This slow cooker Guinness corned beef is the kind of St. Patrick’s Day supper that feels familiar but still a little special every time you make it. Out here in the Midwest, corned beef has long been a late-winter treat, something you’d see on church potluck tables and family gatherings when the snow was still piled high. In this version, everything hinges on one simple mixture: dark Guinness stout whisked with whole grain mustard, brown sugar, pickling spices, and bay leaves. You just pour that over a raw corned beef brisket in the slow cooker, put the lid on, and let time and gentle heat do the rest. The beer and spices sink into the meat, giving you a tender, deeply flavored roast that feels like it’s been bubbling away on Grandma’s stove all day—without you hovering over it.
Serve thick slices of the Guinness corned beef alongside buttery boiled potatoes or mashed potatoes, with simple steamed or buttered cabbage and carrots on the side. A spoonful of the cooking juices over the meat and vegetables ties everything together. Warm rye bread or crusty rolls are perfect for soaking up the juices, and any leftovers make wonderful sandwiches the next day with a smear of mustard. If you enjoy a drink with dinner, pour a small glass of Guinness or a cold lager to echo the flavors in the pot.
Slow Cooker Guinness Corned BeefServings: 6
Ingredients
3 to 3.5 pounds raw beef corned brisket, with seasoning packet removed and discarded
1 (11 to 12 ounce) bottle or can Guinness stout (or other Irish-style stout)
2 tablespoons whole grain mustard
3 tablespoons packed brown sugar
2 tablespoons pickling spices
3 dried bay leaves
1 medium yellow onion, peeled and thickly sliced (optional, for under the brisket)
1 cup water (optional, only if needed to almost cover the brisket)
Directions
Set your slow cooker on the counter and place the raw corned beef brisket inside, fatty side up. If using the onion, lay the onion slices on the bottom of the slow cooker first and set the brisket on top of them like a little rack.
In a medium bowl or large measuring cup, pour in the Guinness stout. Add the whole grain mustard, brown sugar, pickling spices, and bay leaves.
Whisk or stir the Guinness mixture until the mustard and brown sugar are mostly dissolved and the spices are well distributed. It will look a bit rustic with the mustard seeds and pickling spices floating around—that’s exactly what you want.
Carefully pour this one mixture all over the top of the raw corned beef in the slow cooker, making sure to wet the entire surface. If the liquid does not come at least halfway up the sides of the brisket, add up to 1 cup of water around the meat (not over the top) until it is almost but not completely covered.
Cover the slow cooker with its lid. Cook on LOW for 8 to 10 hours, or on HIGH for 4 to 5 hours, until the corned beef is very tender when pierced with a fork and beginning to pull apart at the edges.
Once the meat is tender, carefully lift the corned beef out of the slow cooker and place it on a cutting board. Tent it loosely with foil and let it rest for about 10 to 15 minutes so the juices settle.
While the meat rests, skim excess fat from the surface of the cooking liquid with a spoon. You can keep this liquid warm in the slow cooker to serve as a flavorful jus over the meat and vegetables.
Slice the corned beef against the grain into thin or medium-thick slices, depending on how you like it. Serve with some of the warm Guinness cooking juices spooned over the top.
Variations & Tips
For a full one-pot meal, nestle 1 1/2 pounds of peeled and halved small potatoes and 4 to 5 peeled carrots cut into chunks around the brisket in the last 3 hours of cooking on LOW (or last 1 1/2 hours on HIGH). Add cabbage wedges during the final hour so they stay tender but not mushy. If you prefer a stronger mustard flavor, stir in an extra tablespoon of whole grain mustard or a spoonful of Dijon to the Guinness mixture. For a slightly sweeter, more caramelized taste, increase the brown sugar to 4 tablespoons, or swap part of it for maple syrup. If you don’t have Guinness, use another stout or a dark lager; the character of the beer will change the flavor a bit, which is part of what makes this feel like it “hits different” every time. To reduce the saltiness, you can rinse the corned beef under cold water before placing it in the slow cooker, or even soak it for 30 minutes and pat it dry. Leftovers keep well and can be gently rewarmed in some of the reserved cooking liquid, or chilled and sliced thin for sandwiches with rye bread, mustard, and Swiss cheese.
