I’m Using a 10 cm Wide Jar and One Large Cotton Wick Overheats the Centre — Should I Test Two Smaller Wicks Instead?

Why one big wick overheats the middle of a wide jar

A wick's flame melts a roughly round pool that spreads from the wick outwards. In a 6 or 7 cm jar the glass is 2.5–3.5 cm from a centred wick, and a modest flame reaches it in a normal session. In CSI's 10 cm listing, read as the outside with a 0.35 cm wall, the glass is 4.65 cm away and the surface is 67.93 cm², about 2.2 times the whole pool of a CSI 7 cm listing. To melt all of that from one point, the wick must deliver a lot of heat to a small area first.

What happens next is common in wide single-wick candles, and it is what "overheats the centre" usually means: the pool under the wick gets deep (well past the 0.5–1 cm many makers aim for), the flame grows, carbon may cap the wick, and the edge is still solid or only just melting when the session ends. The wick is too big for the centre and not big enough for the edge at the same time. No single size solves both, which is why the next step is a second wick, not a third single size.

A pair changes the problem. Two wicks on a line through the centre each look after half the pool, and each sits about 2.33 cm from the wall along the wick line instead of 4.65 cm. Each can be smaller, the heat is spread over two points, and the centre no longer carries the whole candle. The trade-offs are real: two flames heat each other and the strip between them, total heat can be higher than with one wick, and the two wall points at right angles to the wick line stay the furthest from any flame. That is why this page tells you to test a pair rather than switch to one. How to read a leftover ring on a pair is the ring-shape post.

The oil matters, within limits. Spiced, vanilla-rich or resinous oils are commonly linked to needing more wick, and makers who push a single wick up to compensate are the ones who meet the hot centre. The worked example uses Autumn at 8%, inside its page's "Recommended fragrance load 7-11% for candles" and below CSI 464's "up to 10%" (the lower of the two ceilings governs), so the load is not the lever here. If your oil is vanilla at 10% and the wicks mushroom, that is the vanilla double-wick post.

CSI's 10 cm jar, and the 11–12 cm gap

The Apothecary Glass Candle Jar with Dome Lid is the only CSI container listing with a 10 cm diameter figure. Its page says "Diameter (outer rim): Approx. 10 cm", "Base diameter: Approx. 10 cm", "Height (without lid): Approx. 10.8 cm" and "Fill capacity: ~500 g - 700 g (2 sizes)", and it states "Safe for hot-pour up to 85°C". It is sold as 500 gm (₹212.40) and 700 gm (₹250.00), both in stock on 29 September 2026.

Three things the listing does not tell you. It gives the outside, not the inside, and it calls the jar "thick-walled": on our series' 0.35 cm wall the inside is 9.3 cm; at a 0.5 cm wall it would be 9.0 cm and 63.62 cm². It gives one set of dimensions for two capacities, so we cannot tell you from the page how 700 g fits the same outline. And the 85°C wording is a pour limit: it says nothing about how hot the glass may get while burning. With CSI 464, whose page says "Pour Temperature 80°C – 90°C", pour at 80–85°C in this jar.

The 11–12 cm gap. CSI lists no jar at 11 or 12 cm by any stated diameter. The nearest is the Reusuable Premium Glass Clip Top Airtight Glass Candle Container (₹229.00, "Wax Fill - 550g"), whose page says "Dimension- 11cm * 11cm * 10cm" without saying which figure is the height or the diameter, and states no heat wording in the text we captured. We will not tell you it is an 11 cm jar. Posts 4271–4280 are written for your own 11–12 cm jars; on a 0.35 cm wall an 11 cm outside is 83.32 cm² inside (23% more than our 10 cm) and a 12 cm outside is 100.29 cm² (48% more). Ask us on WhatsApp if you want a wider jar; we would rather say "not listed" than sell you the wrong one.

The 10 cm configuration starter: one, two or three wicks

Here is the arithmetic that a 10 cm test starts from: pool area to the glass, the area each wick serves, and where the wicks sit at a labelled starting spacing. For a pair, the starting spacing puts each wick halfway between the centre and the glass, centre to centre equal to the inside radius. For three wicks, the starting point is a triangle on a circle of radius r/2. Both are geometry and starting points for testing, not burn predictions and not CSI data.

Two things stand out. First, each wick of a pair serves 33.96 cm², a little more than the whole pool of a CSI 7 cm listing (31.17 cm² on the same wall assumption), which is why the pair arms in this cluster start with the wicks you would compare in a 7 cm jar. That translation, and why reading a single-wick chart at 10 cm misleads, is the first-two-sizes post. Second, each of three wicks would serve 22.64 cm², about the whole pool of a CSI 6 cm listing (22.06 cm²): three small flames in a 10 cm jar is a lot of total heat for the surface, so three wicks are not in this test. When a third wick earns a place is the three-wick threshold post.

Spacing is its own variable. If your pair arms are inconclusive, the spacing ladder belongs to a separate test; don't change size and spacing in the same candle. Placement templates for three wicks are in the 12 cm placement post.

The pair-against-single test, costed

Hold everything but the wick build: the same wax bag, the same oil and load on total weight, the same jar batch, 500 g fill, pour temperature, cure and room. The worked example uses CSI 464 and Autumn at 8%: 500 g = 40 g of oil + 460 g of wax. Two candles per arm is the minimum that shows an odd candle; three is better if your budget allows, and at this size a third candle per arm adds ₹674.72 or more in materials.

Per candle, before stickers: ₹674.92 on one Cotton Braided, ₹674.72 on two C1 and ₹681.80 on two C2 (₹217.12 of oil, ₹233.40 of wax, ₹212.40 of jar and the wicks). The wicks are the smallest line: a C1 pair costs ₹0.20 less than one Cotton Braided, and a C2 pair ₹6.88 more. Costs are worked examples and exclude labour, freight, packaging and GST. From nothing, the cash outlay is ₹5,943.00; the 260 g of oil left covers 6 retest candles.

Reading the result, and when to buy nothing

Thresholds are our judgement, chosen because they can be read with a ruler and a skewer; the depth and flame figures are commonly cited rules of thumb. Keep your standard fixed across all six candles. A pair that reaches the glass within an hour is the opposite problem, and the one-hour pair post owns it.

Buying list for the 10 cm pair test

Six items, in the order the test needs them, chosen on page statements, price and stock on 29 September 2026. CSI publishes no wick-performance data, so nothing here is ranked on burn results. Oil candles are counted at 40 g (500 g fill) and 12 g (150 g).

Map of this cluster: 4261–4280

This page owns the short answer, the 10 cm configuration starter, the pair-against-single test and CSI's honest jar gap. Each other post owns one test for one situation in 10–12 cm, multi-wick candles.

Coming from 8.5–9 cm jars? The previous hub is the thick-ring, single-or-double post. Planning several jar sizes at once is the commercial wick-matrix hub.

Frequently asked questions