Drop point vs melting point vs congealing point: why does one wax have three temperatures?

One sunflower wax sheet gives a congealing point of 54 to 60 C and a drop point of 57 to 65 C. What each method measures, which sets a melt hold, and which compares suppliers.

A wax has three temperatures because three different tests are asking three different questions. A drop point is taken on the way up: the temperature at which the first drop of melted wax falls from a cup. A congealing point is taken on the way down: the temperature at which a cooling melt sets and stops flowing. A melting point or melting range, as printed on most cosmetic wax sheets, is a third method again. One candle-grade sunflower wax sheet shows the gap on a single material: congealing point 54 to 60 C by ASTM D938, drop melting point 57 to 65 C by ASTM D3954. The standard for congealing point says it plainly: its results "are usually lower" than drop melting point results. For a balm maker the choice is simple. Set the melt hold from the top of the highest-melting wax's drop point, and compare suppliers only on the same method, ideally a drop point.

• Same wax: congeal 54-60 C, drop 57-65 C
• Congealing reads lower than drop
• Rice bran wax: 77-82 C by USP 741
• Beeswax: drop 63.0, softening 64.0 C
• Melt hold: drop point top plus 5-10 C

Three tests, three questions

A natural wax is a mixture of long chain esters, acids, alcohols and hydrocarbons, each with its own melting behaviour. ASTM's own description of its dropping point test starts from that fact: "Waxes do not go through a sharp solid-liquid phase change when heated and therefore do not have a true melting point. As the temperature rises, waxes gradually soften or become less viscous." Because there is no single point, every method picks one moment in a gradual change and defines it closely enough to repeat. The moments are different, so the numbers are different.

Two of these matter little to a balm maker. The ASTM D87 cooling curve is "unsuitable for waxes of the petrolatum group, microcrystalline waxes, or blends", and a softening point turns up in papers more than on sheets. The three on cosmetic wax sheets are the drop point, the congealing point and the USP melting range.

The drop point family

Three standards give a drop point. ASTM D3954, "Dropping Point of Waxes", is the one written for every kind of wax: its scope says it "has been found suitable for all types of waxes including paraffin, microcrystalline polyethylene, and natural waxes". ASTM D127 is "used primarily for petrolatums and other microcrystalline wax", and "For pharmaceutical petrolatum, Test Method D127 usually is used." The European Pharmacopoeia method, 2.2.17, is the one cosmetic papers cite. Budai and colleagues, who used it on beeswax sticks in 2012, define the drop point as "the temperature at which the first drop of the melting substance to be examined falls from a cup under defined conditions". All three heat the wax and read the moment it softens enough to flow out under its own weight. That is late in the melt, which is why it is the useful figure for a melt hold.

The congealing point

ASTM D938 runs the other way. Its significance statement says the procedure "measures the temperature at which a sample being cooled develops a 'set' or resistance to flow", and that at that temperature "the wax may be at or close to the solid state, or it may be semisolid and quite unctuous, depending on the composition". For petrolatum, it says, the congealing property "is associated with the formation of a gel structure as the sample cools". It is written for petroleum waxes but printed on plant wax sheets too: Koster Keunen gives its sunflower seed wax only a congeal point, 74 to 77 C by ASTM D938.

One wax, two numbers: the same-material table

The cleanest way to see the gap is to find a sheet or a paper that measures one material two ways. These are the cases found.

Three things follow from the table.

The congealing point is the lower one, as the standard says. ASTM D938 states that it "is an alternative to Test Method D127. Results obtained are usually lower than the results obtained by Test Method D127 – IP 133, the amount of the deviation varying with the nature of the petroleum wax." The KERAGREEN sheet shows it on a vegetable wax, by 3 to 5 C.

The gap is not a constant. The ceresin sheet puts its congeal point just 1 F under its USP melting point. The candle sunflower wax puts its congeal point 3 to 5 C under its drop point. The beeswax stick bases put drop point 1 to 4 C under softening point, and the gap widened as the wax was diluted. No single offset turns one method into another.

Dilution moves the numbers, but less than you might expect. Adding 40 percent sunflower oil to beeswax lowered its drop point by only 1 C, from 63.0 to 62.0. Only at 60 percent oil, with glycerol and lanolin in the mix, did it fall to 56.0 C.

Why congealing point reads lower

The direction of the test explains most of it. A congealing point is read as a melt cools, and fats and waxes crystallise below their melting point, not at it. They need some supercooling before crystals form at a useful rate, so a congealing reading is taken after that lag. A drop point is read as a solid warms, and records the moment it has softened enough to flow from the cup, which is near the top of the melting range. The physics of the lag, and why a jug can sit liquid at 60 C and then set in ninety seconds, is on crystallisation and cooling rate.

The second reason is what each test calls the end point. "Develops a set" can happen while the wax is still "semisolid and quite unctuous", in the words of D938, so a congealing point may be reached with a good part of the material still soft. A drop needs enough of the crystal network gone for the wax to run. Neither is a clear point, the temperature at which a melt is fully transparent, and no sheet in this set reports one.

The material matters too. A natural wax melts across a range set by its mix of chain lengths, the same reason a butter has a melting curve rather than a point, as solid fat content shows, and fats that crystallise in more than one form add a further layer, covered on fat crystal polymorphism.

One wax type, three sheets: why supplier figures disagree

The commoner problem is two sheets for one ingredient, each using a different method. White beeswax is the easy test case.

For beeswax the three agree within a degree or two, with every range topping out at 65 C. That is a property of beeswax, not of the methods: the candle sunflower wax splits by 5 C at the top. Treat a match between methods as luck. Koster Keunen gives these for the other cosmetic waxes:

The sunflower row is the trap. A congeal point cannot be lined up against a melting range or a drop point, and because it usually reads lower, it understates where the wax finishes melting on heating. This site gives sunflower wax a drop point of 74 to 80 C on sunflower wax, and the upper end of that band is the one to plan a melt around. Rice bran wax raises the same question from the other direction: its 77 to 82 C by USP 741 sits close to carnauba, and grades vary, as rice bran wax sets out.

The name trap: two sunflower waxes, twenty degrees apart

Both sunflower sheets here give a congealing point by ASTM D938, so they compare directly. Koster Keunen's sunflower seed wax: 74 to 77 C. The KERAGREEN candle wax: 54 to 60 C. A 14 to 23 C gap by one method is not a method effect. The two products do not melt alike.

The KERAGREEN sheet does not give an INCI name or a composition. It describes "KERAGREEN Cast Sunflower Vegetable Wax" and says it "Makes very white candles that can be easily colored". Its needle penetration at 25 C is 25 to 35 tenths of a millimetre by ASTM D1321, softer than the 2 to 6 that KahlWax gives for its cosmetic sunflower wax on the hardness page. Whatever it is made of, it does not behave like Helianthus Annuus Seed Wax in a balm, and a formula written for one will not set the same way with the other.

The word "sunflower" on a label is not a specification. Check the INCI name, then check the melting figure by the method stated; sourcing ingredients covers what to ask for before you buy.

Which number sets the melt hold

Use the drop point, and use the top of its range. The melt has to take every wax in the formula fully into solution, and a drop point is the published figure closest to the end of the melt on heating. The rule on this site, set out on undissolved wax specks, is to hold above the highest-melting component, not an average of the blend, for ten minutes, and fifteen for a rescue. That means:

1. Find the highest-melting wax in the formula. One percent of carnauba outranks fifteen percent of beeswax here. The hold is set by the highest single material, whatever its share.
2. Take the top of its drop point range. If the sheet gives a USP melting range instead, use the top of that. If it gives only a congealing point, as for Koster Keunen sunflower wax, do not hold at that figure: the drop point is usually higher, so use a published drop point for the same wax or add a wider margin.
3. Add 5 to 10 C, and hold for ten minutes, stirring. For beeswax at 61 to 65 C, that gives the 72 to 75 C bulk melt in the specks page table. For sunflower wax with a drop point to 80 C, it gives the 85 C melt on the sunflower page.
4. Check the result, not the thermometer. The cold tile test on the specks page shows whether anything stayed undissolved. Glinting points mean the hold was too cool or too short.

Why not the congealing point? Because it is the wrong direction. A congealing point tells you where a cooling melt sets. A hold set there can sit below the drop point of the same wax. With the KERAGREEN figures, a hold at the top of the congealing range, 60 C, would be 5 C under the top of the drop point, 65 C. That is the kind of shortfall that leaves specks.

Why not a softening point? No supplier sheet in this set prints one. In Budai's samples it ran 1 to 4 C above the drop point.

Where the congealing point is useful

It answers the cooling question. A congealing point is the nearest published figure to where a cooling melt of the neat wax develops a set, which is the edge the pour window guards: the pour temperatures page says "The highest-melting structurant in your formula sets the floor of the pour window". Diluted by oil in a balm, the set comes lower, so use the pour page's windows by product rather than a sheet figure.

Which number compares suppliers

Compare drop point with drop point, by the same standard, and never one method against another. Of all the methods on the sheets, ASTM D3954 is the one written for this job: its scope says the test is useful "in determining the consistency of waxes, and as one element in establishing the uniformity of shipments or source of supply", and it is the method stated to suit natural waxes. D938 and D127 are written for petroleum waxes. Failing a drop point, compare USP 741 with USP 741: like with like.

Do not convert by adding or subtracting a few degrees. The gap is under 1 C on one ceresin and 5 C on one candle wax, and ASTM says the deviation varies with the nature of the wax.

Within one supplier, compare each lot's certificate with its own specification. A specification range like 61 to 65 C is the band every lot must fall inside, while a certificate gives the figure for one lot. A lot at the top of the range will need a slightly longer or hotter hold than one at the bottom, and swings between lots are a common hidden cause of batch to batch inconsistency.

What none of these numbers tells you

A drop point is a melting figure for the neat wax or the bulk balm in a test cup. It says nothing direct about three things balm makers ask it to.

Heat performance in use. A beeswax balm with a drop point near 60 C still goes soft in a pocket at 32 C, because it loses structure across a range far below its drop point. That is a softening range question, and the ladder of real temperatures, from pockets to parked cars, is on balm melting in the heat. Raising the drop point helps, but the hard wax changes the whole melting profile, not one figure.

Hardness. Budai's 60/40 beeswax and sunflower oil sticks kept drop and softening points within 1.5 C of neat beeswax while losing 29 percent of their compression strength, as measuring balm hardness sets out. The fix for a soft balm is on balm too hard or too soft.

Your thermometer reading. A probe in a jug reads the liquid around it, not the solid flake in the corner. When a sheet says 65 C and the jug at 66 C still has flakes in it, that is usually time and surface area at work, not a wrong sheet. Probe placement, lag and calibration are on thermometer readings disagree.

Where DSC fits in

Differential scanning calorimetry heats a few milligrams at a set rate and records heat flow, and papers report the peak as a melting point, a fourth number. Budai and colleagues ran it at 10 C per minute on the same stick bases. In the sunflower oil series the drop point tracked the DSC peak closely (R2 0.9825); once candelilla joined the blend, the same correlation fell to 0.3370. A drop point is a good one-number summary for a beeswax base and loses track when a second wax brings its own melting peak, one more reason to set the hold from the highest-melting wax rather than the blend.

Checking a new wax at the bench

None of the standard methods is practical at home, and none needs to be. What matters is whether a new wax, or a new lot, dissolves in the hold already in use. Melt it in the usual oils with an immersed probe from the equipment list; if the melt is not clear by the end of the hold, the wax runs higher than the one it replaced, whatever the sheet says. Run the cold tile test, then pour one test tin and judge it on day three. If the new wax is a substitution, the wax substitution calculator rebalances the percentages, and waxes compared sets out what changes besides melting.

Where these numbers stop applying

The ASTM descriptions here come from the published scopes only; the standards themselves are paywalled, so nothing on this page describes their apparatus or heating rates. D938 states that congealing point reads lower for petroleum waxes. The KERAGREEN sheet shows the same order on one plant-derived candle wax, but no source here tests it across cosmetic plant waxes. Supplier figures are specification ranges, not lot measurements, and the KahlWax sheet names no drop point method. Budai's figures come from 3 g beeswax sticks, most with glycerol and lanolin, so they show how dilution moves the numbers rather than giving values for a tin balm. The 5 to 10 C margin is this site's working rule, not a value from any standard.

What carries over is the shape of the answer. A wax melts across a range, each method reads a different point in it, cooling methods read low and heating methods read high, and the gap between them varies by wax. Melt from the top of the highest drop point; compare suppliers like with like.

Reviewed and updated 26 October 2026. Spotted an error? Tell us and we will fix and log it.