Total fatty matter (TFM) is one of the most important characteristics describing the quality of
soap
Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are use ...
and it is always specified in commercial transactions. It is defined as the total amount of fatty matter, mostly
fatty acids
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...
, that can be separated from a sample after splitting with
mineral acid
A mineral acid (or inorganic acid) is an acid derived from one or more inorganic compounds, as opposed to organic acids which are acidic, organic compounds. All mineral acids form hydrogen ions and the conjugate base when dissolved in water.
Cha ...
, usually
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
. The fatty acids most commonly present in soap are
oleic,
stearic and
palmitic acids, and pure, dry, sodium oleate has TFM of 92.8%, while top quality soap noodles, now increasingly used for making soap tablets in small and medium-sized factories, are typically traded with a specification of TFM of 78% min., moisture 14% max. But besides moisture, finished commercial soap, especially
laundry soap
Laundry detergent is a type of detergent (cleaning agent) used for cleaning dirty laundry (clothes). Laundry detergent is manufactured in powder (washing powder) and liquid form.
While powdered and liquid detergents hold roughly equal share ...
, also contains fillers used to lower its cost or confer special properties, plus
emollients
A moisturizer, or emollient, is a cosmetic preparation used for protecting, moisturizing, and lubricating the skin. These functions are normally performed by sebum produced by healthy skin. The word "emollient" is derived from the Latin verb ''mo ...
,
preservatives
A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by ...
, etc., and then the TFM can be as low as 50%.
Fillers
In processed animal foods, a filler is an ingredient added to provide dietary fiber, bulk or some other non-nutritive purpose.
Products like corncobs, feathers, soy, cottonseed hulls, peanut hulls, citrus pulp, screening, weeds, straw, and cere ...
, which are usually dry powders, also make the soap harder, harsher on the skin, and with a greater tendency to become'mushy' in water, so low TFM is usually associated with lower quality and hardness. In the past, and still in some countries today, soap with a TFM of 75% minimum was called Grade 1, 65% minimum was called Grade 2, and less than 60% was called Grade 3.
External links
Soap Making InstructionsTFM should be 75% to 100% is referred as Grade 1 soap.
Soaps
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