I Want My Tealights to Burn for Several Hours Without a Huge Flame — How Do I Choose the Correct Wick for the Cup Diameter?

A bigger wick does not buy you more hours

Makers chasing a long tealight burn often reach for a thicker wick, expecting a stronger, steadier flame to last longer. It works the other way. A tealight holds a fixed few grams of wax. A larger wick draws that fuel up faster, throws a taller flame, heats the thin aluminium wall more and finishes sooner. A smaller wick that just keeps the pool liquid and the flame steady gives the longest, calmest burn the cup can deliver.

So the real question in the title is: what is the smallest wick that stays alight to the bottom of your cup without drowning? That is an empirical answer, and since CSI publishes no wick sizing chart, no flame height and no burn rate per wick, the answer comes from your own test sheet, not from a table.

Measure the cup before choosing anything

CSI sells two empty tealight formats: the standard aluminium cups (₹94.40 for 10, ₹649.00 for 100) and Big Tealights empty cups (₹118.00 for 10, ₹1,180.00 for 100). Neither listing gives an internal diameter or a fill weight, so take a ruler to the inside of the cup and note the diameter at the rim, then weigh a filled cup to learn how much fuel it holds.

Those two numbers frame the whole test. The diameter tells you how wide a pool the flame has to keep liquid; the fill weight tells you how much fuel there is to spend. A wider cup needs a little more heat to keep its edge melting; a deeper fill gives more hours for the same wick. Write both on the top of your test sheet, because a result from one cup format does not transfer to the other.

Which CSI wicks are realistic candidates

CSI does not list a dedicated tealight wick. That is worth saying plainly, because it shapes the shortlist: you are borrowing wicks designed for small jars and adapting them by length. Three options are worth a place on the test sheet, and one is not.

The wooden wick line is there to make a point about economics rather than performance. At ₹4,130.00 per 100, one wooden wick costs ₹41.30, while one standard cup costs ₹649.00 ÷ 100 = ₹6.49. Nobody pays six times the price of the vessel for the wick in a tealight; save wooden wicks for jars where the crackle and the look are part of what the customer buys.

A test matrix that answers the question

Change one thing at a time. Use the same wax, the same oil and the same load across every cup, and vary only the wick and its length. A suggested starting matrix uses CSI 464 soy wax with Lavender at 6% of total weight, the bottom of the stated load range on its product page. That is a deliberately modest load for such a small pool, and the point is to keep the oil constant so that the wick is the only variable.

Run three cups per cell (a suggested starting point) so that one odd wick does not decide the result. Burn each to the end on a heat-proof tray, away from draughts, never unattended, and record the clock time at lighting and at extinction.

Decide your limit for a "huge" flame before you light anything, in millimetres, and write it on the sheet. Choosing the threshold after seeing the results is how makers talk themselves into an oversized wick.

What else moves the result

The wax matters. A soy container wax such as CSI 464 and a coconut-soy blend such as CSI 468, whose page states a melt point of 50–53°C, will not draw up a wick in exactly the same way, and paraffin pellets behave differently again. If you change wax after approving a wick, the approval no longer stands.

Fragrance and dye matter too. Some oils thicken the melt pool or leave residue on the wick; dye adds particles the wick has to carry. Unscented, undyed tealights are the easiest to wick, which is why the matrix keeps the load low and leaves colour out. If the final product is coloured, add the dye only after the wick is chosen, then run one more confirmation burn.

Finally, record the weight of each cup before and after burning. The difference, divided by the hours it burned, gives you a grams-per-hour figure for each wick in your cup. That number lets you predict the burn of a slightly fuller or lighter pour without repeating the whole matrix.

Buy this to test, then buy this once validated

The test kit below covers both cup formats and both Eco wick sizes. It is sized for the matrix above with some spare.

Once one wick wins in one cup at one load, the production order is simple: the 100-pack or 500-pack of that cup, the Eco wick that won in a pack that matches the cup count (both Eco sizes cost the same per wick at every pack size, so buy what you need), and wax in 1 kg or 10 kg packs. If you are scaling to hundreds of units, the companion arithmetic is a straight multiplication of your weighed fill.

One last practical point. A tealight that burns longest in a still room may behave differently in a draughty hall or on a windy balcony, where a small flame gutters and a large one dances. If you know where the buyer will use them, run your final confirmation burn in similar conditions.

Where this page fits

CSI already has guides that cover parts of this question. This page turns the product above into a raw-material list; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions