Candle making looks simple, but wick sizing is a real, somewhat technical matching problem, and the wax-heating step carries a genuine fire risk that's easy to underestimate.
Wick size has to match wax type and container diameter
A wick that's too small for a candle's diameter burns with a small flame that doesn't create a wide enough melt pool, causing the candle to tunnel down the middle and leave wax unused along the sides. A wick too large burns too hot, potentially producing excess soot, a dangerously large flame, or a container that gets too hot to safely handle. Wick sizing charts, which recommend a wick size based on both the wax type used and the container's diameter, exist because this genuinely varies by both factors together — the same wick size that works well in one wax type and container size can perform quite differently in another combination.
Different waxes have different melting and scent-throw properties
Soy wax is popular for a cleaner burn and eco-friendlier profile, generally has a lower melting point, and is often praised for good "cold throw" (scent noticeable from an unlit candle) though sometimes considered to have somewhat weaker "hot throw" (scent released while burning) compared to some other waxes. Paraffin wax generally offers strong scent throw and vibrant color retention, historically the most common candle wax, though some consumers prefer to avoid it based on its petroleum origin. Beeswax burns cleanly with a natural, mild honey scent of its own, but blends less predictably with added fragrance oils and is typically more expensive than the other options. None is universally "best" — the right choice depends on priorities around scent throw, burn cleanliness, and cost.
Heating wax involves a real fire risk worth taking seriously
Wax, especially paraffin, can ignite if overheated — heating wax on a stovetop directly, rather than using a double-boiler method, or leaving heating wax unattended, are both genuinely risky practices, not just amateur mistakes to laugh off. Using a thermometer to monitor wax temperature and staying within the specific wax's recommended melting range, rather than heating by eye or guesswork, is a real safety practice, and a small kitchen fire extinguisher rated for grease and oil fires (not a water-based one, which can spread a wax fire) is worth having on hand specifically for candle-making sessions.
Fragrance load has a real maximum before problems occur
Adding fragrance oil beyond a wax's recommended maximum fragrance load doesn't simply make a stronger-smelling candle — it can cause the fragrance to separate from the wax over time, create safety issues with an unstable burn, or in some cases affect flash point and fire safety margins the wax was originally tested and rated for. Following a specific wax and fragrance oil's recommended maximum load, rather than assuming "more is stronger," produces both better and safer results.
The one thing people forget
Trim the wick to the recommended length (commonly around a quarter inch) before each burn, not just when first lighting a new candle — a wick that's grown too long from previous burns produces a larger, less controlled flame, more soot, and faster, less even wax consumption, and this simple, repeated maintenance step meaningfully affects both how a candle burns and how safely it does so over its full life.