My Formula Passed 1 Kg and 5 Kg Tests — What Should I Specifically Evaluate When Moving to a 25 Kg Production Batch?

What your 1 kg and 5 kg batches have already proven

Be clear about what is already settled. The 1 kg test proved the recipe: CSI 468, Citrus Lemon, the wick and the jar work together at your chosen load. The 5 kg batch went further. It showed that your weighing arithmetic scales, that the oil blends into a few kilograms of wax, and that about 25 candles can be poured before anything drifts.

That is real progress, and it means the 25 kg evaluation can be narrow and sharp. You are not asking ‘is this a good candle?’. You are asking ‘does my process still make that candle when the batch is five times larger?’ Everything on your evaluation list should be something that 5 kg did not exercise.

It helps to name what 5 kg left open. It did not show how three separate melts compare with each other. It did not show what the last of 125 jars looks like when the wax has been in the pitcher and tank for much longer. It did not test whether your bench has room for five times as many jars to cool evenly, or whether the person pouring is still careful at the end of a long session. And it could not show what yield losses look like when residue in a deep tank and drips from many pitcher transfers are added up. Those gaps are the evaluation list.

The worked batch: CSI 468 with Citrus Lemon at 9%

Take a real formula. The maker uses CSI 468 with Citrus Lemon at 9% of total candle weight in 200 g jars. The Citrus Lemon page states a soy load of 6–10% and advises the upper end of the range, which is why 9% was approved at 1 kg.

One more calculation matters. If the melter's real working fill is about 8.5 kg — the page states 9.5 litres per melt, roughly 8.5 kg at about 0.9 g per ml — then 25 kg needs three fills. The 5 kg batch needed one. That single fact adds several of the new checks below.

The seven things only 25 kg can test

The acceptance figures in the last column are suggested starting points. Set your own, write them down before the batch, and judge the batch against them afterwards rather than deciding what ‘good enough’ means once you have seen the result.

Why hold time is the check to watch with citrus

Most oils tolerate a moderate hold without obvious change. Bright citrus is less forgiving. The Citrus Lemon product page itself warns that citrus top notes are volatile and fade faster than warmer families. In a 5 kg batch, the time from oil addition to the last candle was short. At 25 kg, even with fills scented separately, each fill may sit hot for considerably longer while jars are filled one pitcher at a time.

So measure it. For each fill, write the clock time at oil addition and at the last jar. Then burn a first-jar and a last-jar candle from the same fill side by side after the stated cure. If the last jar is flatter or less lemony than the first, and the control matches the first, hold time is your most likely cause.

Add oil below its published flashpoint and never with the melter at its maximum setting. No flashpoint for Citrus Lemon is quoted on this page, so ask for the oil's MSDS on WhatsApp, which CSI provides on request, and keep the addition temperature moderate in the meantime.

Sampling and the release decision

Pour a fresh 1 kg control on the same day: 910 g of CSI 468 and 90 g of Citrus Lemon. Number all 125 jars. From each fill, keep candles from the start and the end; as a suggested starting point, two burn-test candles and one unburnt retain per position per fill.

Cure everything together. The page asks for the full 48–72 hours for this oil; as a suggested starting point, test at day three and again at about one week. Burn positions beside the control in the same room, with the same draughts and the same timings. Stay with the candles throughout the burn and extinguish any that smoke or flare.

Release the 25 kg batch when every fill and every position matches the control, fill weights hold, and the yield reconciles. If one fill differs, release the others only if they are clearly traceable and clearly passed, and keep the odd fill back until you understand it.

What to change before the next 25 kg batch

Whatever the evaluation teaches, write it into the batch sheet as a fixed setting: the fill size you weighed, the oil split per fill, the maximum hold you observed without loss, the pour temperature band you actually achieved at the last jar. The next batch should inherit those numbers, not rediscover them.

And resist upgrades until the evidence asks for them. If the only problem was hold time, a second pitcher and a second pair of hands solve it more cheaply than new equipment. If fills differ because the melter display reads differently from your thermometer, the ₹354.00 pen thermometer used consistently fixes more than a bigger melter would.

Finally, treat the second 25 kg batch as a confirmation run rather than routine production. One passing batch shows the process can work; two in a row, made with the written settings, show that it repeats. Keep the same positional retains on the second batch, and move to lighter checks only once both have matched the control.

Where this page fits

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

Three things to buy for this job

Frequently asked questions