A coconut-soy candle is not soy wax with coconut added. It is a different molecule stack, and the difference is what sets your fragrance load ceiling. We run a 70/30 coconut-to-soy split as our baseline for container blends, and every other spec on the sheet, pour temperature, wick size, cure time, bends to whatever load that split allows.
Push the load past the ceiling and the candle stops throwing. Pull it under and the shelf smells strong and the living room does not. Both failures look the same to a customer, and only a burn test tells them apart.
Why the coconut share changes what the wax can hold
Soy wax is a hydrogenated soybean oil. The full hydrogenation pushes the fatty acid tails toward stearic, which is why plain soy sits where it sits on a melt chart. The melt point across commercial blends runs from about 49 to 82 degrees C, and that range is not noise. It is the whole spec. A low-stearic pour gives you a wide, lazy pool that soaks the fragrance slowly and lets it evaporate in bursts. A high-stearic pour does the opposite and holds the load in place, but then it needs a hotter burn to release it.
Coconut wax sits lower on that stearic curve. The crystal matrix it forms is softer, which is exactly why a 70/30 split throws better than pure soy in our runs. The softer matrix takes more fragrance per gram before the load starts to reject, and the wider pool it produces spreads the burn evenly enough that the top note does not spike and fade. Density is a second spec you will feel in the math. Soy wax runs about 0.9 g per milliliter, and nine pounds of it will fill roughly ten 16-ounce jars. If you are quoting a jar price and your coconut share is off, your wax cost per unit is off by more than you think.
The load ceiling and the two failures that cross it
For a 70/30 coconut-soy split, we run our baseline fragrance load at 8 percent by weight, and we treat 10 percent as the hard ceiling. Past 10, two failures show up in the same batch. The first is frosting and surface separation, the fragrance crystals out on the top and the bottom and the wax in between carries less than the label says. The second is worse and quieter. The candle smells strong on the shelf, the load is in the wax, but on burn the pool is too small to drag the load up, and the throw at one meter drops to almost nothing.
That second failure is the one we have seen on the most complaints, because the customer does a sniff test on the shelf, buys the candle, and the first burn in the living room comes back weak. We have watched this fail when a load was raised to 12 percent to chase a stronger cold throw, and the hot throw fell off a cliff. If you are chasing a strong first burn, the fix is the pool width, not the load.
The burn test that catches what the shelf test misses
Our production test is three numbers, all read on the same candle, on the same day, in the same room. First, full pool width at 90 minutes. The melt line has to reach the glass wall, and if it does not, your pool is too small for the load you have in the wax. Second, throw at two meters, measured at the 30, 60, and 90 minute marks. We do not average. A candle that throws well at 30 and fades by 90 is a bad candle with a good first burn. Third, cold throw on a fresh, unburned jar, measured in the same room at the same temperature, because a cold throw that does not survive the first 90 minutes of burn is a load that was never in the wax at all.
Pour temperature is the variable that ties all three together. We pour a 70/30 split at about 76 degrees C and let the jar cool at room temperature for 48 hours before we cut the wick and ship. That window is narrow, and the numbers above only hold if the pour is inside it. If your cold throw is weak, your load is probably fine, and your pour temperature is the problem.
A 70/30 split is a working spec, not a starting point. Once you have a blend that passes the three numbers above, the only thing left to change is the wick, and the wick is where the last of the throw lives or dies.