1smallhead of cabbageyou can use more, it just depends on how much fits into your pot
Instructions
Instant pot instructions:
Place the onions and garlic into the pot.
Next place the brisket into the pot.
Pour the beer, both, seasoning packet and water over the brisket. It should be just covered with liquid- if necessary, add more water.
Secure the cover onto the instant pot and set the instant pot to Manual High Pressure for 90 minutes.
When the cook time is up, let the pressure naturally release for 10-15 minutes (or longer if you have the time) and then do a quick release.
Remove the beef from the pot and leave the liquid in there. Slice the beef and place it into a warm oven while you cook the vegetables.
Add the vegetables into the pot with the liquid and set the instant pot to Manual High pressure for 5 minutes.
Once the cooking time is up, carefully do a quick release.
Serve immediately.
Slow cooker instructions:
Place all the vegetables into the slow cooker.
Next add the brisket.
Top this with the beer, broth, spice packet and water to just cover the beef (add a little more water to cover if necessary).
Cover and cook on low for 7-8 hours.
Slice and serve immediately.
Video
Notes
It's generally a good idea to use flat beer if you're making this in the instant pot, as carbonation and high pressure don't mix. That being said, I've made it before and survived to tell this tale, although I did notice that when I got to the quick release it was a bit messier. Either way proceed with caution and use safe pressure cooking practices as per the user manual that comes with your instant pot.