How to Blend Essential Oils: Notes and a Ratio to Calculate

Top, middle and base notes are a convention, not a measurement, and a blend that follows the pyramid can still be unusable if one oil in it has a lower ceiling than the rest. The method that works at the bench is simpler: fix the dose you want, look up the highest allowed percentage for each oil, and let the most restricted oil set the ratio. With sage that oil is nearly always the sage, because its thujone sets a ceiling far below what the other oils in a blend allow.

Sage Essential Oil bottle

Sage Essential Oil

Our own Sage Essential Oil, in sizes from 0.5 oz to bulk.

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What the "notes" label actually rests on

A granted US patent on fragrance compositions (US 10,501,706 B2, 2019) states the situation bluntly: perfumers classify materials as base, heart or top "according to their specific characters," and "there is no universal convention because this type of classification scheme tends to be subjective." That patent itself sorts materials by vapor pressure, with a threshold of 0.001 Torr at 25 C. Volatility is the idea behind the pyramid, so here are boiling points for five constituents that matter in sage oil, as recorded in PubChem:

ConstituentBoiling point recordedPubChem sources
Limonene175 to 178 CHSDB, CAMEO, OSHA
1,8-Cineole176 to 177 CHSDB, JECFA
Linalool194 to 200 CHSDB, ICSC, JECFA
Thujone (isomers not separated)200 to 201 Cone vendor database entry
Camphor204 to 209 C (one source says it sublimes)ICSC, Merck Index via HSDB

Two things follow, and the second is reasoning from the table, not a finding. First, the whole list sits inside about 30 degrees; boiling point is a rough proxy for evaporation, and vapor pressure is the better figure. Second, a single oil straddles the pyramid. Sage oil carries a cineole component at the volatile end and camphor and thujone at the heavy end, so labelling it "a middle note" is a judgement about the overall smell. The shop's own pages make the same point without saying it: one of our two listings is described as a middle note and the other as top to middle.

The limiting-ingredient method

For any blend, the largest share an oil can have in the concentrate is its cap divided by your total dose. Total dose is the percentage of all oils together in the finished product. The ratio you can calculate is therefore:

maximum share of oil X in the concentrate = cap of X divided by dose.

Where the caps come from matters. Here are three we can source:

Lavender, cedarwood, frankincense and pine have no cap in this article because we did not fetch one; check your supplier's documentation for each before you count them as unrestricted.

A worked formula, by weight, not tested by us

We have not made this blend or smelled it; it is arithmetic. Suppose you want a 20 g concentrate for a body product, and you want the sage to be 20% of it. Choose the dose first. The sage cap of 0.17% divided by a sage share of 0.20 gives a maximum total dose of 0.85%. Bergamot at a 20% share gives 0.40 divided by 0.20 = 2.0%, which does not bind. The sage binds.

OilShare of concentrateIn 20 gCeiling on total dose (cap / share)
Sage20%4.0 g0.17 / 0.20 = 0.85%
Bergamot, expressed20%4.0 g0.40 / 0.20 = 2.0%
Lavender40%8.0 gno cap fetched
Cedarwood20%4.0 gno cap fetched

Those are the shop's own listed pairings for sage (lavender, bergamot, cedarwood). Now convert to a batch. At the 0.85% ceiling, 30 mL (about one ounce) of carrier takes 0.255 mL of concentrate, which is about 5 drops at roughly 20 drops per mL. Twenty percent of 5 drops is 1 drop of sage, which is the same 0.17% we started from, and the bergamot comes out at 1 drop, 0.17%, well under 0.40%. Drops vary by dropper, so weigh if you can: using the COA batch's measured density of 0.915, one drop of sage (0.05 mL) is about 0.046 g.

The loop closes the other way too. If a recipe asks for 3 drops of bergamot in an ounce, that is 0.51% against a 0.40% cap, and the arithmetic says to stop before the nose does.

Check the other oils for thujone

The IFRA thujone standard says natural thujone contributions are counted by summing the isomers and refers to contributions from other sources. Medsafe, New Zealand's medicines regulator, lists thuja (Thuja occidentalis), sage and wormwood among oils associated with seizures, naming camphor, thujone and cineole. So read the Latin name on every partner oil. If a bottle sold as "cedar" is cedar leaf from Thuja occidentalis, it adds thujone to a blend that already has a thujone problem, and a blend of two such oils has a lower ceiling than either. Our process page says to leave sage alone with a seizure disorder and to avoid it in pregnancy, breastfeeding and around children; a blend does not change that.

For a diffuser the cap is different

None of the caps above apply to air; no authority we fetched sets one. The principle that does carry over is the share: keep the sage at the smaller fraction of a diffuser blend, use a lighter hand than you would with a mint or a citrus, which is our process page's wording, and read what air studies measured and the drops arithmetic before settling a count.

How to judge a blend before you commit

  1. Blend a few drops, not a batch. Smell it at once, after ten minutes and after an hour on a paper strip, and write down what changed. The pyramid predicts only the order, not whether you like it.
  2. If you intend to put it on skin, apply the carrier-diluted blend as the American Academy of Dermatology describes for new products: a quarter-sized spot on the inner arm, twice daily for seven to ten days; stop and wash it off if there is redness, itching or swelling.
  3. Write the formula in weights and percentages, not drops, so it can be scaled.

For ready-made pairings see the ten sage blends and, for a skin-ready batch size, the roller blend arithmetic. The safety side is in the thujone article.

We sell two sage oils and no other oils, carriers or bottles, so every partner material above comes from a supply shop; our COA gives density, refractive index and optical rotation for one batch and no constituent data, which is why every figure here is labelled as general or as arithmetic.

Sage Essential Oil bottle

Sage Essential Oil

Sage Essential Oil from our own shop, in sizes from 0.5 oz to bulk.

From $13.99

Shop Now →

Sources & Further Reading