The regional table / Wisconsin

Bratwurst Simmered in Beer and Onions

Published September 22, 2026 · Wisconsin

There are two ways to ruin a bratwurst and a hard boil does both at once: it bursts the casing and it wrecks the beer.

Start with what the federal government does not say. Title 9, part 319 of the Code of Federal Regulations is the list of meat products the United States defines by name — it gives standards for frankfurter, bologna, knockwurst, bockwurst, braunschweiger, Italian sausage, fresh pork sausage and dozens more, down to the percentage of livers in a liverwurst. Search the whole of part 319 for the word bratwurst and it appears zero times. The nearest thing that binds anyone is § 319.141, which says that "Fresh Pork Sausage" is "sausage prepared with fresh pork or frozen pork or both, but not including pork byproducts", that "The finished product shall not contain more than 50 percent fat", and that water or ice may be used "in an amount not to exceed 3 percent of the total ingredients used". That is the entire legal specification for the thing you are about to cook. A bratwurst in this country is a fresh pork sausage seasoned however the butcher who made it seasons it, and the definition belongs to that butcher rather than to Washington.

The printed record is similarly oblique. Searching Georgia Historic Newspapers — which indexes syndicated national copy and is open to scripts where the Library of Congress is not — the earliest appearance of the word is not a recipe at all. It is in the Banner of the South at Augusta for 7 November 1868, printing the Hans Breitmann dialect ballad, in which the guests at a German-American beer party "ate das brot und Gersy broost, Do bratwurst und bretzel fine" and wash it down by the barrel. The tie to Sheboygan is on the national wire within a lifetime of that: an Associated Press dispatch in the Athens Banner-Herald of 29 March 1960 follows Hubert Humphrey campaigning through Wisconsin's Sixth Congressional District, where he "toured factories and sampled Sheboygan's famous bratwurst" — famous already, and worth a sentence of wire copy, in 1960. The plan for this article pointed at the America Eats Wisconsin file; whatamericaate.org answers 503 on every path, so nothing here rests on it and nothing here is attributed to it.

Why this version works

Brown first, then hold. Colour is a dry-heat reaction and it will not happen under liquid. Browning the sausages first in a hot pan sets the crust and renders enough fat to soften the onions in; the beer bath afterwards finishes the middle gently and holds a batch at serving temperature for as long as you need. Reversing the order gives you a grey sausage you then have to re-brown, by which point the inside is overcooked.

The bath stays under the boil. A bratwurst casing is a taut skin around fat that expands as it heats. At a rolling boil the fat inside goes past its expansion, the skin fails, and the sausage empties itself into the pan. Held at 180 to 190°F — steam rising, no bubbles breaking — the interior comes to temperature slowly enough that nothing bursts, and the sausage can sit there for half an hour without suffering.

The onions are the sauce, so give them time. Two large onions sliced thin and cooked in the rendered fat before the beer goes in will collapse into something sweet and jammy over twenty minutes, and the beer reduces around them rather than boiling them. Onions added raw to a bath that is already liquid stay crunchy and taste of raw onion no matter how long they sit.

Beer under the boil, for the same reason as any beer dish. Wahl and Henius's American Handy-Book of the Brewing, Malting and Auxiliary Trades of 1901 separates the two things hops put in a beer: "The oil gives to the beer aroma and flavor, the hop-rosin imparts the bitter taste and helps preserve the beer." The oil is volatile and the resin is not. Boil the bath and the aroma goes up the extractor hood while the bitterness stays and concentrates into the onions, which is how a brat bath turns acrid.

Ingredient notes

Beer: two bottles of lager or pilsner. Hop bitterness is a resin that will not evaporate, so it accumulates in a reducing pan — which rules out an IPA and rules out anything you would call aggressively hopped. A plain American or German lager is right.

Onions: two large yellow onions, sliced into half-moons about an eighth of an inch thick. Sweet onions collapse too far and turn to mush; a plain storage onion holds enough structure to be recognisable at the end.

Bratwurst: six fresh, uncooked links, roughly four ounces each. Fresh is the word that matters: a pre-cooked or smoked brat has already been through its temperature rise and will only dry out in the bath. The federal ceiling on a fresh pork sausage is 50 per cent fat and a good bratwurst is well under that, but it is still a fatty sausage and you want it that way.

Rolls and mustard: hard rolls, split but not hinged all the way through, and a brown or coarse-ground mustard. The roll has to be sturdy: it is holding a sausage, a fistful of wet onions and whatever bath liquid comes with them.

Step by step

Brown the sausages. Heat the butter in a large heavy skillet over medium heat. Add the bratwurst and cook 8 to 10 minutes, turning, until browned on all sides. They will not be cooked through. Move them to a plate.
Cook the onions. Add the sliced onions to the fat in the pan with the salt and pepper. Cook 15 to 20 minutes over medium-low heat, stirring now and then, until they are limp, golden and sweet.
Build the bath. Stir in the mustard and the caraway if you are using it, then pour in the beer and scrape the bottom of the pan. Let it come up to a simmer once, briefly, to take the raw edge off — then turn the heat down.
Hold the brats in it. Return the sausages and any juices to the pan, half-submerged. Adjust the heat so the surface steams but does not bubble, around 180 to 190°F, and hold 20 minutes, turning once, until the sausages read 160°F at the centre.
Reduce the onions. Lift the brats onto a plate and cover them. Raise the heat and boil the onions hard for 3 to 4 minutes, until most of the liquid has gone and they are glossy rather than soupy. The bitterness you concentrate here lands on the onions, so keep it short.
Serve. Split the rolls, lay in a sausage, heap on the onions and add mustard. If you are feeding people in waves, put the brats back into the bath at 180°F and they will wait half an hour without complaint.

If a casing has split, pull that sausage out of the bath at once and serve it first — it will keep emptying itself the longer it sits. If the whole pan boiled and the onions have gone bitter, drain the liquid off entirely, add a tablespoon of butter and a teaspoon of cider vinegar to the onions and cook them two minutes more; the fat and the acid cover a surprising amount of harshness. If the sausages browned too dark before the middle was done, finish them in the bath for an extra ten minutes rather than back in the dry pan.

Storage and make-ahead

Sausages and onions keep 3 days refrigerated, best stored together in what is left of the bath so the brats do not dry out. Reheat in a covered pan over low heat, not in a microwave, which splits casings.

They freeze for 2 months, again in the liquid. Thaw overnight and reheat in the pan; the onions come back better than the sausages do.

What to serve with it

A sharp, vinegary cabbage slaw or plain sauerkraut warmed through, and a potato salad dressed with vinegar and bacon fat rather than mayonnaise.

Cold lager, the same one that went in the pan.

From the recipe box / Wisconsin

Bratwurst Simmered in Beer and Onions

Browned first, then held in a pan of beer and sliced onions kept deliberately under the boil, so the casings stay whole and the onions become the sauce.

Prep: 10 min
Cook: 50 min
Total: 1 hr
Serves: 6
Calories: 610 per serving

Ingredients

Scale

6 links fresh uncooked bratwurst (about 1½ lb)
2 tablespoons unsalted butter
2 onions large yellow, sliced into thin half-moons
1 teaspoon kosher salt
½ teaspoon freshly ground black pepper
1 tablespoon brown mustard, plus more for serving
½ teaspoon caraway seeds, optional
24 ounces lager or pilsner, two bottles
6 rolls hard rolls, split

Instructions

Brown the bratwurst in the butter over medium heat, 8–10 minutes, turning. Move to a plate.
Cook the onions in the same fat with the salt and pepper, 15–20 minutes over medium-low, until limp and golden.
Stir in the mustard and caraway, pour in the beer, scrape the pan and bring it briefly to a simmer.
Lower the heat until the surface steams without bubbling, return the sausages half-submerged, and hold 20 minutes to 160°F, turning once.
Lift out the brats, boil the onions hard 3–4 minutes to reduce, and stop while they are glossy rather than dry.
Pile a sausage and a spoonful of onions into each roll and finish with mustard.

Nutrition

Fat	33 g (13 g saturated)
Sodium	1390 mg
Protein	22 g
Serving	1 bratwurst in a roll with onions
Calories	610
Cholesterol	85 mg
Carbohydrates	46 g (7 g sugar, 3 g fiber)

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

Questions readers ask

Why does the bath turn bitter?

Because it boiled. The bitter fraction of a beer is a resin that stays in the pan and concentrates as the liquid reduces, while the aromatic fraction is a volatile oil that leaves with the steam — a distinction the brewing trade had in print by 1901. Keep the bath below a simmer, use a lager rather than an IPA, and keep the final reduction to three or four minutes.

Can I cook them entirely on the grill?

Yes, over indirect heat, and plenty of people in Wisconsin do. The bath is worth the pan anyway for two reasons that have nothing to do with the sausage: it gives you the onions, and it lets you hold a dozen brats at serving temperature while the rest of dinner catches up.

Is there a legal definition of bratwurst?

Not a federal one. The word does not occur anywhere in 9 CFR part 319, the part that defines frankfurters, bologna, bockwurst and the rest by name. What does apply is the general standard for fresh pork sausage at § 319.141: no pork byproducts, not more than 50 per cent fat, and added water or ice capped at 3 per cent. Everything else about a bratwurst is the butcher's decision.

Should I boil the brats in beer before grilling, or after?

After, or better, neither. Boiling at any point is the mistake: at a rolling boil the fat inside the casing expands past what the skin can hold and the sausage empties into the pan. Brown first for colour, then hold in a bath kept at 180 to 190°F. That order gives you crust, a properly cooked middle, and a pan you can keep a second round warm in.