If I Add More Wax to a Failed Scented Batch, How Do I Recalculate the Final Fragrance Percentage Accurately?

Why the recipe figure is no longer true

When a scented batch fails and you rework it, the obvious move is to reuse the original numbers: the recipe said 50 kg at 10%, so there must be 5,000 g of oil, so here is the wax to add. That calculation is tidy and slightly wrong, and on a large batch the error is big enough to matter.

Between the original pour and the remelt, scented wax goes missing. A film stays on every jar wall. Wicks and their tabs carry wax out with them. Some is spilled, some stays in the pitcher, some sticks to the melter. If the candles were sweating, some of the oil that rose to the surface may have been wiped off before recovery. None of that comes back to the pot.

So the batch you are diluting is not the batch you poured. Recalculating accurately means replacing every recipe figure with one you can weigh.

The accurate method, step by step

Here is the full sequence, worked on an example batch: 50 kg poured at 10% of total weight into 200 g jars, then recovered for rework. The target is 8%. Every figure below is an example; replace each with your own weighings.

Weigh the recovered wax melted and strained, not as broken plugs with wicks still in them; tabs, wick fibres and debris all add weight that is neither wax nor oil. If you must weigh solid pieces, remove every wick and tab first and accept that the figure is less precise.

The batch now weighs 59,200 g, which fills 59,200 ÷ 200 = 296 jars of 200 g — before any losses on the second pour. Order jars and wicks against that figure, not against the recipe's original count.

How much the shortcut gets wrong

Compare the accurate method with the tempting one that uses the recipe weight. Both target 8%.

Here the shortcut lands below target rather than above it, so it is not dangerous for sweating — but it is untraceable. The batch sheet claims 8%, the candles hold 7.91%, and any later comparison of throw or burn is made against a number that never existed. On a different batch, where much more wax stayed in the jars or the load was higher, the gap widens.

Which way the hidden errors push

Two losses cannot be weighed directly, and it matters that you know which way they push the result.

Wiped or drained oil. If sweated oil was wiped from the surfaces before recovery, the recovered wax holds slightly less than 10% oil. Your calculation, which assumes 10%, overstates the oil.

Heat loss on remelting. Holding fragranced wax hot can drive off some of the lighter materials in the oil. Nobody can give you that loss as a fixed figure without testing your oil in your process, and we will not invent one. It too means there is less oil than the calculation assumes.

Both errors run in the same direction: the true load is lower than the calculated load, never higher, provided no oil has been added. That is the right side to be wrong on when the original problem was sweating. It also means a reworked batch can throw a little less than its figure suggests — a reason to burn-test it, not a reason to add oil blindly.

If you collected the wiped oil

Some makers blot the sweated oil with tissue and could, in principle, estimate it by weighing the tissues before and after. If you did that, you can tighten the figure. Say the blotting removed an estimated 40 g. The oil left in the recovered wax is then about 4,730 − 40 = 4,690 g, and with 59,200 g in the pot the load is 4,690 ÷ 59,200 = 7.92%. Treat such an estimate as rough — tissue also absorbs a little wax — and record it as an estimate on the batch sheet.

If the recovery came from several pours

If the failed candles came from two or more original batches at different loads, do not average the percentages. Weigh each batch's recovered wax separately, calculate the oil in each, add the oils together, and divide by the combined weight after dilution. Two pots of 20,000 g at 10% and 15,000 g at 9% hold 2,000 + 1,350 = 3,350 g of oil in 35,000 g, which is 9.57% — not the 9.5% a simple average suggests.

Same wax, same lot, documented

Accuracy also means knowing what the added wax is. If the batch was Luxury Soy Wax Chunks, add Luxury Soy Wax Chunks. In this example the 11,825 g required is covered by a 10 kg pack plus a 5 kg pack: ₹5,999.00 + ₹2,995.00 = ₹8,994.00, leaving 3,175 g in stock. The cost of the wax actually used is 11,825 × ₹0.5999 = ₹7,093.82 at the 10 kg rate, excluding shipping and GST.

Chunks' product page states a maximum of 13% of wax weight. An 8% candle carries 16 g of oil in 184 g of wax — 8.70% of the wax — well within it. Remember that the stated maximum is a ceiling for typical oils, not a promise for yours; the reason you are diluting is that this pairing did not hold 10%.

Record the lot numbers of both the original wax and the added wax on the batch sheet. If the reworked candles behave differently from your pilot, you will want to know whether the added wax came from a different lot.

Verify with candles, not just numbers

A correct number is necessary and not sufficient. Pour a pilot from the diluted batch before the full run, cure it for at least the oil page's stated minimum, and check three things against a retained original: does it stay dry in storage and in your own supervised warm-room check, does the wick still burn cleanly at the new load, and is the hot throw acceptable. Never use a kitchen oven or anything near a flame for heat testing. If all three pass, pour the batch and file the worksheet with it. If the pilot still sweats at 7.99%, the oil and wax are not a good pair at any load you would want to sell, and the next decision is a different oil or wax.

Where this page fits

CSI already has guides that cover parts of this question. This page answers one sweating decision; these cover the neighbouring questions:

Three things to buy for this fix

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