My 7.5 cm Jar Has a Huge Flame with the Recommended Wick Size — Should I Test One or Two Sizes Smaller?

Why the "recommended" wick is only a starting rung

Your symptom, stated exactly: a 7.5 cm jar, burning with the wick size you were told to use, and the flame is huge, well beyond the 2.5–5 cm many makers use as a practical rule of thumb. The recommendation might have come from a supplier's chart, a jar listing or a friend's candle. It was made without your wax, your oil, your load, your fill height or your room. Any of those can push the same jar from one wick to another.

CSI's own pages show how loose these recommendations are. The coloured 200 ml Salsa jar pages say "Pairs well with C2 Eco Wicks". Our tin container page, whose larger size is described as "7.5 cm x 5 cm", suggests "medium cotton or wooden wicks", and we sell no wick called "medium". Cotton Braided's page says "engineered for large-diameter candles exceeding 8 cm". Each of those is a reasonable first rung to test. None is a burn result, and we wouldn't want you to treat ours as one. If your recommended wick is from another supplier's range, don't try to match its name to C1 or C2 either: wicks with similar names from different makers can burn quite differently (the supplier-change post). Treat your current wick as the control and test CSI's rungs against it.

Fragrance matters too, and it's a tendency rather than CSI data. The same 7.5 cm jar can need different wicks for a light floral and a dense vanilla or oud. That is why the 7.5 cm posts in our wick-diagnosis series exist: 7.5 cm lavender tunnelling for two burns, through to a 1 cm-deep pool at four hours. If you sell several scents in this jar, the wick that passes for one is a starting rung for the next, not an approval.

Your 7.5 cm jar, measured both ways

Most listings give an outside or unstated diameter. Measure the inside at the wax surface and near the base. The two readings, using a 0.35 cm wall as a labelled assumption, are geometry rather than burn predictions:

Reading A has 21.6% more pool to melt than reading B. That is why a wick recommended for "7.5 cm" can be right for one jar and far too strong for another. On either reading, the jar is below the "exceeding 8 cm" that Cotton Braided's page positions it for, so a huge flame from Cotton Braided here is unsurprising. On reading B, a C1 pair sits under 2 cm from the glass, which is why it's a round-2 contingency to test, not a default.

Be clear about what CSI lists near this size. No in-stock CSI glass jar states 7.5 cm. The Glass Jar With Bamboo Lid gives "W:7.5 cm" but is out of stock on 7 October 2026. Our tin container's larger size is "7.5 cm x 5 cm", and the page doesn't say which figure is the diameter. Our common 150 g glass jars give an outer diameter of about 7 cm. So your 7.5 cm jar is your own, and a result from our 7 cm jar is not a result for yours. A 5 mm change in jar diameter can be enough to justify a retest (the 7.5-to-8 cm retest post).

Before you buy: the cause ranking for a huge flame

If the flame is too large even after a correct trim in still air and you want to prove it's oversized before buying anything, the trimmed-but-still-large post has the evidence rule. If it is fine for an hour and grows by hour three, start at the hub. This post assumes you are past that point and the question is simply how far to step down. Two exceptions: a huge flame over a pool that doesn't reach the glass is the tall-flame, short-pool problem, where stepping down backfires; and a full pool in well under an hour is weighed in the under-an-hour post.

The side-by-side plan: rounds, candles, approval

Why test both at once, in rupees. Adding C1 to round 1 costs three more candles: about ₹70.02 of CSI 464 and ₹41.06 of British Rose each (₹111.08 a candle, your jar extra), so ₹333.24 for three, or ₹451.24 with the C1 20-pack. Leaving it out risks a second round of about 10 days, 20 in all, if C2 turns out still too strong. With festive orders waiting, that trade is usually easy. How many rungs to test in general is the adjacent-sizes post's subject; in CSI's short range, the answer for a 7.5 cm jar on Cotton Braided is simply "both of the other two".

The CSI buy list and the production step

CSI's sized, tabbed wicks are C1 → C2 → Cotton Braided. There is no sized, tabbed wick between C1 and C2 or between C2 and Cotton Braided, no smaller sized, tabbed wick than C1, and one wooden-wick listing with no widths. The untabbed options (Eco Braided Wicks by the metre, the Braided Wick Roll with 100 tabs at ₹706.82, and the Eco Candle Wicks Loose, "designed specifically for 2 inch diameters") are cut-to-length constructions, not half-sizes. If your 7.5 cm jar falls between C1 and C2, we would rather tell you than sell you a third pack.

Argued against our own interest: you don't need the Cotton Braided 10-pack if you are already burning ours. It's your control, and you have it. Nor do you need more than ₹212.40 in wicks for the whole plan. Stepping down also cuts your wick bill: at a worked-example 200 candles a month plus 2% (204 wicks), Cotton Braided would be ₹2,520.00 a month (2 × 100 + 10), C2 ₹1,982.40 (210 wicks) and C1 ₹1,298.00 (2 × 100 + 20). That is ₹537.60 a month less on C2 than on Cotton Braided. Nice, but never the reason to pick a wick: the full-life result is.

Buy production wicks only after approval, by the month; reorder point = daily use × your lead time + safety stock. CSI publishes no lead times, so ask on WhatsApp. If a later delivery burns differently, retest before production (compare wick lots).

What to buy, and what to skip

Five items, chosen on page statements, price and stock on 7 October 2026. CSI publishes no burn, flame or wick-per-jar data, so nothing here is ranked on performance, and each card says when not to buy.

Skip for now: the steel holders until round 1 says you need a pair; any 100-plus pack before approval; a new jar mid-test; and a new oil while the wick question is open.

Frequently asked questions