If you’ve ever noticed your candle wick forming a little mushroom-shaped tip after burning, you’re not alone! This is what candle makers call “mushrooming” — and while it’s a common issue, it can tell you a lot about your wick, wax, and fragrance balance.
Mushrooming happens when carbon builds up on the tip of the wick during burning.
It looks like a small black lump (like a tiny mushroom cap), and it can cause:
- A larger, flickering flame
- Soot or smoke
- Black marks on the jar
- Shorter burn times
It’s not usually dangerous — but it’s a sign that your candle isn’t burning as efficiently as it could.
Why Mushrooming Happens
There’s no single cause, but a few common factors can lead to that sooty buildup:
1. Wick Too Large
A wick that’s too thick draws up more wax than it can burn cleanly. The extra fuel leads to unburned carbon — aka mushrooming.
2. Too Much Fragrance Oil
Overloading your candle with fragrance can make the burn unbalanced. Fragrance oils are fuel, and too much of them can overwhelm the flame.
3. Improper Wax & Wick Match
Each wax type (soy, paraffin, coconut, etc.) behaves differently. The wrong wick for your wax blend may not burn efficiently.
4. Additives or Colour Load
Heavy dyes, mica powders, or certain additives can interfere with how cleanly your wick burns.
How to Fix or Prevent Mushrooming
1. Trim the Wick
Always start with a 5mm trimmed wick before lighting. Trimming between burns keeps the flame small and reduces carbon buildup.
2. Choose the Right Wick
If you’re testing a new formula, try a smaller wick size. For soy candles, wooden or eco-friendly cotton wicks often burn cleaner.
Tip: Use a wick testing kit to experiment with sizes and find the perfect fit for your jar and wax type.
3. Balance Your Fragrance Load
Stick to the recommended 6–10% fragrance oil load, depending on your wax type.
Too much scent not only causes mushrooming but can also lead to uneven tops or sweating.
4. Keep Burn Times Moderate
Avoid letting candles burn for more than 4 hours at a time. Overburning can lead to excessive carbon buildup.
When Mushrooming Is Normal
A small amount of mushrooming isn’t a problem — especially in heavily fragranced candles or certain wax blends.
If the wick is trimmed and the flame is steady, a tiny mushroom tip is excellent.
Mushrooming is one of those classic candle-making quirks that every maker encounters.
By testing your wick, managing your fragrance levels, and keeping good burn habits, you’ll enjoy cleaner burns and longer-lasting candles.
So next time you spot that little mushroom cap, think of it as your candle’s way of saying, “Hey, let’s fine-tune this formula!”