I Changed My Wax Blend from 90:10 to 80:20 — Is That Enough of a Formulation Change to Justify New Wick Testing?

How big is a move from 90:10 to 80:20?

A ratio change is two changes at once, and they are not the same size. The major component — the soy — falls from 90% to 80% of the wax, a relative drop of 11.1%. The minor component — the coconut wax — rises from 10% to 20%, a relative increase of 100%. In an 85 g tin at 8% fragrance there are 78.2 g of wax, so the coconut wax goes from 7.82 g to 15.64 g and the soy from 70.38 g to 62.56 g. If the reason the blend exists is what the minor wax brings to the candle, the change that matters is the one that doubled.

The table shows why "points moved" is a poor guide. A 95:5 → 90:10 change is only five points but also doubles the minor component. A 90:10 → 85:15 change is five points and a 50% increase. And 70:30 → 50:50 is twenty points, a 67% rise in the minor wax, and the major wax is now barely dominant. For change control, read a ratio change from the minor component's side: that is the side where the proportional change is biggest, and in most blends it is the component that was added for a reason.

So does it justify new wick testing?

Yes. Not a from-scratch wick search, but a wick bracket against the 90:10 control: your current wick and one alternative, burnt side by side at 80:20, three tins each, with every safety line scored. If the current wick is no worse than control on every line and the alternative is not better, the wick carries over — and you have evidence, not an assumption. If the lines move, the bracket has already shown you which way. The reason to test is not that CSI knows the new ratio behaves differently; we publish no burn, hardness or melt data for any of our waxes, and no data on blends. The reason is that nobody knows it behaves the same, and a doubled component is too big a change to assume.

The ratio-change protocol with tin counts

The protocol is a working practice, not a standard: three burn candles per variant, burn cycles of about 3–4 hours with full cool-down, cure checkpoints at 48 hours, 7 days and 14 days as labelled examples. Everything except the ratio stays fixed — same oil (Cinnamon at 8%, 6.8 g per tin), same tin, same fill, same wick placement. Because a single tin holds only 15.64 g of coconut wax at 80:20, make each ratio as a master batch: 800 g of Chunks with 200 g of Coconut Wax makes 1 kg of 80:20; 900 g with 100 g makes 90:10.

As everywhere in this series, the safety lines are judged against the approved control and against your container supplier's guidance and the fire-safety standard you work to — ASTM F2417 is commonly cited in the US. CSI publishes no numeric flame-height or container-temperature limit. If neither wick passes at 80:20, the answer may be that the new ratio needs a different wick family, or that 80:20 is not the right ratio for a tin — both are legitimate results.

The priced test kit and the cost of the new ratio

Everything below is a listed, in-stock CSI size, with a 5% pour-loss allowance (a working assumption). The tin's 85 g fill is published by CSI, so no weighed test pour is needed to confirm the candle weight — but do weigh one filled tin anyway to confirm your fill line matches.

Then the permanent cost change. Coconut Wax is listed at ₹1,026.60 a kilo against ₹599.00 for the Chunks, so doubling it raises the wax cost. In an 85 g tin the wax goes from ₹50.19 at 90:10 to ₹53.53 at 80:20 — ₹3.34 more per tin. In a 200 g candle at 8% the same change is ₹118.08 → ₹125.95, or ₹7.87 more. The payback post and the total-economics post show how to weigh a cost change like this against what the new ratio is meant to deliver.

Decision rule, release and the record

Record the new ratio as a master-batch recipe, not just a percentage: "1 kg blend = 800 g Luxury Soy Wax Chunks + 200 g Coconut Wax". Add the wick, the test-tin numbers, the storage readings and the sign-off. Keep the 90:10 card on file as the previous version, with its dates. Release in a small first batch, retain two tins as the new controls, and keep one burning to the end. If the ratio drifts again later, it is another change with its own test — and if the whole blend is being reconsidered, the soy-coconut post covers the switch itself.

Where ratio changes go wrong

The commonest failure is not a deliberate ratio change at all. It is a scoop-based blend that drifts from 90:10 towards 85:15 over a few months because nobody weighs the minor wax. By the time a batch misbehaves, nobody knows what ratio it was. Weigh both components, every batch, and record them. The second failure is changing the ratio and the load together because the new blend "should take more oil". That is two variables; the one-variable post explains why you would not know which one to blame.

The third is assuming a small tin needs less testing than a big jar. Tins are shallow and heat up as the wax gets low, so the end of life comes quickly and matters. The fourth is skipping storage because the change "is only the ratio". The minor component is often in the blend for its effect on the solid candle, so storage is exactly where a doubled dose shows. For the case where the minor component is a hardening addition rather than a second base wax, the harder-wax post runs a full dose ladder, and the master checklist lists every line for any wax change.

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