Bramble Berry Lye Calculator

Calculator Form

Example Data Table

Formula Used

Full sodium hydroxide lye: oil weight × sodium hydroxide SAP value.

Full potassium hydroxide lye: oil weight × potassium hydroxide SAP value.

Discounted lye: full lye × (1 − superfat percentage ÷ 100).

Purity adjusted lye: discounted lye ÷ (purity percentage ÷ 100).

Water as percent of oils: total oil weight × water percentage ÷ 100.

Lye concentration water: dry lye × (100 − concentration) ÷ concentration.

Water to lye ratio: total dry lye × selected ratio.

Batch weight: oils + dry lye + water + fragrance + additives.

How To Use This Calculator

1. Enter a recipe name and choose your weight unit.
2. Select the alkali type for bar soap, liquid soap, or a blended alkali recipe.
3. Enter the superfat percentage you want for the batch.
4. Choose the water method that matches your recipe style.
5. Add oil weights in the oil entry table.
6. Use custom SAP values when a supplier gives specific numbers.
7. Press the calculate button and review results above the form.
8. Download the CSV or PDF after checking every value.

Safe Soap Planning

A lye calculator helps turn a recipe idea into measured values. It does not replace testing. It also does not replace careful handling. Lye is caustic. Water heats quickly when lye is added. Work slowly, wear gloves, and use strong ventilation.

Why Oil Weights Matter

Each oil needs a different amount of alkali. This need is called the SAP value. Coconut oil uses more lye than olive oil. Jojoba uses far less. A mixed recipe must total the separate lye needs for every oil. That total is then reduced by the chosen lye discount, often called superfat.

Water Choices

Water does not saponify oil. It dissolves the alkali and controls how the batter behaves. More water can give more working time. Less water may trace faster and cure sooner. This calculator supports water as percent of oils, lye concentration, or water to lye ratio. These methods describe the same solution from different views.

Advanced Recipe Checks

Advanced makers often compare hardness, cleansing balance, and cure behavior. This tool focuses on the numbers needed before mixing. It reports total oils, alkali, water, fragrance, additives, lye solution strength, and final batch weight. It also shows each oil contribution. That makes errors easier to spot before the batch starts.

Responsible Use

Use trusted SAP values from suppliers or reliable references. Different lots can vary. Small rounding changes can matter in tiny batches. Always run important recipes through more than one trusted calculator. Label your oils clearly. Weigh with a scale that matches your batch size. Add lye to water, never water to dry lye.

Better Batch Notes

Good records improve future soap. Save the CSV after each calculation. Write down oil brands, temperatures, mixing time, mold type, and cure results. A recipe that looks correct on paper still needs observation. With careful notes, you can adjust water, superfat, or oil balance for the next batch.

Common Mistakes To Avoid

Do not swap sodium hydroxide and potassium hydroxide without recalculating. They use different SAP numbers. Do not guess purity. Old KOH often contains water, so the needed weight rises. Avoid volume measurements. Cups and spoons are not accurate enough for soap work. Review every entry before heating oils or preparing solution.

FAQs