Sodium lactate (60 % solution)
A harder bar that unmoulds sooner.
Opens the calculator’s starter recipe, 1000 g of oils, with this additive at the dose it fills in, ready to change.
What it is
Sodium lactate is a salt of lactic acid, sold for bar soap as a 60 % solution in water that is about a third heavier than water. It is fully neutralised, so it takes no lye.
Corbion primary source, Jungbunzlauer primary source
How much
- 1 tsp per pound of oils filled in Faiola, Soap Crafting primary source
- 1–3 % of the oils Classic Bells supplier or guide
- 3 % of the oils in hot process Soap Queen supplier or guide
The calculator fills in 1 tsp per pound of oils: 14.4 g for the 1000 g of oils in its starter recipe.
When and how
- Usually: into the lye solution.
- Also used: into the oils, after the cook.
Soap Queen supplier or guide, Faiola, Soap Crafting primary source, Classic Bells supplier or guide, Lovin Soap supplier or guide
What it does to the recipe
- 40 % is water, taken off the recipe’s water.
Corbion primary source, Jungbunzlauer primary source
Worth knowing
- Caution: Too much makes a brittle, crumbly bar. One source says that above 3 % it goes soft and rubbery instead. Faiola, Milk Soaps primary source, Classic Bells supplier or guide
Spoons and drops
- 1 tsp ≈ 6.56 g
- 1 tbsp ≈ 19.7 g
- 1 cup ≈ 315 g
Corbion primary source
INCI name
Sodium Lactate
- CAS number
- 72-17-3, 867-56-1
- EC number
- 200-772-0, 212-762-3
- As weighed
- Sodium Lactate 60 %, Aqua 40 %
Recipes that use it
Guides that discuss it
Sources
Corbion, PURASAL S/HQ60 sodium lactate for bar soap: "Increasing hardness of oil-based soap bars", "Enabling stamping and release from molds", "Reducing water-loss and cracking". PURASAL S safety data sheet: density 1320–1340 kg/m³ at 20 °C.
Jungbunzlauer, Personal Care folder (2025): sodium lactate, sodium citrate and sodium gluconate are "Fully neutralised salts"; sodium gluconate is "particularly adapted for mass market soap and bath products" and, in strongly alkaline solutions, "surpasses all other chelating agents, such as EDTA".
Soap Queen, "Sunday Night Spotlight: Sodium Lactate": "added to cooled lye water"; 3 % of the oils in hot process.
Anne-Marie Faiola, Soap Crafting (Storey, 2013): sodium lactate "is typically added to the lye-water at 1 teaspoon per pound of oils".
Classic Bells, "Sodium lactate": "10 to 30 g of SL solution per 1000 g of fats (1% to 3%...)"; "Over 3% can make bar soap softer and more rubbery"; powder remade as a 60 % solution from 6 parts powder and 4 parts water; the powder is "irritating if inhaled".
Lovin Soap, fluid hot process: sodium lactate into the cooled lye or "at the end when you add fragrance".
Anne-Marie Faiola, Milk Soaps (Storey, 2019): too much sodium lactate makes a "brittle, crumbly bar of soap" (p. 222); apple cider vinegar at trace "will quickly start to thicken the batter", and she writes that it lowers the pH.