Notes on cold process soap
The Craft
Cold process and hot process are both soapmaking: fats react with lye to make soap. Melt and pour is not. It is remelting a soap base a factory already saponified. The difference decides what you control, what you can add, and how long you wait.
Ingredients
Charcoal soap is sold as a detox. What activated charcoal actually does in a rinse-off bar, how it compares with other black powders, and which claims lack evidence.
Ingredients
Cosmetic clays differ in mineral type, swelling and ion-exchange capacity. Kaolin, pink, green, bentonite, multani mitti and rhassoul compared, with what is and is not proven.
Buying Well
Most bars do not wear out, they dissolve. Six habits that slow that down, from the soap dish to the cure, and why a handmade bar rewards them more than most.
Who writes this
The Rasa Theory is written by people who make cold process soap in India. Most of what is here began as notes to ourselves after a batch went wrong. Every claim links to a source, and tradition is never passed off as evidence.
What happens in the pot and on the curing rack: saponification, superfat, pH and time.
The Craft
True soap always tests alkaline, usually between pH 8 and 11. Here is why that follows from the chemistry, and what a bar sold as pH 5.5 actually contains.
The Craft
Superfat and lye discount are the same adjustment described from opposite ends. Here is the arithmetic, worked in full, and how to pick a number.
The Craft
Cold process soap needs about 4 to 6 weeks to cure, and olive-heavy bars longer. What changes during the cure, and how to tell when a bar is actually done.
The oils, clays and Indian botanicals that go into a bar, with tradition and evidence kept apart.
Ingredients
Manjistha is Rubia cordifolia, Indian madder, a red plant dye used in Ayurveda. What it does in a soap bar, why its colour shifts with pH, and what is tradition versus tested.
Ingredients
Tangedu (thangedu puvvu) is tanner's cassia in English, scientific name Senna auriculata. Telangana's state flower: what the plant is, its uses and the evidence.
Reading labels, judging a bar, and making the one you bought last.
Buying Well
Why a handmade bar often costs more: oil prices, weeks on a curing rack, retained glycerine, small batches and Indian licensing, with World Bank and Cosmetics Rules data.
Buying Well
How to read a soap label in India: INCI names like sodium olivate, TFM and BIS IS 2888 grades, Legal Metrology declarations, and which marketing words mean nothing.
