I'm Scaling from 1 Kg Test Batches to 25 Kg Commercial Batches — What Fragrance Formulation Variables Can Change Even When I Scale the Percentages Correctly?

The 25 kg arithmetic

Before looking at process, rule out the maths. CSI's convention, used throughout this series, sets load as a share of the finished candle: oil = total × load, wax = total − oil. Scaling that from 1 kg to 25 kg multiplies every number by 25. The trouble starts when a production sheet says "25 kg batch" and means 25 kg of wax. Then 8% of the wax gives a lower true load, and the batch is heavier than planned. I'm Making 10 Kg of Scented Candles at 8% Fragrance Load — How Do I Calculate the Exact Wax and Fragrance Quantities Without Accidentally Making a 10.8 Kg Batch? covers the same trap at 10 kg.

The formula for the last row is oil = wax × load ÷ (1 − load): 25,000 × 0.08 ÷ 0.92 = 2,173.91 g. Pick one convention, write it at the top of the batch sheet, and use the same one in test and production. If your 1 kg tests were made one way and production the other, you have changed the load by 0.59 points without meaning to — and that alone can make production smell weaker. I'm Making a 1 Kg Soy Wax Batch at 8% Fragrance Load — Do I Add 80 g Fragrance Oil to 1 Kg Wax or Should the 8% be Calculated from the Total Finished Candle Weight? sets out both conventions in full.

That is before the 3–5% extra we suggest planning for pour loss and test burns (a working assumption): 2,060–2,100 g of oil rather than exactly 2,000 g, which in practice means a third bottle or a 500 g on the shelf. Material cost per candle is ₹245.96, excluding labour, packaging, freight and GST. At this scale, a batch that has to be repoured or sold as seconds costs ₹30,744.90 in materials. That is the number the rest of this page is protecting.

The variables that do not scale

Each row below is a mechanism commonly described in candle-making practice, not a measurement from CSI. The point is not that every one will hurt your batch. It is that each one was effectively zero in a 1 kg pot, and none of them is zero at 25 kg. Your test batches approved the formula under conditions production cannot reproduce by default.

Two rows are worth quantifying. Weighing: at 1 kg, a 1 g error on 80 g of oil is 1.25% of the oil; at 25 kg the same 1 g is 0.05% — scale-up helps here, but only if you weigh the 2,000 g in one go. Weighing it as eight 250 g lots on a small scale, each 1 g heavy in the worst case, adds 8 g and moves the true load to 8.029%: negligible. The bigger risk is forgetting a lot. Heel: if 300 g of fragranced wax stays in the melter (an example — measure yours), that is 24 g of oil carried into the next batch. For the same scent that is simply yield; for a different scent it is contamination. I'm Making 10 Kg of Scented Wax at Once — How Do I Ensure Fragrance Oil Is Distributed Uniformly Throughout the Entire Batch? covers distributing oil uniformly through large batches.

Two melts, one batch

CSI lists two electric melters with published capacities: 10 kg at ₹21,240.00 and 20 kg at ₹25,960.00, plus a 1-litre mini melter at ₹2,360.00. Throughput in kilograms per hour is not published, and it is worth confirming whether the capacity refers to wax weight before planning around it. On the listed capacities, 25 kg is at least two melts. The cleanest plan is two equal 12.5 kg sub-batches, each fully weighed and fragranced on its own: 1,000 g oil + 11,500 g wax each.

Pilot at 5 kg first

Jumping from 1 kg to 25 kg changes every process variable at once, so if the result is off, you cannot tell which one moved. A 5 kg pilot sits in between: big enough that heat history, mixing and the pour window start to behave like production, small enough to lose without pain. At 8% it is 400 g oil and 4,600 g wax, 25 candles. With Apple Cinnamon and CSI 464, wicks and jars, the materials cost ₹6,148.98. Pour it with the production method, burn the first, middle and last jars against a 1 kg control, and fix what differs before the 25 kg run.

Buying for 25 kg batches

For production at this size, buy for lot control and continuity rather than price. CSI 464 is priced flat per kilo from 1 kg to 10 kg (₹507.40), so 10 kg bags cost the same per kilo as 1 kg bags but mean fewer lots. Apple Cinnamon is flat from 50 g to 1 kg. Oils with a real kilo saving are rarer — 24 in the catalogue show 5% or more — and Fallen Leaves is one that suits the same autumn and festive direction, at 10.0% below its 100 g per gram. Beyond the listed packs, larger quantities are quoted on WhatsApp; no discount figure is published.

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