How to run a wick test that actually tells you something

Every wick chart comes with the same warning: test it. The chart was built with one oil, one load, no dye and one jar. Yours will be different. A wick test is how you close the gap, and done properly it only takes a few evenings.

Step 1: pick three sizes

Find your jar’s inside diameter at its widest point. Look up your wax on your supplier’s wick chart and take the suggested size. Then add one size smaller and one size larger in the same series.

The wick test planner does this from the CandleScience chart: choose your wax, enter the diameter, and it lists the three wicks. If your jar falls between two chart sizes, start from the smaller one.

Step 2: pour all the test jars from one batch

The only thing that should differ between jars is the wick. Use the same wax, oil, load, dye and pour temperature. Two jars per wick size is better than one, because a single jar can be a fluke.

Mark the wick size on the bottom of each jar with a marker or a sticker.

Step 3: cure

Soy wax often needs one to two weeks to reach full scent and a stable burn. Paraffin blends are usually ready sooner. Testing too early can make a good wick look weak.

Step 4: the four-hour burn

Set the jars on a heat-safe surface, a few inches apart, away from vents and fans. Light them all at the same time and check every hour. CandleScience suggests sessions of about four hours.

At each check, note:

• How wide the melt pool is, and whether it reaches the edge
• Flame height, and whether it flickers or smokes
• Whether the wick is mushrooming
• How hot the glass feels near the top

Let the jars cool completely, then repeat. Keep going until each jar is down to about half an inch of wax. The last third of the jar is where an oversized wick shows itself.

Step 5: read the results

Too small: the melt pool never reaches the edge in four hours, the candle tunnels, the scent is faint.

Too big: a tall or dancing flame, black soot on the glass, a heavy mushroom, a jar too hot to touch near the rim.

Right: the pool reaches or nearly reaches the edge by the end of the burn, the flame is calm, and the jar stays manageable all the way down.

When to test again

Any change can move the right wick by a size: a new oil, a higher load, a darker dye, a different jar. Heavy fragrances and dark colors often need one size up. Keep your burn logs; the second time you test a similar candle, you will know where to start.