I Bought a Large Wax Melter and Changed from 2 Kg to 20 Kg Batches — Should I Revalidate the Production Process Even Though Raw Materials Are Unchanged?

Why unchanged materials do not mean an unchanged process

The wax, fragrance, wick and jar are identical, so the recipe card is identical. What changes when a 2 kg batch becomes a 20 kg batch is everything the recipe card does not describe: how long the wax is held hot, how evenly a large volume is mixed, how the temperature moves while you pour, and how long the fragrance sits in hot wax before it reaches the last jar. At 5% loss (a working assumption), a 2 kg batch at 8% pours 9 candles of 200 g. A 20 kg batch pours 95. The pour window grows roughly in proportion to the candle count — about 10.6 times as many jars to fill — unless you add people, nozzles or jugs.

In general candle-making practice, each of those differences can show in the finished candles. A batch held hot for a long time with fragrance in it may not smell the same at the end of the pour as at the start. A large melter may have warmer and cooler zones, so candles poured from the top and the bottom are not identical. A batch that cools while you work through a hundred jars will be poured at a different temperature at the end, which can change the surface and adhesion. None of this is certain for your melter and your wax. That is exactly why it is revalidated rather than assumed.

The melters CSI lists, and what they do not tell you

CSI lists the Electric Wax Melter (Imported) in two capacities: 10 kg at ₹21,240.00 and 20 kg at ₹25,960.00 — ₹4,720.00 more for twice the listed capacity. There is also a Mini Electric Wax/Soap Melter, 1 litre at ₹2,360.00, with a one-year warranty, for small batches. What CSI does not publish is throughput — how many kilograms an hour either large melter melts — nor a working fill level, heat-up time or temperature uniformity. Any figure you plan with is yours, measured on your own first runs, or the manufacturer's manual; ask CSI on WhatsApp for the documentation that comes with the unit.

Listed capacity is not the same as the batch you should run. Many vessels are not designed to be filled to the brim, and a melter that is full to capacity may heat or stir less evenly than one run below it. Check the manual for the working fill, and if in doubt, validate at the batch size you will actually use — which may be 15 kg in a 20 kg melter. The protocol below is written for 20 kg of candle mix, the figure in the title; change it to your working fill.

The retest matrix for a batch scale-up

The protocol: one pilot batch, three pull points, one control

Run one full pilot batch at your working fill — 20,000 g of candle mix in this example: 18,400 g of CSI 464 and 1,600 g of Apple Cinnamon at 8%, pouring 95 candles of 200 g after a 5% loss allowance. On the same day, pour a normal 2 kg batch the old way (1,840 g wax, 160 g oil, 9 candles) and keep three as controls. From the pilot, pull three candles at each of three positions: the first candles poured, the middle of the pour and the last candles poured. Three per position is a labelled working practice. Hold every other pilot candle, labelled, until the test passes.

Scoring by pour position

Score each position against the 2 kg control, and against each other. CSI publishes no numeric flame-height or jar-temperature limit, so every safety line passes on "no worse than the control", within your jar supplier's guidance and the fire-safety standard you work to (ASTM F2417 is a commonly cited US example). The scale-up passes only if the last position passes; the first position passing proves very little.

Look at the first two rows together. If the last-position candles score lower on throw and were poured long after the fragrance went in, the hold time is the likely cause — test adding fragrance to jugs instead. If the temperature drifted out of the wax maker's range by the end of the pour, the surface lines will usually show it. The sheet is designed so that a failure points at a process fix, not a recipe change.

What the scale-up costs to validate

Wax and oil prices are CSI live pricing pulled 24 September 2026; the melters are from the same catalogue pull; jars and wicks are Blog 760's verified figures, with wick packs rechecked on 25 September 2026.

CSI 464 is flat at ₹507.40 a kilo in the 1, 5 and 10 kg bags, so the cheapest cover for 18,400 g is the mix that gets closest to it — 10 kg + 5 kg + 3 × 1 kg + 500 g at ₹9,393.20 — rather than 2 × 10 kg at ₹10,148.00; only the 500 g bag carries a premium (₹520.00 a kilo). Apple Cinnamon is ₹4.74 a gram at every size from 50 g to 1 kg, so the pilot's oil costs the same whichever bottles you choose.

Most of that is production stock, not test cost. The material in one 200 g candle is about ₹245.96 (wax and oil at the kilo rate, one White Matte jar, one Eco Thin C1 wick; excluding labour, packaging, freight and GST). The candles the test uses up — nine pilot pulls and three controls — are about ₹2,951.51. What is at risk is the other 86 pilot candles, about ₹21,152.49 of materials, held until the result is in. That is why the pilot is one batch, not a week's production.

The decision rule

None of the adjustments changes the recipe. If scale changes the candle, the fix is in the process — where and when fragrance goes in, how full the melter runs, how many people pour — and the pilot is rerun. Changing the fragrance load or the wick so that a 20 kg batch "comes out right" at the end of the pour makes the 2 kg candle and the 20 kg candle two different products. The significance checklist puts that kind of silent change in the revised-formulation tier.

Release and record

Scaling usually brings other changes with it — a mixer, more staff, a new pouring funnel — and each is a process change of its own. The mixing post covers the mixer; do it at your current batch size first, then scale. For a business moving to much larger volumes and several suppliers at once, the 1,000-to-10,000-candle post covers keeping formulation consistent as procurement grows, and the formula-record post shows how to make these new batch fields part of every record.

Frequently asked questions