My 7 cm Candle Burns Well at the Top but the Flame Becomes Larger Halfway Down the Jar — Should Wick Testing Continue Through the Entire Candle?

Why the top half can't approve a wick

Your candle burned well at the top. That is a real result: the wick melts the pool to the glass without tunnelling, and the flame is steady. But the conditions at the top are the gentlest the wick will meet. The glass above the flame is short and cool, the solid wax below soaks up heat, and each session starts from a cold candle. Halfway down, three things have changed, and all three are commonly reported by candle makers:

So "burns well at the top, grows halfway" is not a contradiction; it is the normal shape of a container candle's life, and the question is only whether yours grows too far. The stage-by-stage explanation, with what to measure at each depth, is the depth-stage map; the acceptance gates for how far down counts as "commercially acceptable" are how far down to burn a test candle. This post owns the part those two assume you already have: the calendar.

Can you shortcut the bottom? Partly. Bottom-zone shortcut candles pour only the lowest third of the fill so the late-burn zone shows up in a session or two. They are a screen that can fail a wick early; they never approve one. And a two-hour test on its own, however careful, is exactly the test your candle has already passed.

Your burn rate, measured after burn 1

Every full-life plan starts with one number you can only get from your own candle: how many grams it burns in an hour. It depends on the wick, wax, oil, load, room and session length, which is why no CSI page states it and why we will not give you one as fact. Measure it on burn 1:

Weighing also gives you a reproducible "halfway": 75 g of candle left, whatever the jar's shape. In a jar that narrows toward the base, halfway by weight sits a little above halfway by height, which is one more reason to log grams, not centimetres.

Where to stop: finding 1 cm by weight

Many makers stop a test burn with about 1 cm of wax left: common practice for glass containers, because heat near the base builds and the tab and glass bottom sit close to the flame. The question is how many grams that 1 cm is in your jar. A water test answers it in two minutes:

Why a spare jar and not the maths? Because CSI's 150 g jar page gives an outer rim of 7 cm and a base of about 6.5 cm but no inside figure, the base glass has its own thickness, and the tab takes some room. Two minutes with water beats any assumed geometry. Confirm by eye at the last session too: through clear glass the wax line is easy to see against the ruler.

How many days full life really takes

Sessions of 3–4 hours are common for a 7 cm jar: long enough for the pool to reach the glass (about 2.5 hours by the rough rule), short enough to be a realistic customer session (our judgement). With the burn-1 rate, the count follows: 127 g ÷ 6.5 g an hour = about 19.5 hours, which is 5 sessions of 4 hours or 7 of 3. After burn 1 you still have 101 g to go, 4 more 4-hour sessions.

The cool-down between sessions is our judgement: let the pool fully re-solidify and the jar come back to room temperature before relighting, because a session that starts warm is not the same test as one that starts cold. One session a day makes that automatic. Candles poured on a Thursday can reach a decision in under two weeks; if the wick fails in the lower half, the retest one rung down is a second, identical cycle, and two cycles back to back take about 24 days.

Three candles in parallel, one log

Burn the three candles at the same time, in the same room, lit within a minute of each other and set at least 30 cm apart so one flame's warmth doesn't reach the next jar (our judgement). They share the calendar, so three candles take the same 12 days as one; they cost three times the materials and, in our example, about 58.5 candle-hours of burning, all of it done while you are in the room. Burn within sight, away from fans, AC vents and open windows.

If your current candle, the one that grew halfway, is the only one you have, keep burning it to the stop with this log anyway: it is evidence. But pour three fresh candles from one batch for the decision, because a single candle cannot tell you whether the growth is the wick or that candle.

When the flame grows: what to record, what to decide

Draw your line before session 1 so the decision is not made by mood at session 4. Many makers use about 2.5–5 cm as a practical flame range and about 0.5–1 cm as a pool-depth target: commonly cited rules of thumb, not CSI figures. Here is how three candles might read in the worked example:

A second cycle one rung down costs ₹727.61 in materials for three more candles, and if you already have the jars, wax and the 14 g of oil left over, the new purchases are a C1 20-pack (₹118.00) and a second 50 g bottle of Palo Santo, of which 22 g (₹132.40) is used. Whether C1 and C2 together are enough evidence to call a bracket closed is the adjacent-sizes post; the hub for this cluster is the 6–7 cm hub. If the heat worry is about customers praising a strong candle whose glass gets very hot, read the throw-preserving step-down.

What to buy, and what to skip

Five items, chosen on page statements, price and stock on 29 September 2026. CSI publishes no burn-rate or wick-performance data, so nothing here is ranked on burn results. Oil candle counts use 12 g per 150 g candle at 8%.

Frequently asked questions