Frequently Asked Questions
Common questions about soap making and using Soaply. Can't find your answer? Contact support.
Soap Making Basics
What is cold process soap making?
Cold process soap making is a method where oils and fats are combined with a lye (sodium hydroxide) solution at low temperatures. The mixture is stirred to trace, poured into molds, and left to saponify and cure for 4 to 6 weeks. Unlike hot process or melt-and-pour methods, cold process gives you full control over every ingredient and produces a smooth, polished bar.
Is lye dangerous? Can I make soap without it?
Lye (sodium hydroxide for bar soap, potassium hydroxide for liquid soap) is caustic and requires careful handling with gloves, goggles, and ventilation. However, all true soap requires lye. During saponification, lye reacts completely with oils and no lye remains in the finished bar. Melt-and-pour bases are pre-made soap that already went through this process, so you handle no lye yourself, but lye was still used to create the base.
What is trace in soap making?
Trace is the point where your oil and lye mixture has emulsified and thickened enough that drizzling soap batter across the surface leaves a visible trail or 'trace' before sinking back in. Light trace is thin like cake batter, medium trace holds a light pattern, and thick trace is like pudding. Most recipes call for light to medium trace before adding fragrance, color, and pouring into molds.
How long does cold process soap need to cure?
Cold process soap typically needs 4 to 6 weeks to fully cure. During curing, excess water evaporates, the bar hardens, the pH drops to a mild level, and the soap becomes longer-lasting. Some soaps with high olive oil content (like Castile soap) benefit from 6 to 8 weeks or longer. You can test pH with strips. A properly cured bar will be firm, mild, and produce good lather.
What is the difference between NaOH and KOH?
NaOH (sodium hydroxide) is used to make solid bar soap. KOH (potassium hydroxide) is used to make liquid soap or soft soap paste. They have different SAP (saponification) values, so you cannot substitute one for the other without recalculating. Some advanced recipes use a blend of both (dual lye) to create cream soaps or specialty bars. Soaply's calculator supports all three options.
Calculator and Lye
What is superfat and what percentage should I use?
Superfat (also called lye discount) is the percentage of oils that remain unsaponified in your finished soap. A 5% superfat means 5% of your oils will stay as free oils, making the bar more moisturizing and providing a safety margin against lye-heavy soap. Most soap makers use 3% to 8%. Lower superfat (2-3%) produces a harder, more cleansing bar. Higher superfat (7-10%) is more conditioning but may feel greasy or go rancid sooner. 5% is the most common starting point.
What is lye concentration and how does it differ from water discount?
Lye concentration is the percentage of lye in your total lye solution (lye + water). A 33% lye concentration means the solution is 33% NaOH and 67% water by weight. Water discount reduces water from a baseline ratio. Both affect how fast your soap traces, how long it takes to unmold, and the final bar hardness. Soaply defaults to showing water as a percentage of oils, which many soap makers find most intuitive. You can switch between methods in the calculator settings.
What does the INS value mean?
The INS value is a quality indicator for your soap recipe, calculated from the iodine and SAP values of your oil blend. An INS between 136 and 170 generally indicates a well-balanced bar with good hardness, lather, and conditioning properties. Values below 136 tend to produce softer, slower-curing bars. Values above 170 may indicate a bar that is very hard and potentially drying. It is a rough guideline, not an absolute rule.
Why do different calculators give slightly different lye amounts?
SAP (saponification) values can vary slightly between sources because natural oils are not chemically identical from batch to batch. Different calculators may use different reference values. Small differences of 1-2% are normal and safe. Soaply uses well-established average SAP values, and Pro users can customize SAP values for specific oil batches if they want maximum precision.
Oils and Recipe Design
What are the best oils for beginners?
A classic beginner recipe uses olive oil (for conditioning), coconut oil (for lather and hardness), and palm oil or shea butter (for hardness and creaminess). A simple starting formula: 40% olive oil, 30% coconut oil, 25% palm oil, 5% castor oil. This produces a balanced bar with good lather, hardness, and moisturizing properties. All of these oils are affordable and easy to find.
Can I substitute one oil for another in a recipe?
You can, but every oil has a different SAP value and different properties. Swapping oils changes the lye amount required and the bar characteristics (hardness, lather, conditioning). Always recalculate your recipe in a lye calculator after making substitutions. For example, replacing palm oil with cocoa butter changes the lye amount slightly and produces a harder bar. Soaply automatically recalculates everything when you adjust oils.
What is the maximum percentage of coconut oil I should use?
Coconut oil is excellent for lather and hardness but is highly cleansing. Most soap makers keep it at 15% to 30% for a balanced bar. Going above 30% can make the bar drying for people with sensitive or dry skin. However, 100% coconut oil soap (with a higher superfat of 15-20%) is popular for laundry bars and specialty soaps. The key is matching the coconut oil percentage and superfat to your intended use.
Using Soaply
Is Soaply free to use?
Yes, the core soap calculator is completely free with no account required. You can calculate lye, water, and view bar property predictions without signing up. Creating a free account lets you save up to 5 recipes, log batches, and access the community recipe library. Soaply Pro unlocks unlimited recipes, custom oils, recipe versioning, inventory tracking, the cost calculator, and priority support.
How do I save a recipe?
Create a free account or sign in, then click the 'Save Recipe' button below the calculator results. Give your recipe a name, add optional notes and tags, and save. Your recipes appear on the 'My Recipes' page where you can edit, duplicate, share, or delete them. Free accounts can save up to 5 recipes. Pro accounts have unlimited recipe storage.
What is the batch journal?
The batch journal lets you log every time you make a batch of soap. Record the date, any notes about the process (temperatures, trace time, additives), and track how the batch turns out. This is invaluable for refining your recipes over time and keeping consistent production records, especially if you sell soap.
What does Soaply Pro include?
Soaply Pro includes unlimited saved recipes, custom oil profiles with your own SAP values, recipe version history, ingredient inventory tracking, a cost calculator for pricing your soap, a shopping list generator, custom fragrance profiles, priority support, and early access to new features. Pro is $8 per month or $60 per year.
Can I share my recipes with other people?
Yes. Any saved recipe can be shared via a public link. The recipient can view the full recipe including oils, percentages, lye, water, and bar properties without needing an account. They can also import the recipe into their own account with one click. You control which recipes are shared and can revoke access at any time.
Troubleshooting
My soap is too soft after unmolding. What went wrong?
Soft soap is usually caused by too much water, not enough hard oils, or not enough cure time. Try using a higher lye concentration (less water), increasing coconut oil or palm oil percentages, or adding sodium lactate at 1 teaspoon per pound of oils. Make sure you wait at least 24 to 48 hours before unmolding, and give the bar a full 4 to 6 week cure.
What are dreaded orange spots (DOS)?
Dreaded orange spots are caused by rancid oils in your soap. They appear as small orange or brown spots and usually have an off smell. Common causes include using old or expired oils, high superfat with oils prone to rancidity (like canola or sunflower), storing soap in humid conditions, or not adding an antioxidant like rosemary oleoresin extract (ROE). To prevent DOS, use fresh oils, store cured soap in a cool dry place, and keep superfat at 5% or less for long-lasting bars.
Why did my soap volcano or overheat?
Soap volcanos happen when the batter overheats during saponification, usually in an insulated mold. Contributing factors include high sugar content (honey, milk, beer), high coconut oil percentage, fragrance oils that accelerate trace, and too much insulation. To prevent overheating, skip insulation for milk and sugar soaps, soap at lower temperatures (90-100F), use a water discount, and avoid fragrances known to accelerate.
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