There are no hard rules
Experienced candle makers often say fragrance blending has few firm rules. One supplier primer puts it bluntly: apart from the idea of fragrance notes, there are no hard principles, and you can combine fragrances in whatever ratios you like. That freedom is useful, but a few habits make it far less frustrating.
Understand top, middle and base notes
Fragrances are commonly grouped by how fast they evaporate:
- Top notes: the first impression. Light and quick to fade, such as citrus, herbs and bright fruits.
- Middle (heart) notes: the main character of the blend, such as florals, spices or green notes.
- Base notes: heavier and longer lasting, such as vanilla, musk, wood or amber. They give depth and help the scent last.
Placement is not fixed: a scent that acts as a base note in one blend may act as a middle note in another, and sources disagree about where particular ingredients belong. Treat any chart as a rough guide. The same note structure applies when scenting soap; see soap scent recipes and combinations.
Test before you pour
You do not need to waste wax to see whether two scents work together.
- Dip a separate Q-tip or blotter strip in each oil.
- Put them together in a sealed jar or bag.
- Wait anywhere from about an hour to a day, then smell.
- If one oil dominates, add an extra strip of the lighter one to shift the balance.
- Write down the ratio you landed on.
If you are brand new, begin with a simple 50/50 blend, or use a recipe published by a supplier and adjust it.
Blend ratios and the 30/50/20 starting point
A common beginner suggestion is to use three oils, one per note layer, in roughly 30% top, 50% middle and 20% base. It is a starting suggestion rather than a rule, and some guides divide the layers differently. Following it will not guarantee a great candle, but it gives you something to adjust from. After mixing a blend, some makers let it rest for 24 to 48 hours before judging it.
You may also come across an “84 rule” for candles. There is no reliable, widely agreed definition for it, so it is best not to rely on it.
Scents that tend to pair well
Vanilla, lavender and sandalwood are often described as easy to pair with brighter florals or citrus. Some simple ideas to test, not guarantees:
- Lavender with a woody base
- Citrus top with a vanilla base
- Floral heart with a soft musk base
Remember that pre-blended fragrance oils can be combined too, which produces a new note profile. For what suppliers’ customers buy most, see our guide to the most popular fragrance oils.
Calculating and measuring a blend
- Decide your total fragrance load. Many suppliers suggest roughly 6% to 10% for fragrance oils, but check your wax. See the essential oil candle ratio guide.
- Multiply wax weight by the load to get total fragrance weight. For example, 10% of 5 oz of wax is 0.5 oz.
- Split that weight using your tested ratio. A 50/50 blend would use 0.25 oz of each.
- Weigh every oil. Do not use drops.
Adding to wax and testing the candle
Add the blend to melted wax at the temperature your wax supplier recommends (commonly cited at around 180 degrees F or 82 degrees C), stir gently for about two minutes, pour, and cure. Suppliers suggest anywhere from about a week to two weeks before burn testing. See when to add essential oil to soy wax for timing details.
Which fragrance should I use, and what holds scent longest?
Choose oils sold for candles and test them in your wax. In general, base notes such as woods, musks, amber and vanilla tend to last longest, while bright citrus fades fastest. For essential oils, see our list of the strongest essential oils for candles, and for staying power, read how to make essential oil fragrance last longer.
Selling your blends
If you sell candles with a custom blend, you cannot simply reuse the labels of the original oils. You may need updated safety data and compliant labelling for the new blend, and you should check with your insurer. Rules depend on where you live.
For the full process of creating your own scents, see our DIY fragrance oil for candles guide.