My 7 cm Lavender Candle Has a Good Flame but Weak Hot Throw — Should I Increase Wick Size Even Though the Melt Pool Already Looks Correct?

Why the answer is usually no

Think about what the wick controls. It controls how much heat goes into the candle, and so how wide and deep the pool is and how big the flame runs. Once the pool reaches the glass at a sensible depth (about 0.5–1 cm is a common target), the surface area releasing fragrance is as large as this jar allows: about 31.17 cm² on a 6.3 cm inside, on our 0.35 cm wall assumption. A bigger wick cannot make that surface larger. It can only make the pool hotter and deeper, and the flame bigger.

A hotter pool may release fragrance somewhat faster, and makers do sometimes report a stronger room with a larger wick. The problem is what comes with it. Commonly: a taller flame, more carbon on the wick (mushrooming), soot on the glass and in the room, a deeper pool as the candle burns down, and a hotter jar in the final third. Some of that may even be what you are smelling: a hotter, sootier flame can change how a scent reads. That is why the trial below treats every heat sign as a veto.

The more common reasons a well-burning candle smells weak are elsewhere: the room is large or ventilated, the candle was burned before it cured, the tester has been smelling it for an hour, or the oil or load is not giving what you expected in this wax. How a 7 cm surface limits a big room is the surface-area post; how to decide whether it is cold throw or hot throw that is weak is the cold-versus-hot diagnosis.

Four free checks before any trial

Also confirm the pool really is correct. Measure its depth at 3 hours near the wall; confirm it meets the glass all round by burn 2 or 3; and note the trimmed flame height. If the pool is actually shallow or leaves a ring, you have an under-melt, not a throw problem, and the order of operations changes: see the catch-up rule. If the pool is deep and fast, your wick may already be on the large side, and bigger is the wrong way.

The stop conditions that void a throw gain

Write the stop conditions down before you light anything, so a pleasing smell cannot argue you out of them later. In this trial they apply to every C2 candle, every burn, through the full life. If any one trips, that candle's throw scores are struck out. If two of the three C2 candles trip, C2 is out.

If you want a number for glass temperature, it needs a non-contact thermometer; CSI does not list one, so say so in your notes rather than guessing by hand. The black matte jar in this worked example makes soot on the wall harder to see; check from above with a torch. Heat questions where the throw is already strong are the hot-glass step-down post, and how a stronger smell can mask a poor burn is the over-wick masking checklist.

Blind, coded, fixed distance: the throw protocol

This is the smallest protocol that gives a fair answer to one question: does C2 smell stronger than C1 in this jar at this load? A fuller method for objective hot-throw testing is the objective hot-throw post; here is the version sized for a six-candle trial.

Running the six-candle trial

Pour all six from one melt: Lavender at 8% of total weight (12 g of oil + 138 g of wax per 150 g candle), CSI 464 from one bag, jars from one batch, same pour temperature, same stir, same cure. Three candles on C1 (your current wick, the control) and three on C2. Cure all six the same number of days; we would wait about a week and score burns 2 and 3.

Per candle: ₹211.52 on C1, ₹215.06 on C2 (₹64.80 of Lavender, the wax, ₹70.80 of jar, the wick). From nothing, ₹1,967.80; if you own everything but C2, ₹94.40. Costs are worked examples and exclude labour, freight, packaging and GST. The real cost is time: burns 1–3 on six candles are 18 sessions of about three hours, one candle per room at a time, before full life begins.

Burn every candle in still air, trim to about 5–6 mm before each burn, and log at 1 hour, 2 hours and the end of each session: pool width and depth, trimmed flame height against a ruler, carbon on the wick, soot, flame-to-glass distance, and the throw score from the coded assessment. At about 2.5 hours by the rough one-hour-per-2.5 cm rule, a 3-hour session is long enough for the pool to settle.

After the trial: what each result means

If C2 wins, it wins narrowly: in this jar, with this oil, at this load. It is not "the 7 cm wick". If you sell the same jar in heavier oils, those need their own brackets; if you sell it in lighter oils, C2 may be too much for them. The bracket-closure rule for production is the adjacent-sizes post.

What to buy, and what to skip

Four items for the trial, chosen on page statements, price and stock on 29 September 2026. CSI publishes no wick-performance or throw data, so nothing is ranked on results. Oil candle counts are per 150 g candle at 12 g (8%) and 15 g (10%).

Frequently asked questions