How to Use LyeLab
LyeLab helps you formulate safe, balanced soap recipes by calculating the precise amounts of lye and water needed for your chosen oils. Follow these steps to design your recipe.
Step 1: Select Your Lye Type
Choose NaOH (sodium hydroxide) for bar soap or KOH (potassium hydroxide) for liquid soap. When using KOH, you can adjust the purity percentage (default 90%) since KOH is typically sold at 90% purity.
Step 2: Set Weight of Oils
Enter the total weight of oils for your batch and select your unit (oz, lb, g, or kg). This is the total amount of oils before lye and water are added.
Step 3: Configure Water
Choose how to calculate water. The default is % of Oils at 38%, which is recommended for beginners. Advanced soapers can use Water:Lye Ratio or Lye Concentration % for more precise control.
Step 4: Set Superfat & Fragrance
Superfat is the percentage of oils left unsaponified, providing moisturizing properties. The default is 5%, which is a good starting point. A higher superfat makes a more conditioning bar but may reduce lather. Optionally set a fragrance rate (oz/lb or g/kg of oils).
Step 5: Add Oils to Your Recipe
Search and select oils from the oil list. Each oil contributes different properties to your soap. You can enter amounts as percentages or weights using the toggle. Your oil percentages should total 100%. Hover over oils in the search list to preview their individual soap qualities before adding them.
Step 6: Review Your Recipe
The calculator automatically computes your lye and water amounts, soap qualities, and fatty acid profile as you adjust your recipe. Use the View Recipe button to see a printable summary with weights in all units, or download as CSV.
Understanding Soap Qualities
LyeLab displays quality predictions based on the fatty acid composition of your oils. Each quality has a recommended range shown in parentheses. Values within range show a green checkmark; values outside range show an amber warning.
Fatty Acid Profile
Each oil is composed of fatty acids that determine the soap's properties. The fatty acid profile shows the weighted blend of all oils in your recipe, along with the Saturated to Unsaturated ratio.
Lauric — Strong cleansing with big bubbly lather. Found in coconut and palm kernel oils.
Myristic — Similar to lauric with slightly less cleansing power.
Palmitic — Adds hardness and creamy lather. Found in palm oil, tallow, and lard.
Stearic — Adds hardness and a stable, waxy feel. Found in tallow, cocoa butter, and shea butter.
Ricinoleic — Unique to castor oil. Adds bubbly and creamy lather plus conditioning.
Oleic — The primary conditioning acid. Found in olive oil, avocado oil, and sweet almond oil.
Linoleic — Conditioning but can reduce shelf life at high percentages. Found in sunflower and grapeseed oils.
Linolenic — Similar to linoleic. Found in hemp oil and flaxseed oil. Use sparingly to avoid rancidity.
The Sat:Unsat ratio gives a quick view of your recipe's balance. A higher saturated ratio makes a harder, longer-lasting bar; a higher unsaturated ratio makes a softer, more conditioning bar.
Getting Started with Soap Making
There are two main methods for making soap from scratch: Cold Process (CP) and Hot Process (HP). Both use the same ingredients — oils, lye (NaOH), and water — but differ in how saponification happens.
Cold Process (CP) Soap
- Place your oils in a stainless steel or enamel pot and heat until melted and combined.
- Carefully mix your lye into water (never water into lye) and let cool.
- Add the lye solution to the oils and stir (or use a stick blender) until the mixture reaches "trace" — a light pudding-like consistency.
- Add fragrance and colorants, then pour into a mold.
- Insulate and let harden for 24–48 hours, then unmold and cut into bars.
- Cure for 4–6 weeks before use to allow saponification to complete and excess water to evaporate.
Hot Process (HP) Soap
- Follow steps 1–3 of the Cold Process method.
- Instead of molding, cook the mixture on gentle heat (crock pot or double boiler) for 1.5–2 hours, stirring occasionally.
- The soap goes through stages (separation, gel, mashed potato texture) until it reaches a translucent, vaseline-like consistency.
- Spoon into molds, let cool for several hours, then unmold and cut.
- HP soap can be used sooner since saponification is essentially complete, but still benefits from a short cure for a harder bar.
Lye (NaOH/KOH) is a strong caustic alkali that can cause severe burns. Always wear safety goggles, gloves, and long sleeves. Work in a well-ventilated area. Always add lye to water, never water to lye. Keep vinegar nearby to neutralize spills. Read comprehensive lye safety guides before your first batch.
Helpful Resources
There is a wealth of beginner information available online from experienced soap makers. Here are some recommended starting points:
- Wikipedia: Soap — Broad overview of soap chemistry and history
- Miller Soap — Comprehensive soap making resource
- SAP (Saponification Value) is the amount of lye needed to fully saponify a given oil. Each oil has a unique SAP value. LyeLab uses average SAP values from multiple sources since natural oils vary between batches.
- Start with a simple 3-oil recipe: olive oil (base), coconut oil (cleansing/lather), and palm oil or shea butter (hardness).
- Use 5% superfat until you gain experience.
- Use 38% water as percent of oils for your first batches.
- Always run your recipe through a lye calculator before making soap — never guess lye amounts.
- Keep a detailed soap journal to track what works.
Note: SAP numbers used in LyeLab are averages compiled from various sources. Natural oils can vary between batches and suppliers. Always superfat your recipes as a safety margin.