The Soap Base Breakdown: How to Choose the Right Oils for Your DIY Bar

So you want to make your own bar soap. You’ve got your mold, your lye, your gloves... but now you’re staring at five different oils wondering:

Which one do I actually need?

Welcome to the part of soap making where chemistry meets intuition — and yes, you’ve got this.

In this post, I’ll break down the most common soap base oils, what they do, and how to choose a combo that fits your goals — whether you’re going for moisturizing, cleansing, bubbly, or gentle.

And if formulas scare you? Don’t worry — the Apothery app builds it for you. More on that in a second.

First, What’s a Soap Base?

When you make cold process or hot process soap, you need two main things:

1. Oils or fats

2. Lye solution (water + sodium hydroxide)

The oils you choose determine how your soap will behave. That includes how hard it is, how well it lathers, how gentle it feels, and how long it lasts.

The Big Five (And What They Do)

Olive Oil

• Mild, moisturizing, and gentle

• Great for sensitive or dry skin

• Makes a soft, creamy latherUse it if: you want a nourishing bar or baby-safe soap.

Coconut Oil

• Cleansing, hard, bubbly

• Helps the bar harden quicklyUse it if: you want foam and cleaning power (great in shampoo bars).

Palm Oil (or sustainable alternatives like babassu)

• Hard, stable, makes a long-lasting barUse it if: you want a classic, firm bar that lasts.

Castor Oil

• Liquid oil that boosts bubblesUse it if: you want silky lather and smooth glide (used in small percentages).

Sunflower or Sweet Almond Oil

• Softening, rich in vitamin E Use it if: you want a gentler, skin-friendly feel.

Not Sure What to Combine?

If this feels like a puzzle, let the app help. Inside Apothery, you can generate a custom soap formula based on your skin type, preferences, or desired properties.

• Want a bar for oily skin? Select “deep cleansing” and we’ll adjust the coconut and castor levels.

• Want a gentle baby-safe bar? Choose “sensitive skin” and get a higher olive oil ratio.

• Want something luxurious? Add cocoa butter and the app will rebalance the rest.

You can even tell it what ingredients you already have — and it will build around those.

Less guesswork. More alchemy.

Example Beginner Formula

Here’s a well-balanced recipe to start with:

• 35% olive oil

• 30% coconut oil

• 20% sunflower oil

• 10% shea butter

• 5% castor oil

This gives you a creamy, firm, moisturizing bar with nice lather. But remember: your perfect bar depends on your skin, your climate, and your vibe.

Sage Advice (Literally)

Start small.Label everything. Let your bars cure fully.Use the app. It’s your lab assistant.Then tweak until it feels like yours.

Soap making isn’t about getting it right the first time. It’s about learning to speak in ingredients.

And Apothery?It’s your translator.

Catch you in the next DIY,Sage Ortega