My Candle Looks Perfect at 25°C but Develops Wet Spots When Stored at 35°C — Why Does Temperature Change Affect Adhesion?
Share
Could it just look worse while warm? Yes. Score warm-stored jars in the store, then again after 24 hours back at 25°C. If the patches go, it is a viewing effect.
Should I change wax? Not first. Check the store's real temperature, the pour margin and the load. Test a second wax only after those.
What does the test cost? ₹0 with your own stock. From scratch, ten Yankee 130 ml jars with Chunks, Lavender, wicks and IPA come to ₹2,212.00. See the kit.
What the 35°C patches most likely are, and the first test
Start with what the patch is. A wet spot is commonly described as a thin air gap where wax has separated from the glass. Through clear glass it reads as a darker, glossier or mottled area, so it looks wet even though nothing is liquid. Your two readings — 25°C where the candle looks perfect, 35°C where it does not — are your figures, and they are the right starting point because they are measured in your own building rather than read off a weather app.
There are two quite different stories that fit the same observation. In the first, the warm store itself opens a gap: the wax and glass are commonly described as moving by different amounts as they warm, and a contact that was only just holding gives way somewhere on the wall. In the second, nothing permanent happens at 35°C, but the candle simply looks different while warm and you are judging it at the wrong moment — or the damage is done not by the heat but by the return to a cooler room. The fixes are different. The first points at pour margin, load and eventually wax. The second points at a storage and display rule and costs nothing.
So the cheapest first test is to separate "stored warm" from "seen warm" and from "warmed and cooled again". From one batch, keep three jars on your 25°C shelf, put three in your 35°C store and photograph them there, and put three more in the same store but bring them back to 25°C for a day before photographing. Keep a tenth jar as an untouched reference. The pattern across those arms tells you which story is yours before you spend anything on materials.
| Arm A · 25°C | Arm B · 35°C, scored warm | Arm C · 35°C, back to 25°C | What it points to |
|---|---|---|---|
| Clean | Spotted | Clean again | A warm-viewing effect — set a storage and display rule |
| Clean | Spotted | Still spotted | Warm storage opened a real gap — work the pour margin, then load |
| Clean | Clean | Spotted | The return to cooler air is the trigger — see the AC-to-summer post |
| Spotted | Spotted | Spotted | Not storage temperature — the pour or cure, see late-appearing patches |
| Mixed in every arm | Mixed | Mixed | Jar-to-jar variation is bigger than the temperature effect — more jars, record batch position |
Why a ten-degree difference can matter to wax on glass
In general candle-making practice, soy wax is described as contracting as it cools and crystallises after the pour, and as continuing to settle for days. The glass does not move in step with it. While the wax is still in full contact with the wall, the jar looks clear and even. Where the contact is weak — a slightly cold patch of glass on pour day, a fingerprint, the side that faced a draught — a later stress can complete the separation and a patch appears. Warming a set candle from 25°C to 35°C is that kind of stress. It is commonly described as softening the wax a little and making the wax and glass expand by different amounts; when the candle cools again, they contract by different amounts. We publish no expansion coefficient, contraction percentage or adhesion figure for any CSI wax or jar, so this page does not attach a number to that mechanism. It measures your candle instead.
Two points follow from the mechanism. First, a warm store is rarely a steady 35°C. A storeroom under a roof can climb through the afternoon and fall at night, so a candle "stored at 35°C" may actually be cycling every day — which is the repeated-cycle question rather than a storage question. Log the store with a min/max thermometer for a week before you assume it is steady. Second, the size of the jar wall you can see matters to how visible any patch is. A small clear jar such as the Yankee 130 ml shows its whole wall at a glance, so a patch that would hide behind a label on a larger jar is the first thing a customer notices.
The Chunks page states a maximum fragrance load of 13%, fragrance addition at 80–90°C and a pour of 75–80°C in its spec table (the page's step list also shows 70–80°C). It also says the wax has "excellent adhesion to glass and container surfaces". The CSI 464 and CSI 468 pages make the same adhesion claim, so that sentence cannot tell you which of them copes better with a warm store. Treat it as a claim to test in your own jar at your own temperatures, as you would any supplier's description.
The storage-temperature ladder, cheapest rung first
The full series ladder runs from "is it really a wet spot?" through glass cleanliness, glass and pour temperature, cooling, storage and courier cycling, fragrance and dye, jar glass and finally the wax. For a candle that is perfect at 25°C, the pour-day rungs have partly cleared themselves: something about the pour was good enough to give a clean wall in your normal room. But a pour can be good enough at 25°C and only just good enough, which is why rung 3 below goes back to the pour before any material changes.
| Rung | Suspect | Single test | What it costs you |
|---|---|---|---|
| 1 | Is the 35°C store really steady? | Min/max thermometer in the store for 7 days; note the daily high and low | A thermometer (non-CSI; your quote) |
| 2 | Warm look or real gap? | Arms B and C: score warm, then score after 24 hours back at 25°C | Nothing beyond the jars |
| 3 | Is the pour marginal? | Repeat arm C with jars poured on clean, room-temperature glass and cooled away from draughts | One more batch |
| 4 | Is it the load? | Same arms at 6% and 8% (Chunks allows up to 13% on its page) | Wax + oil, see the load table |
| 5 | Is it this oil? | Unscented jars beside scented jars through the same 35°C store | Wax only |
| 6 | Is it the wax–jar pairing? | A second CSI container wax through the same arms, same jar, oil and load | One 500 g or 1 kg bag |
Rung 3 is where most warm-store problems end. A pour on glass that was cooler than the room, or candles that set beside an open window, can look perfect at 25°C and give way at 35°C, while the same wax poured with a little more care does not. Cooling under the AC and the AC-vent post cover the two cooling conditions that most often make a pour marginal, and the winter-glass hub covers glass preparation. If rung 3 clears it, the fix is a written pour-day step, not a purchase.
The three-arm storage test
The worked example uses CSI's Yankee Glass Jar 130 ml. Its fill weight is not published — 130 ml is the brim volume. Solid wax is lighter than water: with a labelled approximate conversion of about 0.86–0.90 g of wax per ml, the brim volume would hold roughly 111.8 g–117.0 g, and a sensible fill line sits below the brim. This page uses an example fill of 100 g; weigh your own test pour and replace it. At 8% that is 8 g of oil and 92 g of wax per jar. The example wax is Luxury Soy Wax Chunks poured inside its page's 75–80°C spec-table range, with Lavender as the oil. CSI does not publish a hot-pour limit for the Yankee jar, so follow the jar supplier's guidance and ask us on WhatsApp if you need it confirmed.
| Checkpoint | Arm A · 25°C | Arm B · 35°C | Arm C · 35°C then 25°C | Jar 10 |
|---|---|---|---|---|
| Pour day | Photo | Photo | Photo | Photo |
| 48 hours | Photo + score | Photo + score | Photo + score | Photo |
| 7 days, all at 25°C | Photo + score | Into the store | Into the store | Photo |
| After 7 days stored (example) | Photo + score | Photo + score in the store | Back to 25°C | Photo |
| +24 hours | — | — | Photo + score | — |
| 30 days | Photo + score | Photo + score after 24 h at 25°C | Photo + score | Photo + score |
Three jars per arm is a screen. It will show a clear, consistent difference — all three warm-stored jars spotted, none at 25°C — but not a subtle one. If the screen is ambiguous, add jars to the two arms that differ rather than adding new conditions. In this example each extra jar costs about ₹182.90 in CSI materials (the kit's materials ÷ 10 jars). Testing across several temperatures before pan-India approval shows how to grow this into a launch matrix once you know which temperatures matter.
Load and oil: the rungs before the wax
Fragrance oil changes how wax sets — this is commonly described in candle-making practice, and makers often report that the same wax adheres differently with different oils or at different loads. CSI publishes no adhesion data for any oil and we will not suggest that lavender, or any other oil, is better or worse. What you can do cheaply is test the load you actually use against a lower one, and a scented candle against an unscented one, through the same warm store. The table shows what each load costs per candle at production rates in the example 100 g fill.
| Load | Oil per candle | Wax per candle | Oil cost | Wax cost |
|---|---|---|---|---|
| 6% | 6 g | 94 g | ₹31.33 | ₹56.31 |
| 8% | 8 g | 92 g | ₹41.77 | ₹55.11 |
| 10% | 10 g | 90 g | ₹52.21 | ₹53.91 |
Read the table as a test plan, not a recommendation. If 6% jars survive the warm store and 8% jars do not, you have learned something useful — and you then need a throw check at 6% before you change production, because a candle that looks perfect and smells of nothing is not a fix. The 6% versus 10% post runs that load ladder in full, and the scented-versus-unscented hub covers the oil-by-oil comparison. A wax change is the last rung precisely because it re-opens wick, load, cure and throw validation all at once.
The scoring sheet, with the temperature written on it
Use one house scale for every jar at every checkpoint. The example below is a 0–4 grade estimated through the glass, with an optional percentage estimated using a printed grid or a marked acetate sleeve wrapped round the jar. It is an example of a house standard — no industry figure for an acceptable wet spot exists. Add the one column most sheets leave out: the temperature the jar was at when it was scored.
| Jar | Arm | Scored at (°C, your reading) | Hours at that temperature | 12 | 3 | 6 | 9 | Grade 0–4 | Notes |
|---|---|---|---|---|---|---|---|---|---|
| 1 | A · 25°C | ___ | ___ | ___ | ___ | ___ | ___ | ___ | Batch position ___ |
| 4 | B · 35°C warm | ___ | ___ | ___ | ___ | ___ | ___ | ___ | Store high/low ___ |
| 7 | C · 35°C then 25°C | ___ | ___ | ___ | ___ | ___ | ___ | ___ | Grade warm ___ / after 24 h ___ |
| 10 | Reference | ___ | ___ | ___ | ___ | ___ | ___ | ___ | Never moved |
Decide your pass line before the first score — for example, "no jar in arm C above grade 1 after 24 hours back at 25°C". That is a house choice; how much variation is normal helps you defend it. Then decide what the arm B scores are for. If you only ever sell from a cool room, a warm-viewing effect may not matter to you; if your stock sits in a 35°C shop window, it is exactly what the customer sees.
The priced test kit
If you already make this candle, rungs 1–3 need nothing from us: use your own jars, wax, oil and wick from the same lots. From scratch, here is the ten-jar kit priced with listed, in-stock CSI packs, using the CSI convention (oil = W × L) and a 5% pour-loss working allowance: 10 jars × 92 g wax = 920 g, plus 5% = 966.0 g; 10 × 8 g oil = 80 g, plus 5% = 84.0 g.
| Item | Need | Buy | Price | Skip if |
|---|---|---|---|---|
| Yankee 130 ml jar | 10 jars | 10 × pack of 1 | ₹472.00 | You already hold this exact jar from one lot |
| Luxury Soy Wax Chunks | 966.0 g | 1 × 1 kg | ₹599.00 | You hold enough wax from your current lot (better) |
| Lavender | 84.0 g | 1 × 100 g | ₹540.00 | You test your own production oil (better) |
| Eco Candle Wicks Thin C1 | 10 + 2 spare | 1 × pack of 20 (10-pack out of stock) | ₹118.00 | You use your own approved wick (you should) |
| Wick stickers | 10 | 1 × sheet of 40 | ₹100.00 | You hold stickers |
| Isopropyl Alcohol Spray | Jar wipe for every jar | 1 × 150 ml | ₹383.00 | You already clean jars with a residue-free method |
| Kit total, everything bought | ₹2,212.00 |
That is ₹182.90 of CSI materials per test jar before the IPA spray. Leftovers: 34 g of wax, 16 g of oil and 8 wicks. Note the oil line: the 100 g bottle at ₹540.00 costs the same per gram as two 50 g bottles, and the 15 g size is dearer per gram (₹7.00 against ₹5.40) — for 84.0 g the 100 g is simply the cheapest way to cover the need. The Eco Thin C1 line is the example wick only: CSI publishes no wick size for this jar, so burn-test any wick before you rely on it. Your thermometer for the store is a non-CSI item.
What warm-store spots cost you
Before deciding how far up the ladder to go, put a number on the problem. The material cost of this example candle at production rates is ₹55.11 of Chunks (at the 5 kg rate) + ₹41.77 of Lavender (at the 1 kg rate) + ₹5.90 example wick + ₹47.20 jar = ₹149.98, excluding labour, packaging, freight and GST. Everything else in the table is a labelled example: replace the stock count, spotted share, selling price, discount and label cost with your own.
| Line | Example | Working |
|---|---|---|
| Candles held in the warm store | 200 | Your count |
| CSI materials in that stock | ₹29,995.20 | 200 × ₹149.98 |
| Share spotted after the warm months | 25% | From your arm C result, not a guess |
| Spotted candles | 50 | 200 × 25% |
| Treatment 1 · sold at a discount | 30% off ₹499.00 | Your price and discount |
| Revenue given away | ₹7,485.00 | 50 × ₹499.00 × 30% |
| Spread over the full-price candles | ₹49.90 | ₹7,485.00 ÷ 150 |
| Treatment 2 · hidden behind a wrap-around label | ₹12.00 each | Your printer's quote |
| Label cost | ₹600.00 | 50 × ₹12.00 |
| Materials per full-price candle | ₹199.97 | ₹29,995.20 ÷ 150 |
Keep the two treatments separate; adding them double-counts. In this example, discounting gives away ₹7,485.00 on one stockroom's worth of candles, while labelling costs ₹600.00 and changes the look of the product you designed around clear glass. Either figure is the budget a fix has to beat. A storage rule costs close to nothing; a second ten-jar test round costs about ₹1,829.00 in CSI materials; a wax change costs a full revalidation. The discounted-stock post and the opaque-label post take each treatment further.
The decision rule
Apply it from the top after the 30-day checkpoint and stop at the first line that is true.
| If this is true | It means | Do or buy |
|---|---|---|
| Arm A spots as much as B and C | Not storage temperature | Nothing new. Work the pour-day rungs (the process-diagnosis capstone) |
| B spots warm, C recovers fully after 24 h | A warm-viewing effect | Nothing. Write a storage and display rule: below your tested temperature |
| C keeps spots; a careful-pour C does not | The pour was marginal | Nothing. Write the better glass prep and cooling into your SOP |
| Careful pour still fails; 6% passes, 8% fails | Load is part of it | Throw-check 6% before switching production |
| Unscented passes, scented fails at every load | This oil in this wax | Test the oil in a second wax before changing your whole range (one-oil post) |
| A second wax passes on two rounds; first wax fails | The wax–jar pairing | One 5 kg bag of the passing wax, then wick and throw retests |
| Nothing passes at 35°C | Clear glass and a 35°C store do not mix for this SKU | Store cooler, or consider a frosted jar (the frosted-jar post) |
Most outcomes end in a rule rather than a purchase. That is the honest shape of this problem: a candle that is perfect at 25°C has already shown it can adhere. If Chunks is the wax you keep or move to at production volume, compute the pack before you order — the 10 kg bag is ₹5,999.00, which is ₹599.90 a kilo, while two 5 kg bags at ₹2,995.00 each are ₹599.00 a kilo and ₹9.00 cheaper in total. There is no volume discount on the listed packs; anything larger is quoted on WhatsApp.
The CSI products in this test
| Pack | Price | Per jar |
|---|---|---|
| 1 jar | ₹47.20 | ₹47.20 |
| Pack | Price | Per kg | Candles at 92.0 g wax |
|---|---|---|---|
| 500 g | ₹299.00 | ₹598.00 | 5.4 |
| 1 kg | ₹599.00 | ₹599.00 | 10.9 |
| 5 kg | ₹2,995.00 | ₹599.00 | 54.3 |
| 10 kg | ₹5,999.00 | ₹599.90 | 108.7 |
| Pack | Price | Per gram | Candles at 8.0 g |
|---|---|---|---|
| 15 g | ₹105.02 | ₹7.00 | 1.9 |
| 50 g | ₹270.00 | ₹5.40 | 6.2 |
| 100 g | ₹540.00 | ₹5.40 | 12.5 |
| 500 g | ₹2,620.00 | ₹5.24 | 62.5 |
| 1 kg | ₹5,221.00 | ₹5.22 | 125.0 |
CANDLEMAKINGSUPPLIESINDIA supplies raw materials, not finished candles. A wax seller's easy answer to warm-weather spots is a new wax. This page says that our three container soy waxes' pages all make the same adhesion claim, that we publish no warm-storage results for any of them, and that the most likely fix is a storage rule that costs nothing.
Oil prices are CSI live pricing, pulled 24 September 2026, stock re-checked 7 October 2026. Luxury Soy Wax Chunks, CSI 464 and CSI 468 are CSI live pricing, re-checked 7 October 2026; Natural Soy Pearl was re-checked 1 October 2026. Jar and Isopropyl Alcohol Spray prices are CSI live pricing, pulled 7 October 2026; wick prices are re-checked 4 October 2026, including the Eco Thin C1 10-pack being out of stock. Every gram split, per-jar figure and kit total on this page is computed and shown to two decimals so you can check it.
Jar counts per arm, photo checkpoints, temperature-cycle settings, storage temperatures you have not measured yourself, the scoring scale and the pour-loss allowance are labelled working practices or example settings, not industry standards — none exists for wet spots. The 100 g fill for the Yankee 130 ml jar is an example — its fill is not published. The stockroom count (200), spotted share (25%), selling price (₹499.00), discount (30%) and label cost (₹12.00) are examples you replace. For help building a test kit, bulk quotes, GST invoicing, MSDS or IFRA documents, message us on WhatsApp at +91 7397976926.
Frequently asked questions
- My Candles Have Perfect Glass Adhesion in My Workshop but Develop Wet Spots After Courier Delivery — Are Temperature Cycles Causing the Wax to Separate from the Glass?
- My Candle Develops New Wet Spots After Moving from an Air-Conditioned Room into Indian Summer Heat — Is Wax Expansion and Contraction Responsible?
- Can Repeated Heating and Cooling During Ecommerce Delivery Make Glass Adhesion Progressively Worse?
- Should I Test Candle Glass Adhesion Across Multiple Temperatures Before Approving a Formula for Pan-India Shipping?
- How Do I Create a Simple Temperature-Cycle Test for Clear-Glass Candles Intended for Indian Ecommerce?
- My Candles Cool Directly Under an Air Conditioner and Develop Patchy Adhesion — Could Rapid Cooling Be Responsible?
- My Candle Has Good Adhesion at 6% Fragrance but Becomes Patchy at 10% — Should I Optimise Fragrance Load Before Replacing the Wax?
- Should I Choose a Frosted Jar Instead of Changing My Entire Wax Formula if the Candle Performs Beautifully but Has Minor Adhesion Variation?
Customer reviews: The six reviews at the top of this page are genuine, published Judge.me reviews left by CSI customers on the product pages named on each card — Eco Candle Wicks, Premium Candle Wicking Needle and Bamboo Wick Holder. They are general product reviews, not assessments of the guidance set out here. Names, star ratings, dates and products are as recorded by Judge.me and wording is unedited. "Verified buyer" appears only on the three reviews Judge.me recorded as verified — Monika Deep, Subhankar Roy and Sneha Tamang; the reviews from Ashwini, LJ and Lalitha Jagan are published but not recorded as verified, and carry no badge.
Figures pulled 24 September – 7 October 2026: Oils — CSI live pricing, pulled 24 September 2026, stock re-checked 7 October 2026: Lavender Fragrance Oil ₹105.02 / 15 g, ₹270.00 / 50 g, ₹540.00 / 100 g, ₹2,620.00 / 500 g, ₹5,221.00 / 1 kg. Waxes — Luxury Soy Wax Chunks (CSI live pricing, re-checked 7 October 2026) ₹299.00 / 500 g, ₹599.00 / 1 kg, ₹2,995.00 / 5 kg, ₹5,999.00 / 10 kg; Luxury Soy Wax CSI 464 (CSI live pricing, re-checked 7 October 2026) ₹260.00 / 500 g, ₹507.40 / 1 kg, ₹2,537.00 / 5 kg, ₹5,074.00 / 10 kg; Premium Coconut Soy Wax CSI 468 (CSI live pricing, re-checked 7 October 2026) ₹325.00 / 500 g, ₹650.00 / 1 kg, ₹3,185.00 / 5 kg, ₹6,370.00 / 10 kg. Jars and accessories — CSI live pricing, pulled 7 October 2026: Yankee Glass Jar 130 ml with clear cap ₹47.20 / 1; Isopropyl Alcohol Spray ₹383.00 / 150 ml, ₹520.00 / 1 litre. Wicks re-checked 4 October 2026: Eco Candle Wicks Thin C1 ₹118.00 / 20, ₹295.00 / 50, ₹590.00 / 100 (10-pack out of stock); Eco Thick C2 ₹94.40 / 10, ₹188.80 / 20; wick stickers ₹100.00 / 40. Pen Thermometer ₹354.00; Candle Making Weighing Scale ₹354.00.
Non-price figures and assumptions: Load convention: fragrance load is a share of the finished candle (oil = W × L; wax = W × (1 − L)). Reader's figures: 25°C and 35°C. Yankee 130 ml jar: fill not published; brim 130 ml × a labelled approximate 0.86–0.90 g/ml = 111.8 g–117.0 g; example fill 100 g at 8% = 8 g oil + 92 g wax — weigh your own. Working practices: 3 jars per arm plus 1 reference, 5% pour loss, example 7-day store period, scoring warm and after 24 hours at 25°C, 30-day checkpoint, 0–4 house scale. Per-candle cost uses the Chunks 5 kg rate and the Lavender 1 kg rate. Example stockroom figures are placeholders. What CSI's product pages state (quoted, not CSI test results): Luxury Soy Wax Chunks — maximum fragrance load 13%, fragrance addition 80–90°C, pour 75–80°C in the spec table (the step list also shows 70–80°C), stir 2 minutes, cure at least 48 hours, ideally 1–2 weeks, and "excellent adhesion to glass and container surfaces"; Luxury Soy Wax CSI 464 — fragrance load up to 10%, an 80–90°C melt/pour range, "excellent glass adhesion", single-pour, low frosting; Premium Coconut Soy Wax CSI 468 — melting point 50–53°C, pour 58–60°C, fragrance load up to 13%, "formulated for excellent glass adhesion"; Natural Soy Pearl — no fragrance ceiling, temperature, cure or adhesion statement published. Clear Glass Jar with Golden Lid (150 gram) — fill approximately 150 g, "safe for hot pour up to 85°C". All three adhesion statements are the same claim, so they cannot rank the waxes; only a side-by-side test in your jar can. CSI publishes no adhesion, wet-spot, contraction or shrinkage data for any wax, oil, dye or jar, no glass thickness or internal diameter for any jar, no wick size for any jar, and no heat-survival or temperature-cycle results. There is no industry acceptance threshold for wet spots; every scale and pass line on this page is a labelled house standard. Wet-spot mechanisms are described as general candle-making knowledge. Material costs exclude labour, packaging, freight and GST. Diwali 2026 falls on Sunday 8 November.