Candle Fragrance Load: Percent, Limits and Curing
How fragrance load percent works, why 6 to 10 percent is typical, the maximum a wax can hold, and how curing affects cold and hot throw.
What fragrance load actually means
Fragrance load is the weight of oil you add expressed as a percentage of the wax weight, not of the finished candle. If you melt 200 grams of wax at a 10 percent load, you weigh in 20 grams of oil, giving 220 grams of scented wax. Because it is a ratio, the same percentage scales cleanly from a single tester up to a full production pour. Working by weight rather than by drops or fluid ounces is what keeps a recipe repeatable from batch to batch.
Why 6 to 10 percent is the usual range
Below about 6 percent many candles smell faint once lit, especially in a large room. Between 6 and 10 percent most soy and paraffin blends carry a clear scent without trouble, which is why 8 percent is such a common default. Push past the wax maximum and the excess oil has nowhere to bind, so it can bead on the surface, cloud the wax or pool at the bottom. More oil does not always mean more scent, because a wick and wax can only vaporise so much fragrance per hour.
Finding your wax maximum
Every wax has a maximum load on its technical data sheet, often near 10 to 12 percent for common containers waxes. That figure is the ceiling the wax can absorb and still burn cleanly, not a target to hit. Natural waxes like soy tend to hold less oil than paraffin, and blends fall in between. Start a percent or two under the maximum, then adjust based on how the tester burns rather than assuming the highest number is best.
How curing changes the throw
Cold throw is the scent from an unlit candle and hot throw is the scent when it burns. Both usually improve with curing, the resting period after pouring while the oil and wax bind. Many soy candles are given one to two weeks to cure before testing, and paraffin often needs less. If a fresh candle seems weak, cure it fully and retest before you decide to raise the load, because a longer cure can lift the throw without any extra oil.