Ever picked up a bar of handmade soap and noticed how soft and moisturizing it felt? That magical feeling isn’t just about using natural ingredients—it’s often the result of superfatting. It’s a term that might sound technical at first, but once you understand it, you’ll wonder how anyone makes soap without it!
Superfatting is a technique used by soap makers to ensure their soap is gentler, more nourishing, and kinder to the skin. It’s a crucial concept, especially for anyone making cold or hot process soap at home. In this guide, we’ll dive deep into what superfatting means, why it’s important, how to calculate it, and how it can transform your soap from basic to luxurious.
What Does Superfatting Mean in Soap Making?
Superfatting refers to the process of adding extra oils or fats to a soap recipe beyond what is needed to fully react with the lye (sodium hydroxide) during saponification. In other words, it’s the portion of oils that remain unsaponified—they don’t turn into soap but instead stay in the final bar as free oils. This creates a more moisturizing and skin-loving product.
People often confuse superfatting with “lye discounting,” but while the two are closely related, they aren’t exactly the same. A lye discount simply means using less lye than is required for full saponification, while superfatting can also involve intentionally adding oils after the soap has begun thickening (called “trace”) to ensure they don’t fully react with the lye.
Why Superfatting Matters for Skin Care
The biggest benefit of superfatting is its ability to make soap more moisturizing. When extra oils are left in the bar, they help form a protective layer on the skin, sealing in moisture and preventing dryness. This is especially important for people with sensitive skin, dry skin conditions, or anyone looking for a gentler cleansing experience.
Different oils bring different benefits. For example, shea butter is rich and soothing, avocado oil is packed with vitamins, and olive oil provides a silky smooth feel. By choosing the right oils for superfatting, you can customize your soap to meet the needs of different skin types—whether it’s a baby’s delicate skin or tough, calloused hands.
How to Calculate Superfat in Soap Recipes
Superfatting is typically expressed as a percentage. A 5% superfat means that 5% of the oils in your recipe will remain unsaponified. Most soap makers stick to a range between 5% and 8%. Going below 5% can make soap harsh, while going above 8% may lead to a greasy bar or even spoilage over time.
To calculate your superfat, you can use online soap calculators like SoapCalc.net or Bramble Berry’s lye calculator. These tools allow you to enter your recipe, choose your superfat level, and get precise measurements for how much lye to use. Always double-check your measurements and make sure you’re working with accurate lye purity to avoid any unpleasant surprises!
Superfatting Methods: Before vs After Trace
There are two main methods of superfatting: adding extra oils during the recipe formulation (before trace) and adding them later, after trace or during the cooking phase (for hot process soap). Both methods work, but they produce slightly different results.
When you superfat before trace, the extra oils are mixed evenly throughout the batter. This is easier and more common among beginners. However, some of those oils may still react with lye, depending on how long the soap is emulsified before pouring.
In contrast, adding oils after trace or during the cook (in hot process soap) ensures those oils are more likely to remain free and unreacted. This can give your soap an even richer, creamier feel. The downside? It’s harder to evenly distribute the oils, and there’s a slightly higher chance of spoilage if you’re not careful.
Common Superfatting Mistakes to Avoid
Superfatting is a powerful technique, but it’s easy to go overboard. One of the most common mistakes is adding too much superfat, which can lead to soft, greasy soap that doesn’t harden properly. Excess oil in a soap bar can also become rancid over time, leading to dreaded orange spots (DOS), which not only look unappealing but can ruin the entire batch.
Another frequent issue is incorrect measuring. Always use a digital scale and ensure you’re calculating your lye and oils precisely. Lye purity varies, so using a calculator and double-checking your numbers can prevent skin irritation or soap failure. It’s always a good idea to start small when testing new superfatting levels—experiment with mini batches and make tweaks before committing to larger recipes.
Best Oils to Use for Superfatting
Not all oils are created equal when it comes to superfatting. Some oils, like olive oil, shea butter, sweet almond oil, and jojoba oil, are beloved for their skin-nourishing properties. They add a luxurious feel to soap and offer benefits like deep moisturization, anti-inflammatory properties, and improved skin texture.
Castor oil is also a favorite because it helps with lather, though it should be used in moderation. Avocado oil is rich in vitamins A, D, and E, making it perfect for dry or mature skin. On the flip side, oils like palm or coconut can be drying in high amounts, so they’re best balanced with more conditioning oils.
It’s also wise to consider shelf life. Oils like flaxseed or hempseed can go rancid quickly, so if you’re planning to store your soap for a long time or sell it, stick with more stable oils.
Conclusion
Superfatting is one of the most essential techniques in soap making—and now, it’s no longer a mystery! By understanding what superfatting is, how it works, and how to apply it effectively, you can create bars that are not only cleansing but also deeply nourishing. Whether you’re crafting soap for yourself, your family, or your customers, mastering superfatting will take your soap game to the next level.
So go ahead—grab your oils, run those numbers through your favorite soap calculator, and start experimenting! Your skin (and everyone else’s) will thank you.