The Ultimate Candle Making Guide

Whether you are pouring your first candle or refining a recipe for your hundredth, the glass container you choose shapes everything that follows — burn performance, scent throw, shelf appeal, and customer safety. At Coloured Bottles, we have supplied candle glass to makers of every scale for over 35 years, and in that time we have seen what works, what does not, and what separates a good candle from a truly excellent one.

This guide walks you through every stage of the process: choosing glass, selecting wax, sizing wicks, blending fragrance and colour, pouring, troubleshooting, and finishing for sale. Treat it as a reference you can return to whenever you need it.

1. Choosing the Right Glass Container

Glass is the most popular vessel for container candles, and for good reason. It is heat-resistant, non-porous, food-safe, infinitely recyclable, and it showcases the wax beautifully. But not all glass is created equal, and the shape and size you choose will affect burn pool formation, wick behaviour, and the overall look of your finished candle.

Heat Resistance

Always use glass designed for candle use. Standard drinking glasses and thin decorative vessels can crack or shatter when exposed to the sustained heat of a burning candle. Purpose-made candle glass is manufactured from soda-lime glass with walls thick enough to handle the thermal stress of a full burn cycle.

Size Guide

Container size determines burn time, wax volume, and the amount of fragrance released into a room. Here is a practical overview of common sizes:

Popular Shapes

The shape of the glass affects the burn pool and overall aesthetic. Straight-sided tumblers produce the most even burn pool because the flame does not need to work harder as the wax level drops. Tapered shapes like the conique add visual interest but may require a slightly different wick strategy.

100cl Deep Tub Candle Glass — View Product

Some of our most popular candle glass shapes include:

• Deep Tub — Classic straight-sided tumbler, produces an even burn pool. Available up to 100cl.
• Conique — Elegant tapered design, ideal for gifting and retail display. See the 10cl Conique.
• Travel — Compact and portable with a wide mouth. The 10cl Travel Glass is popular for sample sets and wedding favours.
• Beaker — Laboratory-inspired look with a pouring spout, trending in artisan and minimalist brands. See the 150ml Beaker Vessel.
• Large Format — For statement pieces and luxury candles, the 1kg Large Candle Glass offers impressive presence.

2. Selecting the Perfect Wax

Wax is the fuel that drives your candle. It determines burn time, scent throw, surface finish, and how the candle looks through clear glass. The five most common wax types for container candles are soy, paraffin, beeswax, coconut, and rapeseed — each with distinct characteristics.

Soy wax is the most popular choice for container candles. It burns slowly, adheres well to glass, and is marketed as a natural, renewable option. The main downside is frosting — a crystalline white bloom that can appear on the surface or sides of the candle, particularly in clear glass. This is purely cosmetic and does not affect burn performance.

Paraffin wax remains the industry standard for scent throw and colour vibrancy. It produces a glossy, smooth surface that looks exceptional through glass. The trade-off is that it is a petroleum by-product, which some consumers prefer to avoid.

Beeswax burns the longest of any natural wax and has a warm, golden colour with a subtle honey aroma. It is expensive and difficult to add fragrance to, but produces a beautiful, premium-feeling candle.

Coconut wax has surged in popularity in the luxury candle market. It offers excellent scent throw, a beautifully smooth finish, and a slow burn. It is typically blended with other waxes for structural stability.

Rapeseed wax is a European-grown alternative to soy that is gaining traction in the UK market. It offers good scent throw and a smooth finish, with strong environmental credentials due to short supply chains.

Many makers use wax blends — soy/coconut, soy/paraffin (parasoy), or coconut/rapeseed — to combine the best properties of each. For a deeper comparison, see our Candle Wax Types Explained guide.

3. Wick Selection and Sizing

The wick is the engine of your candle. Get it right and you will have an even burn pool, consistent scent throw, and a clean flame. Get it wrong and you face tunnelling, sooting, mushrooming, or — in the worst case — overheating the glass.

Why Wick Size Matters

The wick must be matched to the diameter of the container and the type of wax you are using. A wick that is too small will not create a full melt pool, leading to tunnelling (a ring of unmelted wax around the edge). A wick that is too large will burn too hot, produce soot, and potentially overheat the glass.

Wick Types

• Cotton-core wicks — The most common type for container candles. Flat-braided cotton wicks curl as they burn, which helps keep the flame centred and reduces mushrooming.
• Wood wicks — Produce a distinctive crackling sound and a wider, shorter flame. They create a broad melt pool quickly and add a sensory dimension. Require slightly different testing as the flame behaves differently.
• Zinc or paper-core wicks — Self-supporting wicks that stand rigidly upright, useful for containers where centring is difficult. Less commonly used in modern candle making.

Wick Sizing by Container Diameter

The Burn Test Protocol

Never skip testing. Make at least three test candles with different wick sizes and burn each for a minimum of four hours (or one hour per inch of container diameter). Record:

• Time to reach a full melt pool (edge to edge)
• Flame height (ideally 2–3 cm, no flickering)
• Soot production
• Glass temperature at the base (should remain comfortable to touch)
• Mushrooming on the wick tip

4. Adding Fragrance

Fragrance is what turns a plain candle into an experience. Understanding how fragrance interacts with wax — and with your glass container — is essential for consistent, high-quality results.

Fragrance Load

Fragrance load is the percentage of fragrance oil by weight of wax. Most candle waxes have a recommended maximum load:

• Soy wax: 6–10% (most manufacturers recommend 8–10%)
• Paraffin: 6–12% (can hold more fragrance than soy)
• Coconut wax: 6–10%
• Beeswax: 3–6% (lower capacity)

Exceeding the recommended load can cause the fragrance to leach out of the wax, creating wet spots on the glass or pooling on the surface.

Flash Point and Adding Temperature

Every fragrance oil has a flash point — the temperature at which it can ignite if exposed to an open flame. This is not the temperature at which you add it to wax. You should add fragrance oil when the wax has cooled to just above its pour temperature but is still liquid enough to mix thoroughly. As a general rule:

• Soy wax: add fragrance at around 55–60°C
• Paraffin: add at around 65–70°C
• Coconut blends: follow the manufacturer's recommendation, typically 55–60°C

Stir gently for at least two minutes to ensure even distribution.

Cold Throw vs Hot Throw

Cold throw is the scent released from an unlit candle. Hot throw is the scent released when burning. A candle can have a strong cold throw and a weak hot throw (or vice versa) depending on the wax type, fragrance quality, and wick selection. Paraffin and coconut waxes generally have the best hot throw, while soy excels at cold throw.

5. Adding Colour

Colour is particularly important when working with clear glass because the wax is fully visible. There are several options, each with different characteristics:

• Liquid candle dyes — The easiest to use. A few drops go a long way. They distribute evenly and produce consistent colour. Available in a wide range of shades.
• Dye blocks / dye chips — Concentrated solid dyes that you shave or chop into the melted wax. Good for strong, saturated colours. Easier to measure by weight for consistent batches.
• Mica powders — Produce a shimmering, metallic effect but do not dissolve in wax. Mica settles and can clog wicks, so it is best used only for decorating the surface of a finished candle, not mixed into the wax.
• Natural colourants — Turmeric, cinnamon, and dried botanicals can add subtle colour but may affect burn performance and are not recommended for beginners.

When using clear glass, remember that even a small amount of dye can produce a rich colour because you are seeing the entire depth of the wax. Test with half the amount you think you need, pour a small sample, and let it cool before committing to a full batch.

6. Pouring and Setting

Pouring technique directly affects the final appearance and performance of your candle. Getting the temperature right prevents a host of common problems.

Pour Temperatures by Wax Type

Single Pour vs Double Pour

A single pour is simpler and faster. For many soy and coconut wax formulations, a single pour at the correct temperature produces a perfectly smooth top. Double pouring involves filling the container about 90%, letting it cool and form a skin, then poking relief holes around the wick and topping up with a second pour. This technique prevents sinkholes — cavities that form beneath the surface as the wax contracts during cooling. Double pouring is particularly useful with paraffin and beeswax.

Cooling Environment

Pour your candles in a draught-free area at a stable room temperature (around 20–22°C). Avoid placing candles near windows, radiators, or air conditioning units while cooling. Uneven cooling causes wet spots (where the wax pulls away from the glass) and rough surfaces. Allow candles to cool slowly — do not put them in a fridge or freezer, as rapid cooling can cause cracking.

7. Troubleshooting Common Issues

Even experienced candle makers encounter problems. Here are the most common issues and how to fix them:

8. Finishing and Packaging

The final steps transform a hand-poured candle into a product that looks professional and is safe for sale.

Trimming Wicks

Trim wicks to approximately 5 mm before the first burn and before each subsequent burn. A trimmed wick produces a cleaner, more controlled flame with less soot. For cotton wicks, use sharp scissors or a dedicated wick trimmer. For wood wicks, break off the charred portion with your fingers.

Adding Lids

A lid protects the candle from dust, preserves the fragrance between uses, and adds a premium finish. It also makes the candle more suitable for gifting and retail display.

Silver Polished Candle Lid — View Product

Labelling and CLP Compliance

If you are selling candles in the UK or EU, your labels must comply with CLP (Classification, Labelling and Packaging) regulations. This means including:

• Product name and net weight
• Hazard pictograms (if the fragrance oil is classified as hazardous)
• Signal word (Warning or Danger)
• Hazard and precautionary statements
• Supplier name and contact details
• UFI (Unique Formula Identifier) if required

Consult your fragrance oil supplier's safety data sheets (SDS) for the specific classifications that apply to your products. CLP labelling is a legal requirement — not optional.

Packaging for Sale or Gift

For retail, consider branded boxes, tissue paper wrapping, or printed sleeves. For gift sets, pairing a candle with a complementary product (such as a matching smaller candle) in a presentation box adds perceived value. Include a care card with burning instructions to improve the customer experience and reduce complaints.

Frequently Asked Questions

What is the best glass container for a beginner candle maker?

A straight-sided tumbler in the 20cl–30cl range is the most forgiving choice for beginners. The even diameter makes wick sizing straightforward, and the moderate size keeps wax costs manageable while you experiment. Our deep tub range is available in multiple sizes and is a reliable starting point.

How long should I cure my candles before burning?

Curing — allowing the candle to rest after pouring — gives the fragrance oil time to bind fully with the wax. For soy wax, cure for at least one to two weeks. Paraffin candles can be burned after 48 hours, though a week is better. Coconut and rapeseed waxes benefit from at least one week of curing. The longer you cure, the better the scent throw.

Can I reuse glass containers for candle making?

Yes. Once the candle has burned down, clean out the remaining wax by pouring hot water into the container, letting it cool, and peeling off the solidified wax. Remove any wick adhesive with rubbing alcohol. Inspect the glass for cracks or chips before reusing — damaged glass should be recycled, not reused.

Why does my candle have wet spots on the glass?

Wet spots occur when the wax pulls away from the glass during cooling. This is a cosmetic issue — it does not affect burn performance. To reduce wet spots, pre-heat your glass to around 30–35°C before pouring, pour at the recommended temperature, and cool candles slowly in a draught-free environment.

How much fragrance oil should I use per candle?

A standard starting point is 8–10% of the wax weight for soy wax. For a 200 g candle, that means 16–20 g of fragrance oil. Paraffin can handle up to 12%. Always weigh your fragrance rather than measuring by volume for consistency.

Is it safe to use any glass jar for candle making?

No. Only use glass specifically designed for candle use or that has been tested for heat resistance. Thin glass, vintage jars, and drinking glasses can crack or shatter from the sustained heat. Purpose-made candle glass from a reputable supplier is always the safest option.

What causes a candle to tunnel?

Tunnelling happens when the melt pool does not reach the edges of the container, leaving a ring of unmelted wax. The most common cause is a wick that is too small for the container diameter. The first burn is critical — always burn your candle long enough for the melt pool to reach the edges on its first use (typically one hour per inch of diameter).

Do I need insurance to sell candles?

Yes. If you are selling candles commercially in the UK, you should have product liability insurance. Candles are a fire hazard, and proper insurance protects you if a product causes damage or injury. It is also a requirement for many retail stockists and craft fair organisers.

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