My Large Candle Jar Needs a Huge Single Wick That Produces Soot — Would Two Smaller Wicks Be a Better Choice?

Why a big single wick soots

A candle flame burns wax vapour drawn up the wick. When the flame gets more fuel than it can burn completely, some leaves as fine carbon: the black film on the glass, the smudge under a lid, the wisp above a flickering tip. A big wick in a wide jar is chosen to push enough heat outwards to reach the wall, and to do that it pulls a lot of fuel. That is why soot tends to show up first in wide jars that rely on one big wick.

Only the last row is a case for two wicks. The first four have cheaper fixes, and a second wick would hide them rather than solve them. If you raised the load hoping for more scent and got soot instead, how load and wick size interact is in the post on load and wick size.

Single vs double: what you gain and what you pay

When a wide jar has outgrown a single wick, a second wick changes more than the flame size. The table is the honest ledger. Most rows are tendencies that vary with wax, oil and wick, which is why the test follows.

The rows that matter most are total heat and wax per hour. A double-wick candle that pools beautifully can still make the glass uncomfortably hot, and it will burn for fewer hours than the same candle on one wick. If you print a burn time, measure it on the setup you sell. When two wicks make the glass much hotter than one, the configuration-versus-jar question is covered in My Candle Uses Two Wicks and the Glass Gets Much Hotter Than My Single-Wick Candle — Should I Change the Jar or Wick Configuration?; heat that builds only near the end of a double-wick jar is covered in My Double-Wick Candle Burns Too Hot Near the End of the Jar — Could the Container Shape Be Contributing to the Problem?.

How two wicks cover a pool differently

Worked example: the Apothecary Dome jar is listed at 10 cm across the outer rim. If the walls were about 0.35 cm, the inside would be about 9.3 cm and the pool about 67.93 cm², 117.9% more than a 6.3 cm jar's 31.17 cm². A single wick at the centre has to push heat 4.65 cm to the wall in every direction. Two wicks share that surface, about 33.96 cm² each, and each flame sits much closer to the wall on its own side.

The catch is the sides. The wall midway between the two wicks, at right angles to the line joining them, is further from each wick than the wall at the ends is. In a double-wick candle that is usually where the last solid wax clings: the pool goes from two circles, to an oval along the wick line, to full. Watch those two points in every test, because a double wick that leaves them solid has swapped a tunnel for two ledges. How far apart to set the wicks, and when a third wick starts to make sense, is the geometry question in I'm Designing a Three-Wick Candle — How Wide Should the Jar Be Before Three Wicks Make More Sense Than Two?; whether a 4-inch jar should be planned as one, two or three wicks before you buy production quantities is in I'm Buying a 4-Inch-Wide Luxury Candle Jar — Should I Plan for One Wick, Two Wicks or Three Before Ordering Production Quantities?.

The side-by-side test, step by step

This assumes steps 1 to 3 on the flowchart are done: the big wick is trimmed, out of draughts, at a load inside the ceiling, and still sooting while it struggles to reach the glass. Burn test candles on a heat-proof surface, within sight, never unattended, and away from anything that can catch fire.

What the test and each setup cost

Worked example in the Apothecary Dome jar, 500 gm size, filled to the listing's "~500 g" (weigh your own). At 8%, each candle is 40 g of oil and 460 g of wax. Round one is three candles (A, B, C); round two duplicates the leader, costed here as two C2, the dearest pair. Oil is Roasted Coffee Fragrance as a costing example only (page: "candles (6-10%)"); wax is Luxury Soy Wax CSI 464 (page: up to 10%).

Two notes on the basket. Two 100 g bottles of oil are the right size here: a 500 g bottle is cheaper per gram (₹3.78 against ₹3.90) but costs ₹1,110.00 more up front for a 160 g test, and you may not choose that scent for production. And the wax: CSI 464 costs ₹0.51 per gram whether you buy 1 kg or 10 kg, so two 1 kg bags cost exactly what 2 kg from a larger bag would. If you already own the jars, the kit is ₹2,286.20.

What each setup costs in production

Per 100 candles, wicks are ₹1,200.00 for single Cotton Braided, ₹1,180.00 for pairs of C1 and ₹1,888.00 for pairs of C2 (₹688.00 more than single Cotton Braided). On a 500 g candle carrying ₹382.92 of wax and oil at bulk prices, that difference is small. The costs that matter are the ones on the right of the flowchart: shorter burn time from two flames, which changes what you can claim on a label, and more heat into the glass, which changes what you must test. Costs exclude labour, freight, packaging and GST.

Wicks, tools and a wide jar for the single-vs-double test

The control wick, the pairs, the tool that holds two wicks where you meant them, the trimmer for step 1 and a wide jar to run it in. Chosen on what the pages state, price and stock on 26 September 2026; CSI publishes no soot or burn data for any wick and jar pairing.

After the test: reading the result

Whichever wins, finish with the final third. Two flames closer to the glass is where a double wick tends to show its cost. If your jar is wide but a single wick tunnels rather than soots, the fix order is different: see My Candle Burns Perfectly in a Narrow Jar but Tunnels in My Wider Jar Using the Same Wick — What Should I Change First?. If the question is how to pick the first wicks to test in a new jar rather than rescue an existing one, start with I Have a Straight-Sided 3-Inch Candle Jar — How Do I Choose the First Three Wick Sizes to Test Rather Than Guessing Randomly?.

Frequently asked questions