Standing in front of a shelf of tallow balms, how do you know which to buy — or what to use it on? St. Hildegard of Bingen had nine words for animal fat, and she chose between them by what each did on skin: soft fats spread and thin out, hard tallow holds where it is put. In this article we'll cover what her writing on tallow for skin tells you to do — how to match the tallow to the ailment, how to infuse herbs, and why what the animal ate matters.
How Long Has Tallow Been Used on Skin?
Longer than almost anything else in your bathroom.
Around AD 65, the Greek physician Dioscorides gave a long chapter of his De Materia Medica — the foundational herbal of the ancient world — entirely to rendered animal fats. His instructions are precise enough to follow today: take the fat from around the kidneys, wash it, melt it over a light bed of coals, strain it, melt it twice more — the last time without water — and store it lidded in a ceramic jar somewhere very cold. He was particular about the washing, too. Lard was washed in rainwater, ox suet in seawater, bull fat in running river water. He had looked closely enough to think the choice of water mattered.
A generation later, Pliny the Elder recorded the Latin name for the practice: axungia, from axis ("axle") and ungere ("to anoint"). Axle grease. The same rendered fat that kept Roman cart wheels turning had been taken up into the pharmacy. Pliny recorded that hog's fat grew more useful with age, whether salted or left pure. Dioscorides, writing in the same generation, called fat that had soured with age an enemy to the body. They were arguing about it from the start.
When the monasteries became the custodians of medical knowledge in the West, this material went with them. Monks copied the herbals, grew the plants those herbals named, and rendered the fats their recipes called for. The infirmary, the physician's house and an enclosed herb garden were drawn as a single group into the ideal monastery plan at St. Gall in the 820s.
So the practice behind a modern tallow balm is not a wellness trend that arrived in 2024. It is one of the oldest documented preparations in Western medicine, and the people who used it longest left instructions.
Who Was Hildegard of Bingen?
St. Hildegard of Bingen (1098–1179) founded and led the monastery at Rupertsberg. She was a composer, a theologian, and a visionary; in 2012 she was named a Doctor of the Church — a title recognizing the handful of teachers across two thousand years of Church history whose writing shaped doctrine — one of only four women to hold it.
She matters here because she ran an infirmary and wrote like it. Some time between finishing her visionary work Scivias and 1158, she compiled a book of natural medicine. What survives of it comes down to us as two separate texts, the Physica and the Causae et Curae, both in copies made after her death. The Physica alone runs to nine books, hundreds of entries, a great many of them giving recipes with quantities, proportions, and methods — the kind of detail you only write down if you have actually made the thing.
She cited no sources. She described herself as indocta, unlearned, and said her knowledge came to her as a reflection of the living light rather than from books. Historians have argued for a long time about how much of the classical medical tradition reached her through monastic libraries regardless. What is not in dispute is that some of what she wrote appears, sometimes almost word for word, in texts a thousand years older — and that some of it appears nowhere else at all.
Which Tallow to Use, and When
One difference decides everything else, and you can feel it with your hands.
Fat from ruminants — cattle, sheep, deer, goats, the cud-chewing animals — renders firm. At room temperature it sets into a dense white solid about the consistency of cold butter. Beef tallow does not begin to flow until around 105°F, above body temperature, and is not fully liquid until about 113°F.
Fat from everything else — pigs, geese, chickens — renders soft. Rendered chicken fat begins to flow at about 84°F, below the temperature of your skin. Lard sits between the two.
The split falls that way for a reason. Cattle, sheep, deer and goats ferment their food in a rumen before they digest it, and polyunsaturated fats are toxic to the bacteria doing that work. The bacteria protect themselves by hydrogenating those fats until they are harmless. What comes out the other end is largely stearic acid, which melts at about 156°F — higher than any other fatty acid found in animal fat in real quantity.
The animal then converts some of that back, and how much depends on how it was fed: grain finishing softens the fat, pasture leaves it firmer. Pigs, geese and chickens have no such filter at all.
Hildegard had no way of knowing any of that. She had the evidence of her hands: some fats set hard and some stayed soft, reliably, by species. Her words divide the same way — sepum for the hard ruminant tallows, arvina for the soft fats, plus sagimen, lardum, butyrum, medulla cervi, and three Middle High German kitchen words, smalcz, smero and unslet.
What that means when you're choosing one. Skin sits at about 90°F, and at that temperature roughly a fifth of beef tallow is still crystalline. It never goes fully liquid on contact the way a light oil does. It stays as a soft film across the outermost layers, and a lipid film in that position slows the water leaving through the skin. That is what you want for hands in and out of water all day, for cracked heels, for weather-burned cheeks, for anything you put on at night and want still there in the morning. A softer fat, or a tallow whipped to loosen it, thins out under the fingers and covers more ground — better for a scalp, or a large area, or anywhere a firm balm would sit in clumps. The difference is spread and melt, not depth: when oils have been followed into human skin under the microscope, the fat itself stops in the outermost layers, whichever fat it is.
Hildegard used both at once when a preparation needed both:
"...let him take a little goose-smalcz and as much deer and goat tallow as he can get, and make an ointment in this way..."
"...accipiat modicum de gensesmalcz et de cervino et hircino sepo quantum habere potest, ac ob hoc modo unguentum faciat..."
Enough goose fat to spread. Enough deer and goat tallow to keep it from running off. That is the same calculation behind every whipped tallow balm on the market today.
Why Herbs Belong in the Fat
Many of the fat recipes in the Physica are an herb worked into rendered fat.
For white leprosy — a medieval label covering a range of scaling skin disease — lily root pounded into aged lard:
"Take therefore the head of the lily root, and pound it hard together with aged arvina..."
"Accipe ergo caput radicis lilii, et illud cum veteri arvina fortiter tunde..."
For pain in the kidneys and loins — which she puts down to a weakness in the stomach — rue and wormwood pounded into bear fat and rubbed in beside a fire:
"...let him take rue and wormwood in equal weight, and add more bear fat than these, and pound them together..."
"...rutam et absinthium aequali pondere accipiat, et plus his de arvina ursi addat, et haec simul contundat..."
And for deep perforating ulcers, a base of goose fat and ruminant tallow holding a single drop of a pressed herb juice:
"...let him take a little goose-smalcz and as much deer and goat tallow as he can get, and add to them a little — like one drop, on a feather — of the juice of the dolo plant, and mix them together, and make an ointment in this way."
"...accipiat modicum de gensesmalcz et de cervino et hircino sepo quantum habere potest, ac eis modicum, velut guttam unam cum penna de succo dolonis addat et simul commisceat, ac hoc modo unguentum faciat."
The fats are the base. The medicine is one drop of juice.
Four centuries later, Banckes' Herbal was still giving the same construction in English: an herb "sodden in Swynes grece."
Why fat, and not water. Fat stays. A film of water is gone from skin in a couple of minutes; a fat film is still there hours later, sitting on the surface and softening the outer layers. Fat also keeps, without refrigeration or preservative. And it holds a family of plant compounds that water will not — the resins, the sterols, the triterpene acids, the aromatic oils.
It does not hold everything. Glycosides, tannins and mucilage stay behind, which is exactly why Hildegard reached for water and wine and milk as often as she reached for fat. Her main yarrow remedy for wounds is a decoction — the herb cooked in water, wrung out, bound on warm. Her iris ointment is pig fat cut with donkey's milk and strained through a cloth. Her agrimony salve is pressed juice stirred into melted lard until it comes out green.
Fat was not the answer to every herb. It was the right base for the ones it suited.
How to Tell Good Tallow from Bad
Two things come up again and again in Hildegard's recipes, and both still hold.
She usually specifies aged fat. Veteri arvina — old lard rather than fresh — outnumbers the fresh-fat recipes about four to one. Pliny had recorded the same preference a thousand years earlier. Galen gave the reason and drew the line: age makes fat hotter, thinner and sharper, which is what you want for a hardened swelling and not what you want for softening.
She cared how the fat was rendered. In one of the most vivid passages in the Physica:
"...let it be lightly greased on top with bear fat, so that the smalcz flows from it and the rendered fat flows from it. And let him collect that rendered fat after roasting, place it in a cloth, and press out through that cloth all the juice and all the rendered fat that is in it."
"...cum arvina ursi superius modice ungatur ut smalcz ab eo fluat, et sagimen ab eo fluat, et sagimen illud accipiat postquam assaverit, in pannum ponat, et omnem succum et omne sagimen quod in eo est per pannum illum extorqueat..."
The cloth is hers. The rest of the standard is older still. Dioscorides had set it down a thousand years earlier — melt over a light bed of coals, strain, then melt again, and again — and he was stricter than most makers are now. He boiled ox suet in wine until it lost its own smell, then bleached it in the sun until it turned white.
Rendering is what separates a good jar from a bad one. Fat melted slowly, at low heat, and strained well comes out pale and clean. Push the heat and the chemistry changes: take lard from 212°F to 266°F and the free fatty acids and peroxides both climb, the aldehydes rise by half again, and a roasted, nutty smell appears that was barely there before.
What rendering cannot do is make tallow smell like nothing. The international food standard for edible tallow says the smell should be characteristic — free of anything foreign or rancid, but not free of smell altogether. Beef fat is supposed to smell like beef fat.
It has its own scent compounds, and one of them is close to a signature. Chemists who identified it described it as smelling "tallowy and beef-like," and beef fat holds far more of it than pork, chicken or turkey — enough to tell the species apart in a lab. Grass leaves traces too. Some plant compounds pass into the fat almost unchanged, and rumen microbes turn the protein in fresh forage into others. Taking all of that out requires a deodorizer: the fat is held near 465°F under a near-vacuum with live steam run through it. No kitchen does that by accident.
So a faint beefiness underneath is normal. That is simply what beef fat smells like, and no amount of careful rendering removes it. A sharp, sour, or rancid smell is the problem — that one means the fat was rendered badly or has gone off. Two thousand years ago Dioscorides was judging fat the same way, by color and smell and whether anything bloody still ran off it, and it still sorts good from bad faster than any label claim.
Why Grass-Fed Tallow Is Different
Modern analysis has turned up something the medieval writers could not have seen, and it settles a question you cannot answer by looking at a jar.
Ruminant fats contain branched-chain fatty acids — built by rumen bacteria from the carbon skeletons of amino acids, then absorbed and laid down in the animal's own fat. Measured directly in rendered fats, a wide variety of them turn up across beef and mutton tallow. Chicken fat has none the instruments can find; lard has a trace. And pastured beef holds more of them than commercial — 1.89% of total fatty acids against 1.60%.
So the fat holds a record of what the animal ate, written into its chemistry. "Grass-fed" on a label is a claim someone made. This is a measurement.
There is a second marker of the same kind, though it settles mostly in milk rather than in depot fat. Phytanic acid begins its life as chlorophyll: green plants build chlorophyll with a long tail called phytol, rumen microbes strip that tail off, and the animal stores what is left. Organic dairy runs about half again as much of it as conventional, and researchers working on food authentication have proposed a threshold concentration for verifying grass-fed dairy on the strength of it.
The same family of molecules turns up somewhere unexpected. Vernix caseosa — the waxy white coating a newborn arrives in, made through the third trimester by the baby's own oil glands and shed skin cells — is roughly thirty percent branched-chain fatty acids by weight, and they are the same ones found in beef and dairy fat. A baby's skin builds them from scratch; it borrows nothing from anywhere. The same chemistry simply runs in two places that have nothing to do with each other: the gut of an ox, and the skin of an unborn child.
What Hildegard Would Tell You
Her writing comes down to four practical rules.
Match the fat to the job. Firm ruminant tallow for hands, heels, and anything you want still there overnight — it stays on the surface and slows what evaporates through it. Something softer or whipped for a scalp, or for covering a large area quickly.
Ask how it was rendered. Low and slow, well strained. Pale color and a clean, quiet smell are the signs of a good one. Sharp, sour, or rancid means the opposite. A faint beefiness underneath is just beef fat, and it belongs there. Keep the jar cool and out of the light.
Herbs steeped in the fat are the older form. That is what the fat is for — to hold the plant against your skin and stay there while it works.
Grass-fed is a real difference, not a marketing one. You can measure it. The fat of a pasture-raised animal contains molecules that a grain-fed animal's does not.
Hildegard would want to know which animal your jar came from and whether the fat was hard or soft, because she would use it differently depending on the answer. She had nine words for this stuff. We have one — and the differences those nine words described are still real, even though we stopped naming them. Which fat spreads and which one stays put. Which one is worth using for what. The fat has not changed. Only our vocabulary has.
Further reading
- Bathing Like a Medieval Nun (Yes, Really) — what monastic washing actually involved, and how often
- The Herbalist Trained by Heaven — Hildegard's life, visions, and how she came to write about medicine
- Holy Herbs and Sacred Serums: Inside the Pharmacy of Popes — the papal apothecary and what it kept on the shelf
