Is Fragrance Load a Percent of the Wax or the Total?

The usual definition is a percent of the wax weight, not of the wax plus oil. NorthWood writes it as oil equals wax weight times fragrance load, and Glass Now takes fragrance as a percent of wax weight too. But shortcuts that start from a batch total or a jar's capacity quietly use the other method, and I have seen even a supplier's own examples slip between the two. The difference is small at low loads and adds up as the load rises.

What are the two methods?

Percent of the wax (the usual one). Oil = wax x load. For a total batch, wax = batch / (1 + load). NorthWood gives that same rearranged formula: exact wax weight equals total batch weight divided by one plus the fragrance load.

Percent of the total. Oil = batch x load, and wax is what is left. This is what you get if you multiply the batch weight by the load and call it done. It is also what you get from NorthWood's jar-fill method, which finds the space a jar holds, takes the load from that, and subtracts the oil from the wax.

Worked example: a 32 oz batch at 10 percent

Say you make 32 oz (907 g) of wax and oil together at a 10 percent load. All numbers are examples.

As a percent of the wax:

• Wax = 32 / 1.10 = 29.09 oz (825 g)
• Oil = 29.09 x 0.10 = 2.91 oz (83 g)
• Check: 29.09 + 2.91 = 32.00 oz

As a percent of the total:

• Oil = 32 x 0.10 = 3.20 oz (91 g)
• Wax = 32 - 3.20 = 28.80 oz (817 g)
• True percent of the wax: 3.20 / 28.80 = 11.1 percent

So the "10 percent" candle made the second way really carries 11.1 percent oil against its wax, 0.29 oz (8 g) more oil than the first way. If your wax tops out at 10 percent of the wax, you have gone over without knowing.

How big is the gap at other loads?

If you take the load from the total, the real percent of the wax is load / (1 - load):

Check one row: 0.08 / 0.92 = 0.0870, which is 8.7 percent.

Why does it matter?

Because a wax maker's maximum is usually written against the wax. NorthWood tells makers to check each wax brand's maximum load, and its guide lists soy at 6 to 10 percent of wax weight. Midwest Fragrance notes that too much oil can clog the wick, give a struggling flame and cause sweating. If your recipe card says "10 percent" and you worked it from the total, you may be at 11.1 percent against the wax. It also matters when two makers share a number: "8 percent" in two recipes can be different candles.

What if the supplier's numbers disagree?

They sometimes do. NorthWood's formula is based on wax weight, but its soy example for a 500 g batch at 8 percent shows 460 g of wax and 40 g of oil. That is 8 percent of the 500 g total, not of the wax. The same page's coconut and beeswax examples match the wax-based formula. I do not know why they differ. So when you copy numbers from a page, run the formula yourself, and weigh the result against the wax's own sheet.

Common mistakes

• Taking the load from the batch total, and calling it a percent of the wax.
• Comparing your load to a supplier's maximum without checking what they mean.
• Changing methods between the test candle and the production batch.
• Not writing the method on the recipe card.
• Weighing oil and wax by volume.
• Forgetting that a jar-fill shortcut may use the total.

Questions

Which method should I use?

The percent of the wax. It matches how supplier guides and most tech sheets talk about maximums, which makes your numbers comparable. Whichever you choose, write it on the recipe.

What if my wax sheet does not say?

Ask the supplier. Their sheet is the final word on what its number means.

Does it matter for a small candle?

Less. On a candle that holds 6 oz (170 g) of wax and oil together, at 8 percent the gap is about 0.04 oz (1 g). At 12 percent it is 0.72 - 0.64 = 0.08 oz per candle, which is about 1.85 oz (52 g) over 24 candles. It matters most when you are near the wax's limit.