Recipe

Slow Cooker Corned Beef With Guinness Gravy

Tender corned beef cooked low and slow, then finished with a savory Guinness onion gravy and crisped edges if you feel like showing off.

By Matt Campbell

•

4.8

A sliced slow cooker corned beef brisket on a platter with glossy Guinness onion gravy and potatoes in the background

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Corned beef in a slow cooker is already a win. It is low effort, high comfort, and it makes your house smell like you have your life together. But if you have ever thought, why does my corned beef taste good but kind of one note, this is the fix.

We are taking that classic slow cooker corned beef and giving it a little glow up: a quick sear for deeper flavor (optional but worth it), a bed of onions and garlic, and a splash of Guinness that turns into a savory, slightly sweet onion gravy. The meat comes out sliceable and juicy, the veggies soak up all the good stuff, and you get a sauce that makes you pause mid-bite and nod like, yep, that was the move.

A slow cooker insert filled with onions, garlic, corned beef brisket, and stout before cooking

Why It Works

Low and slow = tender slices: Gentle heat breaks down the brisket without drying it out.
Guinness plus onions builds instant depth: The stout adds roasted malt notes and a subtle bitterness that balances the salty cure.
Separate gravy, better control: You get a sauce that tastes intentional, not just salty cooking liquid.
Flexible finish: Serve it straight from the pot for cozy vibes, or broil slices for crisp edges when you want that deli-style energy.

Pairs Well With

Storage Tips

Cool it fast: Get the meat and veggies into shallow containers within 2 hours. Store the gravy separately if you can.

Fridge: 3 to 4 days. Slice the corned beef once cold for cleaner slices and easier reheating.
Freezer: Up to 2 months. Freeze sliced meat with a little gravy or broth to prevent dryness.
Reheat (best method): Warm slices in a covered skillet with a splash of gravy or broth over low heat until just hot.
Crisp-edge reheat: Pan-sear slices 1 to 2 minutes per side, then spoon warm gravy over the top.

Leftover ideas: Reuben melts, corned beef hash, chopped into scrambled eggs, or tucked into a grilled cheese with Swiss.

Common Questions

Do I need to rinse corned beef first?

I recommend a quick rinse and pat dry. It knocks off excess surface brine so the final dish tastes beefy, not aggressively salty. If you love it super salty, skip the rinse.

Should I use the spice packet?

Yes, but think of it as a starting point. The packet is usually mustard seed, coriander, peppercorns, and bay. In this recipe, it works great with the stout and onions.

What if I cannot find Guinness?

Any stout or porter works. If you want alcohol-free, use beef broth plus 1 tablespoon Worcestershire and 1 teaspoon brown sugar for that roasty balance.

Why is my corned beef tough?

It usually needs more time. Brisket gets tender when connective tissue fully breaks down. Cook until a fork slides in easily, then rest it before slicing.

How do I slice it so it stays tender?

Slice across the grain. If you are not sure which way the grain runs, look for the long lines in the meat and slice perpendicular to them.

Can I add cabbage in the slow cooker?

Yes, but add it late. Stir in wedges during the last 60 to 90 minutes on LOW so it stays tender, not mushy.

Matt Campbell

I have always had a huge passion for the culinary arts, people, working as a team, and so on. I wanted to pursue my love for cooking initially at Virginia Commonwealth University with a culinary arts degree; however, I instead decided to apply myself and acquire more practical skills. My end goal is to eventually open my own restaurant or similar establishment.

Kitchen Essentials

6-quart slow cooker (or larger)
Large skillet (for optional sear)
Tongs
Cutting board and sharp knife
Small saucepan (for gravy)
Fine-mesh strainer (optional, for a smoother gravy)

The first time I made corned beef in a slow cooker, I was proud. The second time, I realized I was basically making the same pleasant, salty pot roast situation on repeat. Good, sure. Memorable, not really.

So I started treating the cooking liquid like it mattered. A bed of onions, a little stout, and a quick gravy later, the whole thing clicked. It tasted like the version you get when someone actually cared and did not just dump in water and hope. Now this is my go-to when I want a hands-off dinner that still feels like I tried.

Slow Cooker Corned Beef With Guinness Gravy

(4.8 Reviews)

Prep Time 15 minutes

Cook Time 8 to 9 hours (LOW) or 4.5 to 5.5 hours (HIGH)

Total Time 8 hours 30 minutes

Servings 6

Ingredients

1 (3 to 4 lb) corned beef brisket, flat cut preferred, spice packet reserved
1 large onion, thinly sliced
4 cloves garlic, smashed
1 lb baby potatoes (or Yukon Golds, cut into 2-inch pieces)
4 large carrots, cut into 2-inch chunks
1 cup Guinness (or other stout)
2 cups low-sodium beef broth
1 tbsp Dijon mustard
1 tbsp brown sugar (optional, for balance)
2 tbsp butter
2 tbsp all-purpose flour
1 tbsp apple cider vinegar (or pickle juice), to finish
Black pepper, to taste
Optional finishing touch: 1 small head green cabbage, cut into wedges
Optional for serving: chopped parsley, whole grain mustard, horseradish

Note: Skip adding extra salt until the end. Corned beef brings plenty on its own.

Instructions

Quick rinse (recommended): Rinse the corned beef under cool water and pat dry. This keeps the final dish from tipping into too-salty territory.
Optional but awesome: sear it. Heat a skillet over medium-high. Sear the brisket 2 to 3 minutes per side until browned. This adds real depth to the gravy later.
Build the slow cooker base: Add sliced onion and garlic to the slow cooker. Nestle in the potatoes and carrots.
Add the brisket: Place corned beef on top, fat side up. Sprinkle over the spice packet. Add the Guinness, beef broth, Dijon, and brown sugar (if using).
Cook: Cover and cook on LOW for 8 to 9 hours or HIGH for 4.5 to 5.5 hours, until a fork slides in easily.
If adding cabbage: Tuck cabbage wedges into the slow cooker during the last 60 to 90 minutes on LOW.
Rest the meat: Transfer corned beef to a cutting board and tent loosely with foil for 15 minutes. This helps it stay juicy when sliced.
Make the Guinness onion gravy: Strain 2 cups of cooking liquid into a measuring cup (leave onions and veggies in the slow cooker to stay warm). In a small saucepan, melt butter over medium heat. Whisk in flour and cook 1 minute. Slowly whisk in the reserved cooking liquid. Simmer 3 to 5 minutes until glossy and slightly thick. Stir in apple cider vinegar. Add black pepper to taste.
Slice and serve: Slice the corned beef across the grain. Serve with veggies and spoon gravy over everything. Add parsley, mustard, or horseradish if you want it extra bold.
Optional crisp-edge finish: For deli-style vibes, place slices on a sheet pan and broil 1 to 2 minutes per side until the edges crisp. Then gravy it up.

Sliced corned beef brisket being cut across the grain on a wooden cutting board

Nutrition information is estimated.

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