Whitepaper Fatty spew

How to avoid fatty spew on leather?

Download our free whitepaper on fatty spew and learn about its background, where it comes from, and what can be done to prevent its formation.

On processed leathers it is sometimes observed that, over time, an undesired white milky film appears on top of the leather. This white layer often gives rise to debates on its origin and causes, and in some cases leads to a claim for damages.

The phenomenon described is called ‘fatty spew’. The possible sources of fatty spew may be of diverse nature, they are similar in one respect. They always originate from high melting point substances.

Download the whitepaper ‘Fatty Spew’

What is fatty spew?

All fats have a tendency to migrate through the leather when they are not irreversibly fixed to the matrix. Free saturated fatty acids, as all other substances, are sensitive to the influence of temperature. One of temperature’s effects is that it can change a substance’s appearance. The reason for the white layer on the grain is the high melting point, which is about 60°C to 70°C for all of the substances causing fatty spew. Below this temperature they begin to solidify but remain undetectable to the eye.


Interesting for you

Discover more on Wet End
leather crafts

Wet End


Stay informed

Receive the latest company news and industry updates