Adding fragrance, and at what temperature

The step that decides whether the candle smells of anything, and it is a temperature and a stir.

The temperature comes from the wax

The wax supplier publishes a fragrance addition temperature, typically well above the pour temperature.

Use it. It is the temperature at which the wax's structure will accept and hold the oil, and it is not the same as the pour temperature or the melt temperature.

Check it against the oil's flash point on the safety data sheet. For most candle fragrance oils the flash point sits comfortably above soy addition temperatures, but the check costs nothing and it is the one place these two numbers meet.

Stir properly

Two full minutes, gently, reaching the bottom and the sides.

This is the step people rush, and under-stirring is a real cause of sweating and of candles from one batch throwing differently from each other.

Gently, because beating air in gives you bubbles against the glass and a larger surface for oxidation.

Why too hot and too cool both fail

Too hot: the lighter notes flash off into the room. The workshop smells wonderful and the candle does not.

Too cool: the wax has begun to set and the oil never fully binds. It shows later as sweating or as candles that smell uneven.

Both produce the same complaint, weak throw, from opposite causes, which is why a thermometer is worth more here than experience.

Then let it fall

From addition temperature down to the pour range, stirring occasionally so it cools evenly.

Do not accelerate it in cold water: uneven cooling in the pot sets up uneven crystallization in the jar.

And do not hold it warm for an hour while you do something else. Time at temperature is scent leaving.

References