Reverse taper, throw over time & stability
Five consequences of flaring a candle vessel outward.
A tulip flares outward toward the rim, which means the melt pool is at its widest when the candle is new and narrows steadily as it burns down. That is the opposite of a tapered jar, and it changes both the wicking strategy and the way fragrance throw behaves over the life of the candle.
The first burn is the hardest one
With the widest diameter at the top, a wick that cannot reach the wall on the first burn tunnels immediately and never recovers. As the pool descends into narrower glass, the same wick becomes progressively more than sufficient. Wick sizing therefore targets the rim, and the end of the burn is checked for excessive glass temperature.
Fragrance throw declines as the candle empties
Throw scales with the exposed melt surface, and in a tulip that surface shrinks continuously. A candle that fills a room when new can seem quiet when half gone, without anything being wrong with it. Setting that expectation, or accepting it as a characteristic of the shape, is more honest than chasing it with fragrance load.
The flame is well supplied with air
A wide, open mouth gives good circulation to the flame throughout the burn, which is the opposite problem from a bellied or narrow-necked vessel. That makes tulips forgiving of larger wicks and suits waxes and fragrance loads that would smoke in a restricted vessel, and it is a genuine technical advantage of the shape.
Stability needs attention at the base
Flaring outward moves mass away from the center line and upward, so the footprint is the narrowest part of the vessel while the weight sits above it. A heavier base or a wider foot compensates, and filled tipping tests on a slightly inclined surface are worth doing before the format is committed.
Lids are difficult and often omitted
A wide flared rim needs a correspondingly large lid, which costs more, weighs more and looks out of proportion on a small candle. Many tulip candles are therefore sold unlidded, and the fragrance retention that a lid would have provided during storage has to be found elsewhere — usually in a sealed carton or a wrap.
The flare makes the jar hard to pack and easy to chip
An outward-turning rim is the widest and thinnest part of the vessel and it sits proud of everything else in the carton. Dividers that support the rim rather than the body, and a carton sized to the flare, are what keep the breakage rate reasonable.
