How to Blend Fragrance Oils for Candles

A blend does not change your fragrance load. If your wax takes an 8 percent load, the total oil in the candle is 8 percent of the wax, and the blend decides how that oil is split between your oils. So work out the total oil first, then divide it. Candlewic suggests starting at 1 to 1 for two oils and adjusting for how strong each one is, and testing blends in small batches before you scale up.

What are the steps?

1. Check each oil. Note its flash point and its usage limit on the product page or safety data sheet (see our flash point guide). Your wax's maximum load still applies to the total oil.
2. Sniff first. Candles and Supplies starts with one drop of each oil on a blotter, adds one drop at a time to whichever oil needs more, and records every drop so you can repeat it.
3. Turn the drops into parts. Say 5 parts of oil A, 3 of B, 2 of C. That is 10 parts.
4. Turn parts into percents of the oil. 5 / 10 = 50 percent, 3 / 10 = 30 percent, 2 / 10 = 20 percent.
5. Make a small test blend by weight. Candlewic says to test in small batches before scaling. Weigh each oil in grams on your scale into one cup.
6. Pour a test candle, cure it, burn it. Judge cold and hot throw separately after the cure (see our guide on the difference), and write the blend on the recipe card.

What is a top, middle and base note?

Candles and Supplies groups oils by how fast they evaporate. Top notes are light and fresh, the part you smell first. Middle notes are the body. Base notes are deep, warm and last longest. Its suggested shares are about 5 to 20 percent top, 50 to 80 percent middle and 5 to 20 percent base. Treat that as one supplier's starting guess for any blend, not a candle test result. It also notes that some oils can sit in more than one group, such as lavender (top or middle).

Worked example: a 25 oz batch

Say you pour 25 oz (709 g) of wax at an 8 percent load of the wax, split 50/30/20 across three oils. All numbers are examples.

• Total oil: 25 x 0.08 = 2.00 oz (56.7 g)
• Oil A at 50 percent: 2.00 x 0.50 = 1.00 oz (28.35 g)
• Oil B at 30 percent: 2.00 x 0.30 = 0.60 oz (17.01 g)
• Oil C at 20 percent: 2.00 x 0.20 = 0.40 oz (11.34 g)
• Check: 1.00 + 0.60 + 0.40 = 2.00 oz, and 28.35 + 17.01 + 11.34 = 56.70 g

For a small test, take 100 g of wax at 8 percent. That is 100 x 0.08 = 8 g of oil. At the same split it is 4.0 g, 2.4 g and 1.6 g (check: 8.0 g). For two oils started at 1 to 1, it is 4 g and 4 g. If A is too loud, try 3 to 1, which is 6 g and 2 g.

Weigh in grams even for the sniff test where you can. Drops are not weights, because oils differ in thickness and drop size. That is my own practice, not a source's claim. Our guide on weighing covers why.

Does the blend change the fragrance load?

No, the total is what counts. A common slip is putting 8 percent of each oil in, which for three oils is 24 percent and far past any wax's limit. Candlewic notes each wax has a maximum load, and going over can cause poor burning or fragrance seeping out. For the oils' own limits, my cautious rule is to use the lowest usage limit among them. I could not find a source on how to combine IFRA limits across a blend, so ask your oil supplier for blends.

What about flash point in a blend?

I did not find a source for a blend's flash point. My cautious working rule is the lowest flash point among the oils until I ask the supplier. It is a rough guide, not a measured number. CandleScience says low flash point oils do not burn off when added to wax and poured promptly, and Craftybase says to check the data sheet before using any new oil.

Common mistakes

• Putting the full load in for each oil.
• Blending by drops and never writing down the amounts.
• Scaling to a big batch before one test candle has cured and burned.
• Changing the blend and the wick at the same time.
• Judging a blend by smelling the bottle, since the scent in wax and in flame can be different.

Questions

How many oils are too many?

I could not find a rule from a source. Most sample blends on the Candles and Supplies page use two or three oils, and a few use more. Start with two, then add a third once you know what each does.

Should I blend oils before I add them to the wax?

Candles and Supplies blends in a bottle and then tests the blend in the product. I weigh the oils into one cup and add that to the wax at the wax's add temperature, so everything is stirred in once. That is my habit, not a source's rule.

Can I use the same blend in a different wax?

Maybe, but test it. Craftybase says different oils behave differently at the same percent, and waxes hold different maximums.