Total Fatty Matter (TFM) is one of the most important characteristics describing the quality of soaps and it is always specified in commercial transactions.
It is defined as the total amount of fatty matter, mostly fatty acids, that can be separated from a sample after splitting with mineral acid, usually hydrochloric acid. The fatty acids most commonly present in soap are oleic, stearic and palmitic acids and pure, dry, sodium oleate has TFM 92.8%, while top quality soap noodles now increasingly used for making soap tablets in small and medium size factories, are typically traded with a specification TFM 78% minimum, moisture 0f 14% maximum. But besides moisture, finished commercial soap, especially laundry soap, also contains fillers used to lower its cost or confer special properties, plus emollients, preservatives etc., and then the TFM can be as low as 50%.
How your soap affects your well being? Higher TFM ensures that soaps are least harmful to the skin and do not cause dryness; in “bathing” bars.
Less TFM means very harmful soap, that soap will grasp all the moisture present in the skin making it dry. As skin becomes dry it may become more sensitive and prone to rashes, infections and skin breakdown.
Bathing soaps are classified into three grades:
- Grade 1: soaps should have 76% minimum TFM
- Grade 2: soaps should have 70% minimum TFM and
- Grade 3: 60% minimum TFM.
For laundry soaps, they are classified in two grades.
- Grade 1: 62% minimum TFM and
- Grade 2: 50% minimum TFM
Simply put, higher the Total Fatty Matter (TFM) of soap better is its cleansing ability.