I Changed Jar Suppliers and Suddenly Developed Wet Spots — Should I Validate the New Container Before Changing My Wax Formulation?

Validate the new container first. Here is why, and how

When wet spots appear straight after a jar-supplier change, the change is the prime suspect by timing alone. Your wax, oil, load and wick were approved together in the old jar; the new jar is the only new ingredient. A jar change can alter adhesion in several ways commonly cited in candle making: different glass mass and wall thickness, a different internal shape or diameter, a different inner surface or residue, and — very often overlooked — a different set of limits that quietly changes your routine. If the new jar has a lower stated hot-pour limit than your usual pour temperature, you are no longer pouring the way you used to, even if nobody wrote that down.

That last point is worth an example, because it can happen with our own jar. CSI's Clear Glass Jar with Golden Lid (150 gram) page states "safe for hot pour up to 85°C". Luxury Soy Wax CSI 464's page gives an 80–90°C melt/pour working range. If your old routine poured CSI 464 at, say, 88°C into a jar with no such limit, moving to this jar means pouring at 85°C or below — a different glass-meets-wax moment, and one of the first things commonly cited for adhesion changes. Nothing about the wax changed; the routine did. In this jar, CSI 464 pours are limited to 80–85°C, and we say so plainly.

So the right order is a short container validation, with your old jar as the control at every step: does the new jar fit the candle; does the wax grip it, as received and cleaned; does your routine fit inside its limits; does it burn like the old one; does it survive your storage and courier route. Change the formula only if the new jar fails with the routine corrected and the glass cleaned — and even then, compare that cost with going back to the old jar. This page works the example with CSI 464 and Gardenia at 8% — 12 g of oil and 138 g of wax per 150 g candle.

Gate 1: does the new jar fit the candle?

Before any pour, measure. Weigh five empty jars of each kind. Fill one of each with water to your usual fill line and weigh it, then convert: solid soy wax is lighter than water, so a labelled approximate factor of about 0.86–0.90 g of wax per ml (it varies by wax, temperature and fill line) gives a first estimate, and one weighed test pour confirms it. CSI's Clear 150 g jar has a published fill of approximately 150 g — one of very few jars anywhere with a stated fill — so confirm that it matches the fill your recipe expects. If your old candle was 160 g and the new jar holds 150 g, the grams of oil per candle change with it, and so does your price per candle.

Then check the practical fit: does the lid close over your wick height; does your wick centring device sit on the new rim; does the label area match. These are not adhesion questions, but a jar that fails here wastes everything that follows. Measuring two jars of the same stated diameter gives a full measurement sheet — empty weight, inside diameter, rim wall, fill height — and explains how each figure can matter.

Gates 2 and 3: does the wax grip it, and does your routine fit it?

Pour three arms from one melt of your production wax lot: A — your old jar, as you always prepared it; B — the new jar, straight from its carton; C — the new jar after a controlled isopropyl-alcohol clean. All arms at one measured pour temperature that every jar allows. With CSI 464 in CSI's Clear 150 g jar, that means a reading inside the page's 80–90°C range and at or below the jar's stated 85°C — so the window is 80–85°C, and your old jar is poured at the same figure for this test. If you normally poured hotter, that is gate 3 being tested at the same time, deliberately: if the old jar also spots at the lower temperature, the routine change is your answer, not the glass.

Write the pass rule before pouring. A working rule you might adopt: the new jar passes gate 2 if arm B or arm C is no worse than arm A at 7 days and after the cycle — no more than one of its three jars grading above A's worst. If C passes and B does not, the new jar is fine and needs a cleaning step; cleaning jars commercially without residue sets that up. If A spots too at this pour temperature, the routine change explains your spots and the jar is innocent — whether a hotter pour is the answer and finding a temperature that gives adhesion and good tops are the next posts. Three jars per arm is a screen; pour three more of each before a final decision if the arms are close.

Gates 4 and 5: does it burn the same, and survive the route?

A jar that passes adhesion can still fail the candle. A different internal diameter or wall changes the melt pool and how hot the glass gets, so the wick approved in the old jar is a CONFIRM at best. Burn three new-jar candles beside three old-jar candles from one melt, with the same wick from the same pack, in cycles of about 3–4 hours with full cool-down between (a commonly used cycle — a labelled working practice). Record pool diameter and depth, time to full pool, flame height, soot and mushrooming, and how the glass feels. CSI publishes no wick size for any jar and no numeric flame-height or jar-temperature limit; acceptance is "no worse than the old jar on every safety line, and within the jar supplier's guidance". A hotter jar or a bigger flame is never traded for anything.

Gate 5 reuses the adhesion jars. Put them through a temperature cycle that matches your own storeroom or courier route — logged with a cheap min/max thermometer or data logger in a real parcel. An example cycle is 8 hours warm and 16 hours at room temperature, three to five times, with the warm phase well below CSI 468's stated 50–53°C melting point and never presented as a storage specification. Then photograph again. A new jar that grips on the bench and lets go after a week on the road has failed. A simple temperature-cycle test and repeated heating and cooling cover the method.

The priced validation kit

The example assumes the new jar is CSI's Clear 150 g jar and your production wax and oil are CSI 464 and Gardenia. The old jars are yours. Grams follow CSI's load convention (oil = W × L) with a 5% pour-loss working allowance.

The pack of 20 Clear 150 g jars is listed at ₹1,888.00 — the same ₹94.40 a jar — but in limited stock, so confirm on WhatsApp before planning a production order around it. The wick line is an example: CSI publishes no wick size for this jar, which is exactly why gate 4 exists.

Validation against reformulation: the money

At production rates — CSI 464 at the 5 kg rate, Gardenia at the 1 kg rate, the Clear 150 g jar at ₹94.40 and an Eco Thin C1 at ₹5.90 as the example wick line — a 150 g candle in the new jar costs ₹222.31 in materials. The two responses to spots after a jar change cost very different amounts before a single candle is sold:

The reformulation line is an example built on six SKUs, three adhesion and three burn jars each, and a three-jar control per pour day; your range will differ. It also costs more every month afterwards: CSI 468 is ₹637.00 a kilo at the 5 kg rate against ₹507.40 for CSI 464 — ₹17.88 more per 150 g candle. One SKU versus the whole collection and including development cost in a switching decision work through that arithmetic in depth.

The decision rule

Apply after each gate. Stop at the first line that is true.

Release the new jar formally: a short record of the gates passed, the jar supplier and delivery, the pour temperature now in use, the cleaning step, the wick confirmed and the date. Pour the first production batch with ten jars photographed at 7 days before the rest are shipped. Then keep the habit — a small production test for every supplier change — even when the next jar arrives with identical dimensions.

The CSI products in this validation

Where to go next

This post owns the validation of a new container. The glass-comparison post owns measuring and diagnosing two jars; the policy post owns making a small test standard for every supplier change; the thicker-glass post owns pour temperature in heavier jars; the shape post owns capacity-alike jars of different shape. The section hub covers the fragrance side if the jar is cleared.

Frequently asked questions