Candle Burn Testing: What to Record and Why It Matters

Why candle burn testing is the most important step you're probably skipping

If you sell candles, your customer isn't really buying wax and fragrance — they're buying a predictable burn. A candle that tunnels, smokes, or barely throws scent is a refund, a bad review, and a damaged brand. The single thing that separates hobby candle makers from professional candle businesses is rigorous, repeatable candle burn testing.

Burn testing (sometimes called a burn test or candle test burn) is the process of lighting a finished candle under controlled conditions and recording exactly how it performs over time. It tells you whether your wick size is right for your vessel, whether your fragrance load delivers a strong hot throw, and whether your pour temperature and cure time are actually producing a clean, safe burn.

This guide walks through a complete burn test checklist — exactly what to record during each candle burn test session, why each metric matters, and how Pour Logic's Burn Test Lab turns that data into better, more profitable candles.

The candle burn test checklist: what to record every session

A proper burn test isn't a one-off. Most candle makers run multiple burn sessions per candle (often 3–5), lighting the candle for around 4 hours at a time, letting it cool completely between burns, and logging what changes session to session. Here's the full checklist of what to capture — and every one of these fields is built into Pour Logic's Burn Test Lab.

1. Candle identity & test series

Before you light anything, record what you're testing so you can compare results later:

• Test series name — a label that groups related tests, e.g. "Lavender 8oz — CDN series".
• Burn session number — is this the 1st, 2nd, or 3rd burn? Early burns behave differently to later burns as the melt pool establishes.
• Linked candle recipe — tie every test back to the exact formulation (wax, fragrance, wick) so you can track which recipes perform best.
• Vessel diameter (mm) — wick choice is driven by container diameter. A wick that's perfect in a 70mm vessel will drown or tunnel in a 90mm one.
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2. Wick performance

Wick performance is the heart of candle burn testing. The wrong wick size is the #1 cause of poor candles. For each session, record:

• Wick type — CDN, HTP, wooden, ECO, LX, Premier — each series has its own burn characteristics.
• Wick size — e.g. CDN 10, HTP 70. Too small and you get tunneling and a weak melt pool; too large and you get smoking, soot, and a too-high flame.
• Flame behaviour — is the flame good, flickering, smoking, too high, or too low? A steady, teardrop-shaped flame is the goal.
• Mushrooming — carbon build-up on the wick tip (none / slight / moderate / severe). Heavy mushrooming signals a wick that's too big or a fragrance load that's too high.

When you find a wick that performs cleanly across all your burn sessions, you can mark it as "Recommended" in Pour Logic's Burn Test Lab — it then appears as a wick badge on the recipe card and feeds your wick comparison data.

3. Melt pool

The melt pool is the liquid pool of wax that forms around the wick as the candle burns. It's the single best indicator of whether your wick and vessel are matched correctly.

• Melt pool diameter (mm) — for a full, even burn, the melt pool should reach the edges of the vessel within a reasonable time (roughly 1 hour per inch of diameter). Measure at the widest point.
• Melt pool depth (mm) — ideal melt pool depth is around 6–12mm. Deeper pools run hot and burn through fragrance fast; shallower pools cause tunneling and wasted wax.
• Tunneling — none / slight / moderate / severe. Tunneling means the wick is too small or the candle wasn't burned long enough to establish a full melt pool.
• Burn duration (hours) — always record how long you burned the candle. Melt pool size only makes sense relative to burn time.

4. Scent throw (cold throw & hot throw)

Scent throw is what your customers actually notice. Cold throw is the fragrance from the unlit candle; hot throw is the fragrance released while burning — and hot throw is the one that makes or breaks a candle. Record scent throw on every burn session using a consistent scale:

• Very weak
• Weak
• Moderate
• Strong
• Very strong

Weak hot throw usually points to a fragrance load that's too low, a wick that's too small to melt enough scented wax, or fragrance that was added at the wrong temperature. Logging scent throw session-by-session helps you isolate whether the issue is the wick, the wax, or your fragrance-add temperature.

5. Soot & air quality

Soot is a quality and safety issue. A well-made candle should burn clean. Record soot level as none, minimal, moderate, or heavy. Heavy soot means your wick is too large, your fragrance load is too high, or the candle is being burned in a draft. Consistent soot across sessions is a red flag that needs fixing before you sell.

6. Vessel safety

Safety testing isn't optional for a candle making business. During each burn test, watch for:

• Glass temperature — the vessel should never get too hot to touch comfortably. If it does, your wick is too large or you have too many wicks for the vessel.
• Vessel integrity — no cracking or stress marks from heat.
• Flame height — a flame that's too high is a fire risk and a sign of over-wicking.
• Wick stability — the wick shouldn't drift, lean, or mushroom so badly it self-extinguishes.

Don't forget the environment — conditions change results

Two identical candles can test differently if one is poured at 60°C and the other at 75°C, or if one is burned in a humid room. That's why Pour Logic's Burn Test Lab lets you log the production and test environment alongside every session:

• Pour temperature (°C) — affects surface finish, adhesion, and cure.
• Fragrance add temperature (°C) — too hot and fragrance evaporates off; too cool and it won't bind to the wax, weakening hot throw.
• Room temperature (°C) and humidity (%) — both affect how a candle cures and burns.

When you mark a burn test as Recommended, Pour Logic automatically promotes those exact pour temperature, fragrance-add temperature, room temperature, and humidity figures onto the recipe as your production standard — so every batch you pour matches your best-performing test.

Turning burn test data into better candles

Recording data is only half the job. The real value of candle burn testing comes from comparing sessions and spotting patterns. Pour Logic's Burn Test Lab is built for exactly this:

• Wick Size Guide — data-driven wick recommendations per vessel diameter, so you're not guessing.
• Burn Sessions — every test is grouped by series and session number, so you can watch a candle's behaviour evolve burn-by-burn.
• Burn Test Results — a wick recommender that ranks wick/recipe combinations by performance, plus printable test reports for your quality control records.
• R&D Lab (Pro) — a success-score leaderboard that ranks your recipes by average R&D success score (1–100), a photo gallery of flame and melt pool test photos, and a reviewer breakdown for teams running multiple test sessions.

Over time, this builds a private database of candle performance — which wicks work in which vessels, which fragrance loads deliver the strongest hot throw, and which pour temperatures produce the cleanest burn. That's the difference between candle R&D and guesswork.

A simple burn test routine to start today

If you're new to structured burn testing, here's a minimal routine to build the habit:

1. Make a test candle and let it cure for at least 3 days.
2. Log the test series name, recipe, vessel diameter, wick type, and wick size in the Burn Test Lab.
3. Burn for 4 hours. Record burn duration, melt pool diameter and depth, flame behaviour, scent throw, soot level, and any tunneling or mushrooming.
4. Let the candle cool fully, then repeat for sessions 2, 3, and 4 — incrementing the burn session number each time.
5. Compare sessions. If the melt pool reaches the edge, the flame is steady, soot is minimal, and hot throw is strong, mark that wick as Recommended.

Do this for every new recipe or vessel before you sell it, and you'll catch issues in the lab — not in a customer's living room.

Start logging your burn tests properly

Candle burn testing is the difference between a candle that sells once and a candle that earns repeat customers. Pour Logic's Burn Test Lab gives you the structured checklist, the session tracking, the wick recommendations, and the R&D reporting to do it properly — all in one place, tied to your recipes and production standards.

Ready to stop guessing and start testing? Start your 7-day free trial of Pour Logic and log your first burn test session today.

Topics & keywords

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