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The regional table / Wyoming

Rocky Mountain Oysters

Published September 23, 2026 · Wyoming

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They are the testicles of bull calves, taken at castration, and there is no reason to be coy about it. The cooking question is the membrane and the soak.

The supply comes from an annual job of work that the federal government has described in detail twice. Joseph Nimmo, Jr., Chief of the Bureau of Statistics at the Treasury Department, reported to Congress in May 1885 on how the western range was run: two round-ups a year, "the spring or calf round-up, and the fall or beef round-up", and in the spring "the only work is to drive the cows with their calves into the corrals and mark the calves by branding and ear-slitting." Wyoming still runs on the principle that a calf is identified beside its dam — W.S. 11-20-222 requires unbranded calves to be shown to the brand inspector "at their mother's side". Forty-four years after Nimmo, the Department of Agriculture published the procedure itself. Farmers' Bulletin 1600, Dehorning, Castrating, Branding, and Marking Beef Cattle, written by W. H. Black and issued in 1929, opens its section with a sentence no euphemism survives: "Castration consists in the removal of the testicles of the male." It sets the age — "Bull calves from a few weeks up to 8 months of age may be castrated without serious consequences" — warns that a bull left past eight months "may become 'staggy'", advises that the work "should be done in cool weather", and notes that "it is not uncommon for cattlemen to perform all operations — castration, branding, and marking — at the same time." One correction to the story as it is usually told: the bulletin says that in round-up days "it was customary to brand fall calves in the spring and spring calves in the fall", so the branding pen was not only a spring affair.

The name is older and travels further than the Rockies. The earliest printing I could reach is a restaurant advertisement in the State Press of Macon, Georgia, for 29 October 1857, whose bill of fare runs through oysters from New York, Savannah and Brunswick, shrimps and crabs, venison and beef steaks, mutton chops, deviled ham and deviled terrapins, and then "Mountain Oysters" — printed without a word of explanation, between the terrapins and the turtle soup, in a city a long way from any mountain. Forty-one years later a Plattsmouth, Nebraska, butcher was advertising the same thing in the same company in the Semi-Weekly News-Herald of 16 December 1898: "sweet breads, calves' brains, calves' liver and bacon or spring lamb chops. Mountain oysters or a Spanish mackrel". The longer form turns up as a joke in the Falls City Tribune of 20 September 1907, reprinting the Tecumseh Tribune on a banquet promised to a defeated candidate, whose menu was to be "Rocky Mountain oysters fried, stewed or raw." Fried, stewed or raw is a fair summary of the historical treatments; the first is the one worth your time. Two honest notes on the evidence: Wyoming's own digitised newspapers are behind a Cloudflare wall that refuses scripts, so every dated printing quoted here comes from Georgia and Nebraska archives rather than from a Wyoming paper, and none of them says which animal supplied the dish.

Why this version works

Cornmeal in the dredge, and 350°F. Half cornmeal gives a crust that stays crisp for the ten minutes it takes to eat them, where straight flour softens as the steam comes through. Hold the oil at 350°F and fry in small batches: a crowded pot drops to 300°F, the crust soaks instead of setting, and the result is greasy.

A quarter to three-eighths of an inch, no thinner. Sliced thin they dry to leather before the crust colours. Sliced thick the crust is dark by the time the middle has set. At a generous quarter inch the interior firms in the two or three minutes the coating needs, which is the whole trick.

The membrane comes off, and everything depends on it. Each one arrives inside a tough white sheath. Left on, it shrinks hard in the fryer and turns the whole piece rubbery and difficult; off, what remains is a fine-grained pale meat that behaves like a sweetbread. Thirty minutes in the freezer firms the sheath enough to split it with a knife tip and strip it away in one piece.

The soak is part of the standard preparation, not a superstition. USDA's own nutrient database carries an entry described as testes "cooked, soaked and fried" — the soak is written into the federal description of the food. Two hours in salted water, changed once, pulls out blood and the faint metallic edge that comes with it. Milk or buttermilk does the same job and adds a little sweetness.

Ingredient notes

Dredge: three parts flour to two parts fine cornmeal, with salt, black pepper, cayenne and paprika. Season it more heavily than feels right — a lot of that seasoning stays in the bowl.

Frying fat: a neutral oil with a high smoke point, deep enough that the pieces float, and a thermometer. Lard is traditional, good, and smokes sooner; if you use it, hold 340°F instead.

The soaking water: a tablespoon of salt to each quart, enough to cover, changed once at the hour. If you would rather use milk or buttermilk, use it straight and skip the salt in the soak.

The fries themselves: two pounds, from a butcher or a rancher, fresh or frozen. Ask for calf fries and you will be understood anywhere cattle are worked. Bulletin 1600 describes them coming off the animal with three or four inches of the cord still attached; trim that away and discard it, along with any bruised or discoloured tissue. They should smell clean, of nothing much.

Step by step

  1. Firm them up. Spread the fries on a tray and freeze 30 minutes. They should be cold and stiff on the outside, not frozen through.
  2. Peel and trim. Slit the tough outer membrane lengthwise with the tip of a sharp knife, cutting only as deep as the sheath, and peel it off with your fingers. Cut away the cord and any discoloured tissue. Rinse.
  3. Slice and soak. Cut into rounds a generous ¼ inch thick. Cover with cold salted water, refrigerate 1 hour, pour it off, cover with fresh salted water and give it another hour.
  4. Dry them properly. Drain and press between towels until the surfaces are dry to the touch. Wet slices steam inside the crust and push it off.
  5. Set up the coating. Whisk the flour, cornmeal, salt, pepper, cayenne and paprika in a wide bowl. Put the buttermilk in a second bowl. Heat 2 inches of oil to 350°F in a heavy pot.
  6. Fry in small batches. Dip each slice in buttermilk, let it drip, then press it into the dredge on both sides. Fry 8 or 10 at a time for 2 to 3 minutes, until deep gold, turning once. Do not let the oil fall below 335°F.
  7. Drain and salt at once. Lift onto a rack — not paper, which traps steam — and salt the moment they come out. Serve hot, with lemon and hot sauce.
If they are chewy rather than tender, the membrane did not all come off; there is nothing to do for that batch but there is for the next one, which is to freeze them longer and peel more patiently. If the crust slid off in the oil, the slices went in wet or the buttermilk was too thick — dry harder and let more drip. If they are greasy, the oil was under temperature; bring it back to 350°F between batches and never put more than a third of the surface under at once.

Storage and make-ahead

Fried, they are worth eating for about twenty minutes and are poor cold. Cook what you will eat.

Trimmed, sliced and soaked, they keep a day in the fridge under a damp cloth and freeze for 3 months. Freezing them prepared is the practical way to deal with a branding-day quantity.

What to serve with it

Cold beer and lemon. Cocktail sauce is the usual accompaniment in the country they come from, and horseradish in it does more for them than ketchup.

Something sharp and raw on the plate — pickled onions, or a plain vinegar slaw — because everything else here is fried.

From the recipe box / Wyoming

Rocky Mountain Oysters

Calf testicles peeled of their outer membrane, sliced, soaked in salted water to draw the blood, and fried in a cornmeal crust until they are crisp outside and pale and firm within.

Prep
35 min, plus 2 hours soaking
Cook
20 min
Total
55 min, plus 2 hours soaking
Serves
6
Calories
270 per serving

Ingredients

Scale

Instructions

  1. Freeze the fries on a tray 30 minutes, until stiff on the outside.
  2. Slit the outer membrane lengthwise, peel it off, trim the cord and any discoloured tissue, and rinse.
  3. Slice a generous ¼ inch thick and soak in cold salted water 2 hours, changing the water once.
  4. Drain and press dry between towels.
  5. Whisk the flour, cornmeal, salt, pepper, cayenne and paprika together. Heat 2 inches of oil to 350°F.
  6. Dip each slice in buttermilk, press into the dredge, and fry 8–10 at a time for 2–3 minutes, until deep gold.
  7. Drain on a rack, salt immediately, and serve hot with lemon and hot sauce.

Nutrition

Fat15 g (3 g saturated)
Sodium620 mg
Protein16 g
Servingabout 5 ounces fried
Calories270
Cholesterol490 mg
Carbohydrates15 g (1 g sugar, 1 g fiber)

Nutrition is an estimate calculated from the listed ingredients and is provided as a courtesy, not as dietary advice.

Questions readers ask

How old is the name?

Older than the Rocky Mountain half of it, and older than the West's claim on it. "Mountain Oysters" is printed on a Macon, Georgia, restaurant bill of fare on 29 October 1857, between deviled terrapins and turtle soup, and a Nebraska butcher was advertising them beside sweetbreads and calves' brains in December 1898. "Rocky Mountain oysters" in full turns up in a Nebraska paper in September 1907. None of those printings says what animal is meant, so the name is datable and the definition, in print, is not.

What exactly am I cooking?

The testicles of young bull calves, removed when the calves are worked. USDA Farmers' Bulletin 1600 of 1929 puts it in one line — "Castration consists in the removal of the testicles of the male" — and explains why it is done at all: a steer produces a more refined carcass than a bull, which past two years old carries a heavy crest and too much forequarter to be worth much as meat. The organs are a by-product of that job, and eating them is the opposite of wasteful.

Is the cholesterol as bad as people say?

It is high and there is no point pretending otherwise. USDA's figures for the nearest analysed food, lamb testes cooked, soaked and fried, are 523 mg of cholesterol per 100 grams, against 21 grams of protein and under 5 grams of fat. So the meat itself is very lean, the fat in the dish is the fat you fried it in, and the cholesterol is several times that of a steak. Treat it as what it is: a plate to share at a branding, not a weekly dinner.

Do they have to come from the spring branding?

They mostly do, because that is when calves are worked, but the seasonal story is looser than it is usually told. Bulletin 1600 records that in round-up days "it was customary to brand fall calves in the spring and spring calves in the fall", and that cattlemen often did castration, branding and marking in one session. It also says the work "should be done in cool weather", which is the real constraint: not the calendar, the temperature.