My Candle Hot Throw Became Weaker Immediately After Changing Wax Lots — Can Normal Wax-Batch Variation Affect Fragrance Performance?

Can a wax lot really change hot throw?

Short answer: it can, within limits. Soy wax is made from a crop, and each lot reflects the oil it was refined from and how it was processed. Small shifts in melt behaviour, hardness and the way the wax crystallises can change how freely fragrance moves out of the melt pool. A slightly firmer or higher-melting lot, for example, may give a smaller or slower melt pool with the same wick, and a smaller pool usually releases less scent.

What it cannot do is explain every weak candle that happens to follow a delivery. In the same week you may also have opened a new bottle of oil, poured at a different temperature because the room was cooler, shortened the cure to meet an order, or switched jars. Any of those changes can soften a hot throw on its own. The reason to treat this as a goods-in question is simple: once the new lot is in 135 finished candles, you can no longer separate the causes.

So the practical question is not whether batch variation is possible. It is whether this lot, in your formula, throws measurably weaker than the lot you had approved. That needs evidence you can repeat.

The paired test: one variable, eight candles

The companion question of whether wax, oil or wick is responsible belongs to a production investigation. Here the job is narrower: decide whether the lot on your shelf is fit to release. For that you need a paired test in which the only difference is the wax lot.

Four candles per lot is a suggested starting point to validate, not a standard. It gives you enough to see whether a difference repeats, without spending a week's oil on a single question.

Worked example: the cost of proving it

Suppose your bestseller is a 200 g lavender candle at 8% of total candle weight. Each candle takes 184 g of wax and 16 g of oil. Your new delivery is 25 kg of CSI 464, bought as two 10 kg packs and one 5 kg pack: 2 × ₹5,074.00 + ₹2,537.00 = ₹12,685.00. At 184 g per candle, 25 kg makes 25,000 ÷ 184 = 135 candles (rounded down).

The test costs about 11% of the wax alone (₹1,438.09 ÷ ₹12,685.00) and a small fraction of the oil you would pour into 135 candles if the throw really is weaker. The jars from the test are not wasted either: once judged, they can be kept as dated reference candles for the lot. If you normally buy lavender by the kilogram, the oil cost per gram falls, but the ratio between test and exposure stays much the same.

Judging the throw without fooling yourself

Hot throw is sensory, so the risk is bias rather than instruments. You already expect the new lot to be weaker, and that expectation will colour a sighted comparison. Reduce it with three habits.

First, code the bases so neither the pourer nor the judges know which candle is which until the scores are in. Second, use at least two people, and have each of them score independently before any discussion. Third, record simple, repeatable scores rather than adjectives: for example, a 1–5 intensity score at a fixed distance and a fixed time after lighting, plus a note on whether the character of the scent changed.

While the candles burn, record the melt pool too. If the new-lot candle reaches a smaller or slower full melt pool with the same wick, that is an objective observation you can hand to a supplier, and it points to a wax behaviour difference rather than a fragrance problem. If melt pools match but throw scores differ, repeat once before reading much into it.

Room conditions matter as much as the candles. A hot, well-ventilated room in the afternoon will make any candle seem weaker than the same candle in a still room at night. Burn the paired candles at the same time of day, with fans and air conditioning set the same way, and note the room temperature on the score sheet. If you have to burn on different days, alternate which lot goes first so that neither lot always gets the fresher nose.

Accept, conditionally release or reject

The goods-in decision follows from what the paired test shows. Record the outcome against the invoice and bag, whatever it is.

A conditional release is a legitimate outcome. It means the lot is approved for named uses, such as unscented pillars or a stronger oil that has headroom, with the restriction written on the bag label and in your records.

If the supplier is CSI, message WhatsApp +91 7397976926 with your invoice date, product, pack sizes, test method, scores and photos, and write down the answer. CSI product pages do not publish lot-specific data, so your own paired test is the evidence that matters. A lot that fails your comparison goes back in quarantine whoever supplied it, including us.

Where this page fits

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

Three things to buy for this job

Frequently asked questions