Cold Press Soap Planning Guide
Cold press soap needs careful measurement. Oils and sodium hydroxide must meet in a controlled ratio. This calculator helps you prepare that ratio before touching materials. It does not replace safety practice, but it gives a strong recipe draft.
Why Accurate Lye Matters
Each oil has a saponification value. That value tells how much sodium hydroxide is needed for one gram of that oil. Coconut oil needs more lye than olive oil. Shea butter needs a different amount again. When several oils are blended, each oil must be calculated separately. The totals are then added.
Superfat and Purity
Superfat leaves extra oil in the finished bar. Many makers use five percent. A higher value can make a milder bar. Too much may soften the soap. Lye purity also matters. If your flakes are ninety eight percent pure, you must weigh slightly more material. The tool adjusts the final lye amount for that setting.
Water Choices
Cold press recipes often use a lye concentration or water as a percentage of oils. Lye concentration compares lye weight with lye solution weight. Water percent compares water with total oils. Both methods are common. Pick the method that matches your recipe notes.
Fragrance and Additives
Fragrance is usually based on total oil weight. Additives can include clay, sodium lactate, sugar, colorants, or botanicals. Use supplier limits for fragrance. Some scents speed trace. Some additives can scratch skin. Measure carefully and test small batches first.
Using the Results
After calculation, review the oil breakdown. Check the lye amount, water amount, and total batch weight. Export the result for your notebook. Print the PDF for your soap room. Keep the CSV with supplier records. Always wear gloves, eye protection, sleeves, and work in ventilation.
Better Batch Control
Consistent notes improve every batch. Record oil brands, temperatures, fragrance behavior, mold size, and cure results. Compare finished bars after four to six weeks. Adjust one variable at a time. That simple habit makes troubleshooting easier and safer.
Mold and Yield
Fresh soap fills molds by weight. Cured soap weighs less after water evaporates. Estimate bar count with your target cured weight. Leave extra space in molds for safe mixing and easier unmolding later.