Candle Tunnelling

Candle tunnelling is the phenomenon of candles burning down in a tunnel around the wick, rather than burning down evenly across the entire top surface.

image source: reddit

Tunnelling occurs if, the very first time the candle was burned, it wasn't allowed to melt all the wax on top. This creates a "memory ring" in the wax. The candle will subsequently tunnel down this ring.

The solution, therefore, is to make sure the 'first burn' is done correctly. According to

Our biggest recommendation for the first burn, is to make sure that the pool of melted wax reaches the edges of your candle before you snuff the flame. We generally aim for the wax pool to be about 1cm deep at the edges before we put it out.
How long this takes depends on the diameter of the candle.

I realize now that I've been burning candles wrong my entire life.

I learned about this phenomenon via tywkiwdbi.
     Posted By: Alex - Thu Jun 25, 2020
     Category: Domestic | Interior Decorating | Weird Facts

My (late) parents retired to Lake Havasu City, AZ. There was a candlemaker's shoppe there, and they used "cores" of pure paraffin wax, with the outer bits something that burned at a hotter temperature. This is because the outer bits were differently colored layers which were twisted together, feathered, and otherwise used to create a pretty dust collector. When lit, the core burned down and left the outside deliberately.

Back in the 1970s, making your own candles in bottles using leftover wax or differently colored wax, then breaking the bottle was a thing. The "kit" sold a core with a wick already in it, running the length of the core. You guessed it, the core burned out, leaving the multi-colored wax behind. You could buy replacement cores to keep "your" creation functional, longer.

I'm afraid I'm skeptical of the claims of this wiki.
Posted by Mike Bird on 06/25/20 at 06:32 AM
You’ve been given some incorrect info. The cause of tunneling is incorrect wick size. A serious chandler does extensive testing to find the correct wick size (and type), based on the container, type of wax, and fragrance. All those things can affect how it burns. (So for instance, two candles that are exactly the same size and same container can still burn differently because of the fragrance used.)
The size and type of wick can also affect what is called the “hot throw”, which is how much scent the candle gives off when it’s burning.
Posted by Sharon on 06/25/20 at 08:31 AM
What Sharon said!

How well you keep the wick trimmed as it's burning makes a difference, too.

Most good commercial candles use the absolute minimum wick, so it's possible to get a complete burn, but it's far from guaranteed.
Posted by Phideaux on 06/25/20 at 09:49 AM
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