaller, neutral-smelling rooms.
Unsuitable fish oils spread a "fish odour". In clothing, the leather may be saved by a dry-cleaning specialist, who removes the oil completely by cleaning with solvents. But, usually, the object suffers under this type of cleaning. Where such a cleaning is not possible, there is no solution. Therefore, always highlight such issues to the manufacturer or shop owner in good time.
Leather from North Africa sometimes smells of urine. This phenomenon occurs more frequently with low-priced goods. Unfortunately, this smell cannot be removed. Don`t buy such goods or complain immediately.
Around 2010 in Germany there was a considerable increase in cases where leather furniture (beds, upholstery, furniture) gave off a biting, chemical smell from the moment of delivery. In most cases, the leather originated in Italy. It is assumed the problem was due to a preservative which produces this strong and unpleasant odour. If a distinctive smell does not stop after a few days, you should seek advice.
Measuring leather smell
Unfortunately, you cannot measure smell. Opinions differ as to which is a nice or an unacceptable leather smell. In practice, the nose is used for testing. Since every leather smells like "leather", such a typical smell can`t be a cause of complaint. A good indication of whether a leather stinks unreasonably, is the response of human beings, who will confirm the unacceptability of the odour. Therefore it is not an individual sensitivity, but the majority who find the smell unacceptable. This is usually confirmed by an expert.
Mould and cellar stench
Unpleasant odours arise due to incorrect storage. Mostly it is mould. Be careful before buying used leather articles. The most beautiful vintage car or the most beautiful crocodile leather bag may be irreversibly worthless. Frequently, such odours cannot be eliminated.
Mouldy leather Leder