My New Wax Batch Is Slightly Harder Than the Previous One — Could That Change Wick Requirements Even If Everything Else Remains Identical?

Why hardness can move the wick

A wick is sized to deliver enough heat to melt a pool of a certain width and depth in a certain time. If the wax in the jar needs a little more heat to liquefy, or sets back more readily at the edge of the pool, the same flame opens a smaller pool. That is the mechanism by which a firmer lot could change wick requirements with everything else identical.

Soy lots do vary. The oil they are refined from differs by crop and source, and processing can shift the melting range and the way the wax crystallises as it cools. A few degrees of difference in where a lot begins to soften can be enough to change how a borderline wick performs in a wide jar. It is less likely to matter if your approved wick already has headroom.

So the honest answer is yes, it could, but two conditions have to be true. The lot has to be genuinely firmer when compared fairly, and the difference has to show up in your jar with your wick. Goods-in is where you check the first, and a small burn matrix is where you check the second.

A fair hardness check at goods-in

Hardness judged straight from a delivery bag is mostly a measure of temperature. Wax that spent a night in a cold vehicle or a winter storeroom will feel firmer and snap more cleanly than wax that has been sitting in a warm workshop, even if both came from the same lot. Flake size adds another trap: larger or denser flakes resist a fingernail more than fine ones. Take temperature and form out of the comparison before you judge anything.

If both judges rank the new lot firmer on all three checks, and the thermometer shows it melting or setting noticeably higher, you have a real difference worth testing in candles. If the rankings disagree or flip between checks, the lot is probably within normal variation and the original feel came from temperature or flake form.

The six-candle wick matrix

If the new lot is confirmed firmer, the next question is whether that matters in your product. A three-cell matrix answers it without testing every wick you own. Cell one is the old lot with your current wick: this is your reference. Cell two is the new lot with your current wick: this shows whether the approved formula still works. Cell three is the new lot with the next size up: this is only relevant if cell two falls short.

Worked example: a maker pours a 150 g apothecary-style candle with British Rose at 7% of total candle weight. Each candle takes 150 × 0.07 = 10.5 g of oil and 139.5 g of wax. Her approved wick is Eco Thin (C1); the next size in the same range is Eco Thick (C2). Two candles per cell is a suggested starting point to validate.

Burn all six on the same day in the same room. Measure melt pool diameter across two directions at fixed intervals, note flame height and any mushrooming, and look for soot on the glass. The finished candles are not wasted: keep one from each cell as a dated reference.

Reading the result and deciding

Two candles per cell will show a large difference clearly and a small one only faintly. If the pattern is borderline, for example cell two reaching the glass on one candle and falling short on the other, pour a second pair for that cell rather than guessing. A lot you are about to pour into hundreds of jars deserves one more evening of burning.

Whatever the matrix shows, the combination you finally release must also pass a full burn test to the end of the jar. Early hours show melt pool; the final third shows whether the glass overheats, the flame grows as the wick meets the tab, or soot builds up near the base. A firmer lot with a larger wick is exactly the combination where that final third needs watching.

A conditional release means the new wick is tied to this lot only. Write the lot and wick together on the bag label and on the batch sheet, and when the next delivery arrives, compare it against your original reference, not against the workaround.

If the lot is from CSI and you need to discuss it, message WhatsApp +91 7397976926 with your invoice date, product, pack sizes, the blind ranking and the matrix results. CSI product pages publish no hardness value or melt tolerance per lot, so your comparison is the evidence. Record the reply alongside your decision.

A note on firmness and Indian summers

It is tempting to welcome a firmer lot before the hot months, on the reasoning that it will hold up better in transit and on shelves. It might. But an unexplained change is still an unexplained change, and a firmer lot that needs a larger wick will also burn hotter once the room is warm. If you plan to keep a firmer lot for summer lines, include a warm-room burn in the qualification and write the reason for accepting it into your record.

Where this page fits

CSI already has guides that cover parts of this question. This page covers the goods-in check for the question above; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions