My Candle Uses Two Wicks and the Glass Gets Much Hotter Than My Single-Wick Candle — Should I Change the Jar or Wick Configuration?

Why two wicks run the glass hotter

Makers usually add a second wick for a good reason: a wide jar that one wick couldn't melt to the edge, or a stronger hot throw. The glass getting hotter is the price, and it comes from four places. All are common tendencies rather than certainties, and all are testable.

More flame in the same space

Each flame burns wax. Two flames of the same size burn roughly twice as much per hour as one, and the heat goes into the same wax and the same glass. If the two wicks are each as large as the single wick you would have used alone, the jar is receiving far more heat than it needs to melt its pool.

Each flame is closer to a wall

A centred single wick is as far from the glass as it can be: half the inside diameter. Move to two wicks and each one must sit off-centre, closer to the wall on its side. The diagram shows it in a 9 cm inside diameter: 4.5 cm for one wick, 3 cm for two wicks 3 cm apart, 2.25 cm at the quarter points, 1.5 cm if they're 6 cm apart. The closer a flame sits to glass, the more directly it heats it, and a flame touching the glass is a common cause of cracks.

One big pool, sooner and deeper

Two pools grow toward each other and merge. Once they do, the whole surface is liquid, and a large liquid pool can deepen quickly. A deep pool fuels taller flames, and taller flames heat more of the glass above the wax. A pool depth of about 0.5 to 1 cm is a rule of thumb for a well-sized wick; a pool much deeper than that in a two-wick candle is a sign the pair is oversized.

Flames affect each other

Two flames close together commonly burn taller and less steadily than either would alone, because each sits in the other's rising hot air. They can also lean away from each other, toward the glass. That is one reason drift matters more with two wicks than one. Fragrance load can play a part in flame behaviour too, but wick and jar usually dominate; that question is Can Fragrance Load Affect How Hot a Candle Jar Becomes During a Burn Test?.

First, is the comparison fair?

"Much hotter than my single-wick candle" is only meaningful if the two candles differ in wick count and nothing else. Often they don't. Check this before you change anything.

Spacing: the gap between each flame and the glass

The quantity that matters is the gap from each wick to the nearest glass: half the inside diameter minus half the distance between the wicks. It is simple arithmetic, and it tells you quickly whether a jar is a sensible home for two wicks. A common starting layout puts each wick at a quarter point, halfway between the centre and the glass; that is a place to start testing, not a rule.

Two things stand out. In narrow jars, two wicks leave a small gap whatever you do: at 7 cm inside, the quarter points are 1.75 cm from the glass, and "wider apart for a better pool" quickly becomes "flames at the glass". And in every row, pushing the wicks further apart than the quarter points buys pool coverage at the cost of the gap. If your two-wick jar runs hot and the wicks are wider apart than the quarter points, bring them in before anything else. The "our reading" column is judgement; whether your jar needs one, two or three wicks at all is I'm Buying a 4-Inch-Wide Luxury Candle Jar — Should I Plan for One Wick, Two Wicks or Three Before Ordering Production Quantities?.

Measure where the wicks really are

Wicks drift. A tab can slide during the pour, and wicks lean as the wax softens. After the first burn has cooled, measure from each wick to the nearest glass at the wax surface with a ruler. If either is noticeably closer than you set it, the heat you are seeing may be drift, not design. Fix the tabs with wick stickers on marked positions and hold the tops in a bar or centering device while the wax sets.

The fix order: configuration before jar

Changing the jar is the most expensive fix: new stock, new measurements, a new burn-down, maybe new packaging. So change it last. Here is the order we would work in, with what each step can and can't fix. Change one thing at a time.

Step 3 deserves a note. Two smaller wicks are often better than one huge wick that soots (My Large Candle Jar Needs a Huge Single Wick That Produces Soot — Would Two Smaller Wicks Be a Better Choice?), but a jar in the 8 to 9 cm range can sit on the border, where a single larger wick pools it without crowding the glass. The only way to know is to test both. Retest every change to the stop line, because a configuration that looks fine in the top third can still overheat in the final third (Why Is Testing the Final Third of a Candle Important Before Approving a New Glass Container for Commercial Sale?).

The side-by-side test: two small, two current, one

This test answers "jar or configuration?" directly. Same jar, same wax, same oil, same fill; three wick layouts; two jars each. Burn on a heat-resistant surface, in sight, never unattended, away from draughts, children, pets and anything that can catch fire. The worked example uses the Apothecary 500 gm jar with 500 g candles at 8% (460 g wax + 40 g oil each).

Picks: a wide jar, spacing tools and three wick options

Five items, chosen on what their pages state, price and stock on 26 September 2026, not on test results: CSI has none for these jars or wick layouts. Wax for the worked example is Luxury Soy Wax CSI 464 (₹0.51 per gram at 1 kg, 5 kg and 10 kg alike), and the oil is Woody Oud Fragrance Oil (₹4.53 per gram at 100 g, 500 g and 1 kg alike). Test with the oil you will sell. If you are not using the Apothecary jar, the same method works in any wide jar; the clip-top container lists "11cm * 11cm * 10cm" without saying which is the height, so measure first.

What the comparison costs, and Christmas timing

For scale, one finished 500 g candle in this jar costs about ₹638.85 in materials with two C1s (jar ₹212.40, 460 g of wax at the 10 kg price ₹233.40, 40 g of Woody Oud at the 1 kg price ₹181.25, two wicks ₹11.80) or ₹639.05 with one Cotton Braided wick, excluding labour, freight, packaging and GST. The wick choice moves the cost by paise; the heat is what matters. Buying the 5 kg sack instead of three 1 kg packs saves nothing per gram on CSI 464.

Christmas falls on 25 December 2026, 90 days after these prices were checked, and large two-wick candles are a natural gift format. The three-arm test plus a three-jar confirmation takes three to four weeks with cure and cool-downs; our judgement is to have the configuration decided by mid-November and pour production by early December. Dispatch is from Pune; confirm delivery time on WhatsApp.

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