Candle Wick Selection: A Production Guide for Consistent Burn

The wick is the engine of a candle. An incorrectly sized wick causes tunneling, mushrooming, excessive soot, or a dangerously large flame. For B2B buyers working with OEM factories, understanding wick selection ensures your private-label candles burn consistently from first light to the last millimeter of wax.

Cotton Wicks vs Wood Wicks

Cotton Wicks

Cotton wicks dominate container candle production, accounting for roughly 85 percent of the market. They are available in flat-braid, square-braid, and cored (zinc or paper core) constructions.

• Flat-braid cotton: Self-trimming, curls as it burns to maintain an optimal flame height of 12-20mm. Best for soy and soy-blend waxes.
• Square-braid cotton: More rigid, handles higher viscosity waxes like beeswax blends. Resists drowning in deep melt pools.
• Cored wicks (zinc/paper): Provide structural rigidity for pillar candles and votives where the wick must remain upright without a sustainer tab. Zinc-core wicks are standard; paper-core offers a hotter burn for harder waxes.

Cotton wicks cost $0.02-$0.08 per unit depending on length and construction, making them economical for high-volume production.

Wood Wicks

Wood wicks (typically cherry, maple, or fruitwood) produce a crackling sound and a wide, low flame. They appeal to premium and lifestyle brands seeking a sensory differentiator.

Production considerations for wood wicks:

• They require wider containers (minimum 70mm diameter) to accommodate the broader flame footprint.
• Fragrance load must be reduced by 1-2 percent compared to cotton-wick equivalents, as the wider flame can scorch excess oil.
• Unit cost runs $0.15-$0.40 per wick, roughly 3-5x cotton.
• Burn time is approximately 15-20 percent shorter than equivalent cotton-wick candles due to faster wax consumption.
• Quality variance between wood wick suppliers is higher; buyers should specify moisture content below 8 percent and grain consistency in purchase orders.

Sizing by Container Diameter

Wick sizing is primarily determined by the container’s internal diameter and the wax type. The goal is a full melt pool (wax melted edge-to-edge) within 2-4 hours of burning, without the flame exceeding 25mm height.

General guidelines for soy wax in glass containers:

Container Diameter	Cotton Wick Size (flat-braid)	Wood Wick Width
50-60mm	CD 6-8 / ECO 4-6	Not recommended
65-75mm	CD 10-12 / ECO 8-10	10-12mm
80-90mm	CD 14-16 / ECO 12-14	13-15mm
95-110mm	CD 18-22 / ECO 14+ or double wick	16-20mm or double

For paraffin wax, size down by one increment due to its lower viscosity and faster melt rate. For beeswax or hard blends, size up by one increment.

Double-wicking is standard for containers exceeding 100mm diameter. The wicks should be positioned symmetrically, each offset from center by approximately 25 percent of the radius.

The Testing Protocol

Reputable OEM factories follow a structured wick testing protocol before production runs. Buyers should request documentation of this process:

Step 1: Initial selection. Based on container diameter and wax type, select three wick sizes (one below, one at, one above the estimated correct size).

Step 2: Test pour. Produce 3-5 units per wick size using production-grade wax and fragrance at the intended load percentage.

Step 3: First burn observation. Light candles and record:

• Time to full melt pool (target: 2-4 hours)
• Flame height at steady state (target: 12-25mm)
• Melt pool depth at 4 hours (target: 10-15mm, not exceeding 20mm)
• Soot production (visual assessment, zero visible black smoke)

Step 4: Full burn cycle. Burn candles through complete consumption, tracking:

• Total burn time
• Tunneling or residual wax on walls (acceptable: less than 2mm)
• Wick mushrooming frequency (acceptable: trimming needed no more than every 4 hours)
• Glass temperature at the hottest point (must not exceed 80 degrees Celsius for safety)

Step 5: Documentation. Record results in a burn test log with batch numbers, ambient temperature, and humidity. This becomes part of the product’s quality file.

Common Failures and Fixes

• Tunneling (wax remains on walls): Wick too small. Size up one increment.
• Mushrooming (carbon ball on wick tip): Fragrance load too high for wick capacity, or wick too large. Reduce load by 1 percent or size down.
• Drowning (flame extinguishes in melt pool): Wick too small for wax viscosity, or container too wide. Size up or switch to square-braid.
• Cracking glass: Flame too large, melt pool too deep. Size down immediately; this is a safety failure.

Specifying Wicks in Your Production Brief

When briefing your OEM factory, include:

• Container internal diameter (measured at the wax fill line, not the rim)
• Wax type and blend ratio
• Fragrance load percentage
• Target burn time
• Market destination (some retailers require specific wick certifications)
• Whether the wick must be lead-free certified (required for US market per CPSC 16 CFR 1500.17)

At Aromiso, every candle SKU undergoes a minimum three-size wick test before production approval. We provide burn test reports with each sample batch so buyers can verify performance before committing to volume orders.