Why do some candles have more than 1 wick?
As we saw previously, candles need to have the correct sized wick to prevent tunneling. However, it’s not always possible to find a wick that can burn efficiently and safely in a larger container. Multiple wicks are used when the container diameter is larger than 3 inches, which is about all 1 wick can handle without tunneling. We want the wax to melt all the way out to the sides of the container. This area of liquid wax is called a melt pool. Having a full melt pool that goes all the way to the edges of the container allows the candle to burn cleanly down the sides with no wasted wax. Also, the more the wax melts, the more the scent is released. We definitely want scent to be released!
PRO TIP: The first time you burn your candle, always let it stay lit until you have a full melt pool. Usually it takes about an hour for every inch of the container’s diameter, meaning a 3-inch candle should have a full melt pool in 3 hours or less. Candles burn in the same pattern each time, so this will avoid tunneling in the future.
Ever notice how some candles don’t smell like much when they are unlit but release a lot of fragrance once they are burning? The strength of the fragrance is called the scent throw and there are 2 types. Cold throw refers to how much scent is released when the candle is unlit and hot throw describes how much scent is released when the candle is lit.
Candles with multiple wicks will have a greater hot throw than those with only 1 wick, but that also means they use up the wax quicker, so they don’t last as long. Makes sense, right?
Candles typically burn 4-6 hours for every ounce of wax using 1 wick. There are lots of things that affect burn times, such as the size of the wick, number of wicks, amount of fragrance, and type of wax, but you can use this rate to estimate how long a candle should burn.
PRO TIP: Candle companies should provide estimated burn times to you, either on their labels or on their website. Use this info to see if you are getting the best value for your money!
To keep the math easy, let’s consider a 10-ounce candle. Based on the rate given above, this candle should burn for 40-60 hours if it has 1 wick. If it has multiple wicks, divide that range by 2 to estimate how long it should last. It’s not perfectly accurate, but it gives you a decent estimate.
Pro Tip: You shouldn't burn a candle for longer than 4 hours at a time. If you want to burn it longer, give it a rest first. Blow out the candle, let it cool until the melted wax begins to harden again, trim the wick, then relight it. You will get less carbon buildup on the wick this way, which results in better scent throw.
Bottom line is more wicks = shorter candle lifetime. This shows that there’s really no reason for smaller candles to have multiple wicks. They can burn efficiently with only 1, assuming that wick is the correct size. The advantages of multiple wicks are that the scent is released quicker and they tend to get full melt pools faster. They also look really pretty when they are burning!
Larger candles need to have multiple wicks to make sure they get full melt pools. However, there’s a limit to how many wicks you can fit into a container, even a bigger one! The wicks should be as evenly spaced as possible. If they are too close together, the melt pool gets deep very quickly and the wicks can shift or even fall over if not properly secured. If the wicks are placed too far apart and close to the sides of the container, the candle can burn unevenly and the wicks will leave black soot on the glass. And as we have seen, the glass could crack because it gets too hot.
Now that you know how important that wick really is, you can make better choices when buying your candles. Yes, the color and scent are what we are drawn to the most, but the best-smelling candle in the world won’t be worth the price if it is not wicked correctly.
PRO TIP: Don’t forget to think about the size of the room you want to fragrance with your candle. Larger spaces will require either a larger candle or several smaller candles. Get creative and burn several smaller candles that have complementary scents in different areas of a large room!
If you missed the background information on how wicks work, check out The World of Wicks - Part 1.