No cold throw, or no hot throw

Scent is what most customers buy a candle for, and the two ways it fails have different causes and different fixes.

Two different failures

Cold throw is the smell of the unlit candle: what sells it in a shop.

Hot throw is the smell when it burns: what decides whether they buy another.

A candle can have one without the other, and which one is missing tells you where the problem is.

Cold throw

Weak cold throw usually means not enough fragrance, or an oil that is simply quiet when cold. Some notes, particularly the heavier woods and musks, barely register unlit.

It also means the candle has not cured. A soy candle typically needs one to two weeks for the fragrance to bind fully through the wax, and a candle judged the day after pouring will disappoint on both throws.

Judging a candle too early is a common reason a maker adds more oil than they needed.

Hot throw

Strong cold throw and weak hot throw is the more interesting failure, and the answer is nearly always the melt pool.

Throw comes from the surface area of liquid wax. A wick that does not reach the wall gives a small pool and a quiet candle, so an under-wicked candle smells of nothing however much oil is in it.

The other cause is a load above the wax's capacity: unbound oil sits on the surface and does not reach the flame, so more oil has made it quieter.

Diagnosing which

Good cold, poor hot: look at the wick and the melt pool first.

Poor cold, poor hot: cure time, then load, then the oil itself.

Good cold, poor hot, plus oil on the surface: the load is above capacity and the fix is less, not more.

References