When fall arrives, the world fills up with cinnamon and clove. That’s what pumpkin spice is made of, after all. So why don’t we make a pumpkin spice soap for the season?
We love seasonal things, and we love pumpkin spice in our pie. On your skin, though, it’s a different story. Let’s talk about essential oils (EOs) and how they are, and aren’t, “safe.” Not all EOs are equal. Lavender and sweet orange are gentle when used within sensible limits. Cinnamon is a different matter.
We’re talking here about the “kitchen spice” EOs: cinnamon, clove, oregano and thyme. If you take one thing away from this post, let it be this little rhyme:
Kitchen spice don’t play nice.
But aren’t EOs natural? They’re not chemical fragrances, right? Yes… and no. Let’s look at what makes fragrances suspect, how EOs differ, and how we can use them safely.
The Trouble with Fragrance
Many people are wary of fragrances, and understandably so. That one word on a label can stand for a mixture of many compounds without naming any of them. Some fragrance mixtures contain phthalates, used as solvents and fixatives. The word “fragrance” alone won’t tell you whether they’re there.
Picture this: to smell something, molecules have to leave their source and travel through the air into your nose. That’s volatility. Because these compounds are flighty, making a scent last is a challenge, and whole technologies exist to keep fragrance around longer.
One uses tiny capsules of fragrance that settle onto fabric in the wash. Friction breaks them open later, which is how a shirt can still smell like “fresh laundry” long after washing. You may not have wanted to have those microspheres imbedded against your skin, but that's how laundry scent can work!
Little wonder people reach for essential oils instead. But are essential oils safe?
To answer that, we have to think about chemistry.
What's in a Bottle of Fir?
Take the grand fir essential oil we distill from our own trees, for example. I’ve mentioned how miserable the yield is: a whole F-150 long bed full of twigs gives us a pint, a quart at best.
These oils are a marvel. With dozens upon dozens of compounds, they don’t just smell “like a fir tree.” They’re nuanced, floral, resinous, all of it. When I first smelled our grand fir oil, I expected something like Pine-Sol. I was stunned by how complex and layered it was.
Many of those compounds help the tree defend itself against pests and disease, and distillation concentrates them. They’re potent. They’re also not a different kind of chemical from what you find in fragrance. Limonene, for example, is in our grand fir oil, in orange peel, and in countless fragrances. Ours is made by a tree; in a fragrance it may be isolated or produced industrially. But when the molecule is identical, it behaves identically. Limonene can oxidize on exposure to air and become a skin sensitizer, no matter where it came from.
Natural origin doesn’t make a compound harmless.
That’s why we’re careful with dosage and stay well within safe-use guidelines. It may also be why people sometimes say natural cold process soaps “don’t smell as strong.”
Dilution Is Only The Beginning
Some EO constituents are sensitizers on their own; others become more sensitizing as they oxidize. This is one reason we don’t recommend putting undiluted essential oils on your skin. But “dilute it” is only the start. How much? Which oil? Where on your body, and how often?
A homemade scented roll-on deserves more thought than a generic number of drops in almond oil.
The International Fragrance Association (IFRA) publishes standards setting maximum concentrations for certain fragrance materials in different kinds of products. Soap rinses off. Balm stays on. Lip balm has its own category and limits can differ a lot. (We give examples further down!).
Many restrictions apply to individual compounds within essential oils. That matters because plants don’t follow a fixed recipe: composition varies with growing conditions, harvest, and distillation. So we buy from reputable suppliers who provide batch-specific composition data, usually a GC/MS report (gas chromatography–mass spectrometry). Then comes the math, plus checking the applicable safety information and restrictions.
Blending makes the math more interesting. We combine base, middle, and top notes to tell a little scent story, but the same restricted compound can show up in several oils, and every contribution has to be added up.
Which Finally Brings Us to Pumpkin Spice
Cinnamon bark oil contains cinnamaldehyde. Clove oil is rich in eugenol. Both have very tight IFRA restrictions.
(Warning: Bunch of numbers below - but it is important to understand this!)
For cinnamaldehyde, the maximum in finished rinse-off soap is 0.49%. In hand and body products that stay on the skin, it’s just 0.064%. In lip products, 0.045%. We are talking about less than a drop here in a 100g batch (3.5 ounce)!
Those are percentages of cinnamaldehyde, not of cinnamon oil.
For illustration: if a cinnamon bark oil is 75% cinnamaldehyde, that leave-on limit works out to about 0.085% cinnamon oil. In a 100-gram batch of balm, that’s roughly 0.085 gram. Barely a smidgen, and certainly not something to measure with a "glugg" from a bottle or a drop from a pipette.
Eugenol’s limits are higher: 4.9% in soap and 0.64% in leave-on hand and body products. So cinnamon and clove aren’t interchangeable, and neither is automatically off-limits. They just need careful formulation, and a finished blend still has to be checked for its other restricted constituents.
Could we formulate a pumpkin spice soap within the limits? Yes. We’ve simply chosen to take our seasonal fun in another direction.
This year we made a special holiday milk stout soap with a warm blend of frankincense, vetiver, and pine. Those oils get the same careful attention to composition and concentration. And we think it's a marvelous soap! It will be ready for purchase in November. So let's agree : the pumpkin spice can stay in the pie.
And the ditty to remember on EO's? Kitchen Spice don't play nice!