My 1 Kg Batch Cools Quickly but My 20 Kg Wax Mass Stays Hot Much Longer — Can This Change Fragrance Addition and Finished Performance?

The failure: oil went in on the 1 kg clock

Your 1 kg method was simple: melt, switch off, wait about ten minutes, add oil, stir, pour. It worked every time because a kilogram of wax in a small vessel drops through its addition range quickly. The 20 kg batch — 18.4 kg of Premium Coconut Soy Wax CSI 468 and 1.6 kg of Neroli, a hundred 200 g jars, made in the 20 kg Electric Wax Melter — followed the same rhythm. The jars look fine. They smell thinner, as if the brightest part of the scent is missing.

The companion question is whether a large mass holding heat can change fragrance addition. This page starts after it already has. You need to know what temperature the oil actually met, for how long, and whether that explains the result — and you need to find out from records, because nobody put a thermometer in the wax at the time.

Reconstructing the temperature history from what you have

Gather every timestamped trace of the batch: the batch sheet, phone photos (they carry a time), messages you sent, and anyone who was there. Build a timeline of events first; temperatures come later.

Two facts are already visible without a single temperature. The oil went in ten minutes after the setting came down from the top, exactly as at 1 kg. And the scented wax then stayed in a heated melter for about an hour until the last jar was filled. What is missing is the one number that matters: the wax temperature at 10:15.

When the records are thin

Many makers find they wrote down the formula and nothing else. Even then, the day usually left traces: the time a helper arrived, the time the first carton was packed, a delivery that interrupted the pour. Put every one on the timeline, and mark each entry as recorded or estimated. An estimated time is still useful, but it widens the range you will read from the ghost run, and you should say so when you draw conclusions.

The ghost run: repeat the batch without the oil

You can recover that number by repeating the heating history with unscented wax. The unscented wax can go into your next batch, so the run costs time rather than materials.

Be careful with hot wax during the ghost run exactly as in production: this is 18.4 kg of liquid wax on an electrical appliance, so keep the area clear, keep the lid handy, and do not leave the melter unattended.

Reading what the reconstruction shows

Suppose the ghost run reads 91°C at 10:15. The oil met wax roughly six degrees above its published flashpoint, and well above the 58–60°C pour temperature CSI 468's page states. It then sat in heated wax for over an hour. That is enough to explain thinner, less bright jars without any fault in the oil or the formula. The small batch never saw anything like it: by the ten-minute mark, a kilogram had long since cooled into range.

If the ghost run instead shows the wax was already in your normal addition window at 10:15, heat at addition is cleared, and the long hold becomes the next suspect. Test that by making two 1 kg controls with correctly timed addition, pouring one at once and holding the other covered at pouring temperature for an hour before filling, then burning both coded beside retained production jars at equal cure age.

The production jars themselves carry a second clue. If the long hold mattered, jars poured at 10:25 and jars poured at 11:20 had different exposures to heat after the oil went in. Compare coded jars from the first and last part of the run at the same cure age. A clear step from first to last supports the hold as a contributor; no difference suggests the damage, if any, happened at the moment of addition, when every jar's oil was in the same hot wax.

What to do with the hundred jars

Hold them until the diagnosis is confirmed. Burn several at full cure, watching flame behaviour closely and extinguishing any that smoke or flare; oil added above its flashpoint does not necessarily make a candle unsafe to burn, but you should see the burn before selling it. If the throw is below what you sell, extra oil in a remelt is guesswork on heat-affected wax and adds another heat cycle. Downgrade, sell as clearly labelled seconds, or write off.

The cost of the mistake is worth writing down. The oil was 1.6 kg of Neroli bought as 1 kg at ₹6,655.20, 500 g at ₹3,327.60 and 100 g at ₹665.52 — ₹10,648.32. The wax was 18.4 kg of CSI 468 at ₹637.00 per kg (₹6,370.00 ÷ 10 kg) = ₹11,720.80. Together that is ₹22,369.12 of material, decided by a ten-minute habit.

Fixing the workflow, not the formula

The formula did nothing wrong, so leave it alone. Change the trigger for oil addition from a clock to a thermometer. Your ghost-run log now tells you how long this melter takes to bring 18.4 kg down to your addition window from its top setting; use that as a planning figure, but still add only when a mid-depth reading confirms it. For low-flashpoint oils like Neroli, keep a margin below the published figure.

Neroli is not the only oil where this matters. Among the oils in CSI's range, the product pages give Gardenia a flashpoint of 98°C and Royal Oud “above 93°C”. Keep a list of published flashpoints beside the melter, and for any oil whose figure is below 100°C, set your addition window with a clear margin under it. For oils with no published flashpoint on the page, ask CSI for the MSDS on WhatsApp before scenting a large batch.

Then shorten the time the scented wax spends in the heated melter: pour in smaller runs, or move scented wax into a pouring vessel so the melter's element is not working on the oil for an hour. Add three fields to the batch sheet — thermometer reading at addition, clock time at addition and clock time at last pour — so the next reconstruction, if one is ever needed, takes a glance rather than a day. For help reading your ghost-run log, message CSI on WhatsApp at +91 7397976926.

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