First, you’ll need to prepare your corned beef brisket ready for the slow cooker. With a knife, carefully cut it out of its packaging and, if it has a spice packet, set it to one side before proceeding to give your corned beef a quick rinse under your tap.
Once you have thoroughly given your brisket a wash, transfer it to your Instant Pot, placing it on the rack. If it has a side that has more fat on it than the other, pop the fattier side face down, so it will be able to absorb the flavour better.
If you purchased a corned beef brisket that came with a seasoning packet, carefully cut it open and evenly sprinkle the seasoning across the top of your corned beef brisket.
Before you begin cooking, go ahead and place your garlic cloves directly on top of the corned beef brisket. By doing this instead of placing the garlic cloves next to the beef, the meat will be able to better absorb the juices and fragrant aroma of the garlic.
Then, pour in 3 to 4 cups of water around the beef, being careful not to disturb any of the seasoning or garlic cloves. Alternatively, you can also choose to fill your Instant Pot Slow Cooker with broth, however, we recommend making sure to only use broth if your one has low salt content, as too much salt will make your corned beef taste bad.
Now, it’s time to switch the cooker on and let the magic happen. Carefully fasten the lid over the top of your Instant Pot, and switch over the steam vent to the ‘Sealing’ option. Then, switch on ‘Pressure Cook’ and set the time to 1 hour and 30 minutes, making sure to select ‘High Pressure’ so that the beef brisket will correctly cook.*
After your cooker has finished the allocated duration you have set, you can go ahead and lift up the lid and cease the pressure cooking.
Grab a plate and lay it next to your Instant Pot Slow Cooker.
With tongs, carefully remove the corned beef brisket from the cooker and transfer it to the plate. You can also remove the garlic cloves and pop them on the plate if you still want them, though many people choose to discard them at this point.
Immediately wrap the beef into aluminum foil to make sure it stays warm, and place in a preheated oven on light to medium heat.