My 8.5 cm Double-Wick Candle Melts the Surface Extremely Quickly — Does That Mean the Two Wicks Are Collectively Oversized?

Why "fast" is the wrong alarm for a pair

Most melt-pool rules of thumb were written for one centred wick. The best known, about an hour of burning per 2.5 cm of jar width, is very rough even there. A pair breaks it by design: each wick only has to melt its own half, and two flames put more heat into the same wax. So a pair that meets the glass in 45 minutes may be doing exactly what you asked. Treat a fast full pool as a prompt to look at four other things, not as proof of over-wicking; a fast pool alone isn't proof.

If every row reads "fine", the fast melt is not a fault. Carry the candle on through its full life, because pairs commonly run warmer in the lower half of a jar, and judge it there. If any row reads the other way, the question in the title is fair, and the single-lit test is the cheapest way to answer it. What the equivalent test looks like for a 10 cm pair that pools inside an hour is the 10 cm fast-pool post; how single wicks show over-wicking in a small jar is the 6 cm fast-pool post.

The distances the test is read against

CSI lists no 8.5 cm jar, so measure yours from the inside, at the wax surface, mid-height and near the base; the method is in the 8.5–9 cm hub. Our worked example reads 8.5 cm as the outside with an assumed 0.35 cm wall: 7.8 cm (78 mm) inside. Then measure your actual wick positions at the surface of a cured candle, centre to centre, because wicks drift while wax sets and the spacing you glued is not always the spacing you burned.

Our 39 mm is a spacing equal to the inside radius, a common-sense starting point that puts each wick as far from the wall as from the midpoint. Yours may differ; do the same sums on your own measured spacing: to the near wall = inside radius − spacing ÷ 2, to the midpoint = spacing ÷ 2. The single-lit reading compares the lone pool with those two numbers.

The single-lit diagnostic, step by step

You need twins of the candle that races: same wax, oil, load, fill, wicks and spacing, cured the same time. Our worked example is 250 g at 8% British Rose (20 g + 230 g of CSI 464) on 2 × C2 at 39 mm. Pour three: twin 1 for wick A alone, twin 2 for wick B alone, twin 3 as the both-lit reference if you don't already have a logged burn. The single-lit twins are diagnostic candles only; their lopsided history makes them useless for a full-life test afterwards.

Why 60 minutes? Because it is long enough for a lone pool to show its reach and short enough that the pool hasn't simply spread by conduction across the whole jar. It is our choice, labelled as such; keep it fixed for every twin you compare. CSI 464's page states "Pour Temperature 80°C – 90°C"; your jar has no CSI heat wording, so pour at the low end into clean, evenly warmed jars (our judgement). The British Rose page states no cure time in the text we captured; the 25 of 102 CSI oil pages that do say 48–72 hours for soy, and many makers wait about a week.

Three readings and the step each one earns

Divide the lone pool's radius toward the near wall by the wick-to-wall distance. The bands below are our judgement, drawn from the geometry, not from CSI data; the flame reading keeps them honest.

Why "together too hot" is a spacing fix first. If each wick alone is modest and calm, its size isn't the problem; two modest pools overlapping in the middle are. The heat from both flames stacks where the pools meet, the centre deepens, and the flames lean in towards the hot spot. Moving them apart reduces the overlap. It also brings each wick 2.5 mm nearer the wall (19.5 → 17.0 mm), which is why you test the move rather than assume it; wall heat is the wall-gap post's subject. If moving apart cools the centre but the sides start to lag, the pair was also a touch too big, and a size step becomes a fair second move.

Why "each too big" is a size fix, not a spacing one. A wick whose own pool reaches the wall in an hour and crosses the midpoint doesn't need its partner; moving it anywhere puts it nearer glass or nearer the other flame. Step both down one rung at the same spacing. At CSI that is 2 × C2 to 2 × C1, saving ₹7.08 a candle, ₹7,080.00 per 1,000 candles.

Running the matching step

Whichever branch you are on, the step is one change, two candles, against two controls on your current build, poured and cured together and burned in alternating order in one still room. Log the same things as the reference: time to a full surface, depth at 1 and 2 hours, flame heights and lean, caps, soot, and the sides at right angles to the wick line at the end of each burn.

On the pair-down branch, materials consumed are ₹517.63 of British Rose (140 g at the ₹3.70/g average of a 100 g + 50 g purchase, ₹554.60; 10 g left), ₹816.91 of CSI 464 (two 1 kg bags, ₹1,014.80; 390 g left), ₹94.40 of C2 and ₹23.60 of C1: ₹1,452.54, jars excluded. The diagnostic round on its own is ₹628.59. From nothing, the cash outlay is ₹1,899.80 including a pack of centring bars. Per candle, excluding the jar, a 2 × C2 candle is ₹209.53 and a 2 × C1 candle ₹202.45. Costs are worked examples and exclude labour, freight, packaging and GST.

Setting a new spacing without a new holder

On the spacing branch, a fixed-hole holder is no use unless its holes happen to sit 44 mm apart. Two Wick Centering Device bars laid parallel across the rim, one wick in each hole, give you any spacing you can measure: mark the two positions on a paper template on the jar base, stick the tabs, then set each bar so its wick stands straight over its mark. Measure centre to centre again once the wax has set.

The "extremely quickly" in your question will not necessarily go away, and it doesn't need to. A right-sized pair still melts faster than a single; what you want is the depth, the flames and the glass to be calm for the whole life of the candle, observed and never judged by touch. When a pair comes out of this test tied with a single, weighing them against each other is the scorecard post.

What to buy, and what to skip

Five items, in the order the branches need them, chosen on page statements, price and stock on 29 September 2026. CSI publishes no wick-performance data, so nothing is ranked on burn results. Oil candle counts use the 250 g worked-example fill (20 g each) and the standard 150 g candle (12 g each).

Frequently asked questions