What is a water discount?

A water discount means using less water than the standard "full water" amount. Full water is typically 38% of oil weight. A 10% discount uses 10% less water. Less water means harder soap faster, less shrinkage during cure, and reduced chance of glycerin rivers.

What is lye concentration method?

Instead of calculating water as a percentage of oils, the lye concentration method sets the ratio of lye to total liquid. A 33% lye concentration means the lye solution is 33% NaOH and 67% water. This gives more consistent results across different recipes.

How much water discount is safe?

Beginners should use full water or a small 5-10% discount. Experienced soapmakers often use 15-20% discount or 33-40% lye concentration. Too little water can cause the soap to seize (harden too fast) or not mix properly.

Does less water mean the soap cures faster?

Soap with less water will unmould sooner and feel harder earlier, but the cure time (4-6 weeks) is about the same. The curing process is about crystal structure formation and pH reduction, not just drying.

CraftCalcs

Water Discount Calculator — Soap Water Amounts

Calculate water amounts using full water or water discount methods.

Total Oil Weight

Lye Weight

Calculation Method

Water %

Full water = 38%

How We Calculate This

How the Calculation Works

Oil percentage method: water = oil weight x percentage. Full water is 38%.

Lye concentration method: water = lye weight x (100 - concentration) / concentration. A 33% concentration with 68g lye gives ~138g water.

The water discount percentage shows how much less water you are using compared to full water (38% of oils).

Frequently Asked Questions

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Last updated: 2025-02-20

All calculations are estimates. Always verify quantities before purchasing materials.