Bird Food

What Temperature Does Suet Melt?

Pure beef fat is not fully liquid until about 110 to 116°F (43 to 46.5°C), but a plain suet cake goes soft and starts to spoil from about 70°F (21°C). Both numbers are real, and the lower one is what decides when to switch to no-melt dough. The figures for each kind of fat side by side, what the no-melt ratings mean, and when to take suet down.

Suet does not melt at one temperature. Pure rendered beef fat finishes melting at about 110 to 116°F (43 to 46.5°C), but a plain suet cake softens, smears and starts to spoil from about 70°F (21°C). For a bird feeder the lower number is the one that matters, because a bird gets fat on its feathers long before the cake drips off the tree.

That is why two answers circulate. Lab measurements give the high figure, because they mean the point where fat is fully liquid. Bird feeding advice gives the low one, because it means the point where suet stops being safe to hang. Both are correct about different things, and the gap between them is where no-melt dough earns its place.

Why there is no single number#

Beef fat is a blend of many different fats, and each melts at its own temperature. As the fat warms, the softest part turns liquid first while the hardest part is still solid, so the block goes from firm to waxy to greasy to runny over a wide range rather than at a single point.

A 2010 study in the European Journal of Lipid Science and Technology by Yılmaz, Karakaya and Aktaş measured this with differential scanning calorimetry, a lab method that records heat taken up as a sample melts. In the fat the authors call tallow, and in intestinal fat, the melting curve showed two peaks: one at 7 to 9°C and the major one at 43.28 to 46.49°C. That second range, about 110 to 116°F, is where the last solid fat disappears. The first peak shows that part of the fat is already melting at 45 to 49°F.

The same study found fat from under the hide behaved differently. Its melting point was 29.0°C (84°F), with melting peaks at 3.56 and 23.55°C. That matters because, as Cornell's All About Birds puts it, suet is strictly "the hard fat around the kidneys and loins", but "in common usage, most kinds of beef fat are also called suet". A bag of free trimmings from the meat counter is often the softer kind.

The numbers by type of fat#

We gathered the figures from a lab study, an international food standard and the agencies and sellers who state one. They measure different things, so the table says what each number is.

Two things stand out. Kidney fat (the Codex "premier jus") and general tallow overlap, but the kidney fat range starts higher. Lard's range starts 8 to 10.5°C lower than either beef fat. Cornell advises against bacon drippings for a separate reason, nitrosamines, covered in what not to feed birds.

Titre is not a melting point. It is the temperature at which the fatty acids split out of a fat set solid again, and the Codex standard uses it to tell one fat from another. We include it because it is the only official figure we found that compares kidney fat, tallow and lard on the same scale.

What no-melt ratings mean#

A no-melt cake is still built on beef fat. Every ingredient list we read puts rendered beef suet next to corn, peanuts or oats, and the Toronto store names cornmeal and oat flour as the stabilizers. The grain holds the cake together after the fat inside has gone soft. The sellers rate these cakes well above anything plain fat can do:

Read these as marketing claims, not test results. None of the pages says how the figure was measured, in sun or shade, or for how long. One chain gives two numbers: a Wild Birds Unlimited store in Toronto says no-melt holds to 110 to 115°F, while the company's own product page says 130°F. Use the lowest stated figure for any brand you buy.

The ratings also reach the top of the melting range for pure fat. A dough rated over 120°F is being held together by its grain at a temperature where beef fat, on the lab figures above, is fully liquid. For choosing between a cake and a log, see suet cake vs suet plug; for mixing your own summer dough, see homemade suet recipes.

Why 70°F and 110°F are both quoted#

The 70°F figure comes from the feeder side. Terry W. Johnson, writing for the Georgia Department of Natural Resources, explains that suet was long fed almost only in winter "because it melts and spoils rapidly when temperatures soar above 70 degrees Fahrenheit." He is describing a cake that softens and goes off, not a puddle.

The 110 to 116°F figure describes fat turning fully liquid. That is the right number for rendering on a stove and the wrong one for a feeder, where the cake has failed long before it gets there.

Our own pages state it two ways. The suet guide says plain suet begins to soften around 80°F and slumps above about 90°F; the suet feeder guide says it melts and goes rancid above roughly 70°F. Both fit the sources: the low 70s is where trouble starts, 80 to 90°F is where you can see it. The switch to no-melt belongs at the start of that range, not the end.

What soft suet does to birds#

Cornell's All About Birds gives the reason the low number matters. Rendered suet "keeps much better, but can still get soft during warm weather. When suet gets soft, it can coat belly feathers, a dangerous situation especially in spring and summer when birds are incubating". It adds that "tiny pores on the birds' eggs may get clogged, preventing the developing embryo from getting enough oxygen."

Cornell's warning points at spring and summer, the same weeks the first warm days arrive and the season covered in nesting season feeding. A cake that was fine in March can be soft by May without ever dripping.

Raw fat is a stricter case. Cornell says "Raw suet grows rancid quickly when temperatures are above freezing; don't offer that except in winter." Unrendered fat still carries the impurities that rendering removes, and soft trim fat has the 84°F melting point measured above.

A temperature plan for the year#

Go by the daily high in the shade near the feeder, and change food by the forecast, not the calendar.

1. Below freezing. Raw or rendered fat both work. This is when suet does the most good, as in winter high-energy foods.
2. Above freezing to the 60s°F. Rendered plain cakes only, since Cornell limits raw fat to winter.
3. Highs reaching 70°F (21°C). Start the switch to no-melt dough at Georgia DNR's spoil point. Hang suet in the shade or refrigerate it at night, as the same article advises; where to hang a feeder covers shade and sun.
4. Highs at 80°F (27°C) and up. No-melt dough only, the line our suet guide draws. Put out smaller pieces and replace them more often, so nothing sits long enough to spoil.
5. Above the dough's rating, or any cake that leaves grease on your finger. Take it down. Offer mealworms or peanuts instead, and see summer feeding for the rest of the season.

In the hottest regions this means plain suet for only a few months of the year. The Southeast and Southwest guides cover local seasons. Whatever the weather, Cornell's fix for starlings is a suet feeder that makes birds hang upside down to eat.

What this page cannot tell you#

We found no published test of commercial suet cakes or no-melt doughs at controlled temperatures, so the product ratings are the sellers' word. The lab figures come from one study of cattle fat, read from its abstract. The Codex figures are titres, not melting points. And we found no measure of how often soft suet actually harms wild birds: Cornell's warning about feathers and eggs is a caution, and it gives no count.