How to Choose the Right Oils for Your Soap
Picking oils is where new soapmakers get lost. They don't know the right balance of what to put into their soap, so they go looking for tried-and-true recipes. But here's the thing: unless you learn the fundamentals of choosing oils, you'll always be hunting for somebody else's recipe. So here's where I show you what oils do, and how to balance them in your own.
Every oil has its job
Choosing the right oil means knowing what it does and how it performs in a bar. You're looking for four things: hardness, lather, cleansing, and conditioning. Always remember — the oils work together as a team. No single oil does all four jobs well.
Fatty acids are the job description
Every oil has a fatty acid profile, and the fatty acids decide the job that oil does in your soap. Olive oil is high in oleic acid, which is very mild on skin, so it won't strip you when you wash. Coconut oil is high in lauric acid, which means serious cleansing power — it gets the cleaning done, but it won't be as gentle.
Here's the quick key:
• Lauric + myristic = cleansing and big bubbles
• Palmitic + stearic = hardness and creamy, stable lather
• Oleic = conditioning and mild
• Linoleic = conditioning and silky, but too much makes a soft bar that can go rancid
• Ricinoleic = lather magic (only castor oil has it)
Let the soap calculator keep you honest
Soapmakers build recipes in percentages and run them through a soap calculator. It does two jobs. First, it tells you exactly how much lye you need — every oil needs a different amount, and that part is safety, not guesswork. Second, it scores your recipe: hardness, cleansing, conditioning, bubbly, creamy — each one with a suggested range. Drift too far outside a range and the numbers warn you before your bar does. Too much cleansing? Drying bar. Too little hardness? A soft bar that melts away in the dish. The calculator gives you guidelines for balancing it all. Not gospel — guardrails.
Know your supplier
Before we get to the list, this matters. Not every supplier is the same. They all have their standards and values, and finding one that aligns with yours is important. Some suppliers buy cheap so they can sell in bulk, and that can become your problem — oil that's already rancid can ruin a whole batch. And in my case, buying from a supplier that does animal testing wouldn't align with my values as a cruelty-free maker, because whatever you're trying to accomplish in your future will come back to how you practiced right now. Choose wisely.
The oils
Hard oils, liquid oils, fats and butters, plant oils and animal fats — they're all the same in one way: they all have a fatty acid profile, and they all do a job inside soap. Here's the list.
HARD OILS (the cleansers)
• Coconut oil — Lauric ~48%, Myristic ~19%, Palmitic ~9%, Oleic ~6%. Hard bar, huge bubbles, deep clean. Over 30% and it can dry skin out.
• Palm kernel oil — Lauric ~48%, Myristic ~16%, Oleic ~15%, Palmitic ~8%. Hard, bubbly, cleansing, like coconut.
• Babassu oil — Lauric ~50%, Myristic ~20%, Oleic ~10%. Coconut's gentler cousin — same punch, less drying feel.
ANIMAL FATS (structure)
• Tallow — Oleic ~43%, Palmitic ~26%, Stearic ~20%. Rock-hard bar, creamy stable lather.
• Lard — Oleic ~44%, Palmitic ~26%, Stearic ~13%, Linoleic ~10%. Hard, white, mild. Criminally underrated.
PALM
• Palm oil — Palmitic ~44%, Oleic ~39%, Linoleic ~11%, Stearic ~5%. Hardness and creamy lather in one oil.
BUTTERS (hardness + luxury)
• Cocoa butter — Stearic ~34%, Oleic ~35%, Palmitic ~26%. Hard, conditioning, helps bars last.
• Shea butter — Stearic ~42%, Oleic ~45%, Linoleic ~6%. Creamy and skin-loving.
• Mango butter — Stearic ~39%, Oleic ~43%, Palmitic ~8%. Like shea, but lighter.
• Kokum butter — Stearic ~53%, Oleic ~36%. The hardest butter. Structure without greasiness.
LIQUID OILS (the conditioning base)
• Olive oil — Oleic ~73%, Palmitic ~11%, Linoleic ~10%. Mild and gentle, the sensitive-skin star. Softer bar, longer cure.
• Castor oil — Ricinoleic ~90%. Nothing else has this. At 5–10% it turns thin lather into rich, stable, lotion-like bubbles.
• Sweet almond oil — Oleic ~65%, Linoleic ~25%. Light, conditioning, lovely slip.
• Avocado oil — Oleic ~67%, Palmitic ~16%, Linoleic ~12%. Rich and nourishing.
• Apricot kernel oil — Oleic ~65%, Linoleic ~28%. Light and quick to absorb.
• Rice bran oil — Oleic ~42%, Linoleic ~33%, Palmitic ~20%. Olive's budget rival — silky and gentle.
• Canola oil — Oleic ~62%, Linoleic ~20%, Linolenic ~10%. Cheap and mild, but watch its shelf life.
HIGH-LINOLEIC OILS (use with respect)
• Sunflower oil (regular) — Linoleic ~66%, Oleic ~20%. Conditioning, but too much means a soft bar and orange rancidity spots.
• Sunflower oil (high oleic) — Oleic ~82%, Linoleic ~10%. The fix for the one above. Similar price, far better behaviour.
• Soybean oil — Linoleic ~51%, Oleic ~23%, Linolenic ~7%. Budget filler. Keep the percentage modest.
• Grapeseed oil — Linoleic ~70%, Oleic ~16%. Silky and light, with the shortest shelf life of the bunch.
• Hemp seed oil — Linoleic ~55%, Linolenic ~20%. Beautiful stuff, but in soap use small amounts only. It goes rancid fast.
THE ODD ONES
• Jojoba — not a true oil; it's a liquid wax (~70% eicosenoic acid). Barely saponifies. A little adds luxury, a lot is wasted money.
• Fractionated coconut oil — ~100% caprylic/capric. Doesn't harden or lather like regular coconut oil. Mostly a leave-on ingredient.
Rules of thumb
Balance hard oils to liquid oils — around 60/40 is a classic starting point. Cap the coconut. Respect the castor. Then make the recipe yours.
The only way to learn
Honestly? The numbers only take you so far. The only way to really learn is to try. Make a batch. Make mistakes. Try again, and again, until you land on the recipe that pleases you — the one you're proud of, the one you can share with family and friends and watch them love it too. That's the whole game behind making soap.
And if you want to learn it hands-on, this is exactly where we start in my workshops.
One last note: these are typical values. Real profiles shift by supplier, harvest, and batch — which is, again, why knowing your supplier matters.