Combining the Best Essential Oils for Soap Making

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If you make soap, you probably do it for one of two reasons. First, it allows artistic creativity while making something useful. And second, it allows control over all the ingredients.

Many soap makers begin the art because they want to eliminate chemicals, allergens, toxins, perfumes, and detergents from their households. They want a more natural product, but they also want it to smell good. And you don’t get much more natural than essential oils. Some people even learn  how to make essential oils at home.

But finding the best essential oils for soap making isn’t that easy. Each soap making technique throws different factors at you.

Before we get into choosing the right oils, I’ll first answer a question that almost every new soap maker asks: Can you use citrus juice, rose water, etc. to fragrance soap? Yes and no. Yes, you can use it for soap. But no, the fragrance won’t remain in the finished product. It’s not strong enough. Essential oils, and the less-natural fragrance oils, are highly concentrated and able to withstand the process.

The Best Essential Oils for Soap Making: Melt and Pour

Though melt and pour soap is by far not my favorite, and it’s certainly not natural, it has one huge advantage: It’s safe to craft around children. If your kids are old enough to understand certain precautions, such as using towels to handle hot dishes, they can create soaps as well.

A downside of using essential oils for melt and pour: some oils are not skin-safe and cause contact dermatitis. When diluted in soap, this usually isn’t a problem, but dropping undiluted EO on skin, and allowing it to stay there, can cause rashes, burns, and photosensitivity. Research which oils may cause skin reactions before using them for soap.

An upside of using EOs in melt and pour soap: because the soap isn’t alkaline and doesn’t require high temperatures, almost every fragrance will stick. It will last awhile.

Citrus and coconut fragrances are notorious for fading within goat milk soap recipes and other cold process soap because the pH of the soap reacts with these oils. But that’s not a worry with melt and pour.

For a refreshing and energizing melt and pour soap, try lemon, mixed with lemongrass and ginger. Or create a three-citrus combination of grapefruit, lemon, and orange, adding a cedarwood base note to bring the airiness down to earth.

Try pure lavender essential oil in melt and pour soap, without worry of fading. Or mix lavender and eucalyptus.

The Best Essential Oils for Soap Making: Cold Process

Here’s where things get tricky. Cold process soap making can kill a fresh fragrance, and the fragrance itself can complicate soap making.

Fruity and spicy oils can cause seizing, which is when the soap quickly thickens and solidifies just after you add the scent. Some herbals also cause the problem. Using oils which are solid at warmer temperatures, such as in coconut oil soap recipes, can intensify the problem. To avoid seizing, I do two things: First, I avoid the fragrances that can cause it, such as clove oil. But if I want that spicy smell, I will separate a little unscented soap batter and set it aside. Then, if the rest of the batter seizes after I add fragrance, I quickly glop it into molds then pour the liquidy, unscented batter around it to fill in any pockets or gaps. This creates a single, solid bar that can be cut after it completely solidifies and cools.

Perhaps the most tragic loss is that of a scent you had your hopes on. But there are some tricks to making fragrance last:

• Identify which scents won’t withstand the pH and heat. Citrus are the main culprits. If you truly want lemon soap, made with pure lemon essential oil, try melt and pour for the best results.
• Use alternatives, such as lemongrass or lemon verbena essential oils instead of lemon.
• Increase the amount of oil, using a fragrance calculator to identify how much to use. Some oils, such as 10x orange, are already more concentrated.
• Add kaolin clay to your soap recipe. This gives essential oil something to adhere to while creating a nicer lather and soothing skin.
• Anchor scents with deeper “base” notes. This means blending the lighter fragrances with something that has better retention, such as lavender with rosewood or grapefruit with ylang ylang.
• Store finished soap in a cool, dry environment that is away from direct sunlight. I like to stack it (with a little space between bars), with paper separating layers, in a cardboard box. Then I place the box in a bedroom closet, not a bathroom or kitchen cupboard.

If you want a relaxing, therapeutic fragrance combination, but want to extend the scent’s life in cold process soap, try mixing lavender oil with chamomile and patchouli or oakmoss.

For a refreshing, fruity-woodsy scent with excellent staying power, combine 10x orange oil, juniper, and Peru balsam.

Or make a therapeutic breathe-easy spa bar with eucalyptus, rosemary, and cedarwood.

Top, Middle, and Base Notes

When crafting fragrance combinations for either melt and pour or cold process soaps, you can improve the scent’s staying power by pairing top notes with an earthy base “anchor.” Top notes are the first fragrances noted by the nose, usually the light, citrusy, floral tones. The nose then identifies middle notes, which are a bit deeper, spicier, or woodsy. Base notes tend to be very earthy, such as patchouli, sandalwood, and myrrh. Pure orange oil may not “stick” long in cold process soap, but combining a 10x orange oil with patchouli and a little cardamom creates a spicy, citrusy combination, which will last a long time.

Existing recipes may call for “three parts lime EO, one part pine, two parts ginger.” This means, if you’re using a few drops, use three drops lime, one of drop pine, two drops ginger. Or three ounces lime, one ounce of pine, etc.

To create the best recipes, it can take trial and error to discover how much of each creates the scent you desire. Recipes are found online but you may want more of one oil and less of another. It’s ok to experiment as long as you avoid oils which cause unpleasant reactions and you use a fragrance calculator to determine how much to add to soap.

Using a Fragrance Calculator

Many soap making suppliers include fragrance calculators on their websites. Why use a fragrance calculator? For soap making with blended fragrance oils, the calculator helps determine how much oil to use, per pound of soap, if you want a light fragrance versus a deep, lasting scent. When using even the best essential oils for soap making, the calculator serves a second purpose: it indicates the maximum volume allowed safely. It takes into account the potential for phototoxicity or sensitizing skin, and gives you a maximum threshold, while allowing you to input all other factors and fragrance combinations.

Fragrance calculators also account for the fact that different essential oils have different fragrance strengths, so while a little myrrh oil easily fragrances soap, the same amount of neroli may not.

Of course, if you ask any longtime soap maker for their opinions on the best essential oils for soap making, you will get an assertive answer … that will differ between soap makers. Anyone selling essential oils may also give you different answers. But answering which EO is best for you is something only you can do.

What do you feel are the best essential oils for soap making? Do you have any scent combinations to share? We would love to hear about it.

Identifying Top, Middle, and Base Notes

(Some of these aren’t exclusive. For instance, lemongrass can be the middle note when combined with a top note of pure lemon essential oil.)

Ask the Expert

Do you have a soapmaking question? You’re not alone! Check here to see if your question has already been answered. And, if not, use our chat feature to contact our experts!

Hi, how many ml of essential oil per 500g of melt and pour soap? – Will

Essential oils, every single one of them, have a different recommended usage rate to be safe on the skin. In soap making, we measure essential oils either in ounces or in grams. To determine how much of a specific essential oil to use in 500 grams of melt and pour soap base, you will need to look up the Recommended Usage Rate of the essential oil in a melt and pour soap base. Reputable soap making companies provide this information readily on their sites, or you can look it up (simply Google “Safe Usage Rate” and the name of the essential oil) for each essential oil. To calculate the usage rate, take the recommended percentage for melt and pour and divide that amount by the amount of soap being used. For example, if you have a .5% usage rate for melt and pour, you would divide 500 grams of melt and pour by .5 grams of essential oil, which gives you 10.0 grams. These usage rates are approximate, so you can round up or down as necessary. – Melanie

Hi there! I just made an essential oil soap and I accidentally added too much essential oil to it (double the required quantity) will that be a problem? – Sara

Hello Sara, the answer is yes — this may very well be a problem. Every essential oil has a Safe Usage Rate to be followed, whether you are making soap or lotion or other bath and body products. The Safe Usage Rate is a very important set of guidelines that can protect you and those using your soaps from skin sensitivities, irritations, or even chemical burns from too much essential oil. To save this batch, I would recommend shredding down the soap and mixing with an equal amount of fresh, unscented soap batter to dilute the overall scent load. The shredded soap will also give a lovely confetti effect to the finished soap. In the future, Safe Usage Rate Calculators can be easily found online and will help you to keep your soaps safe, no matter which essential oils you are using. – Melanie