Add ground coffee and water to the Instant Pot insert and stir to mix.
Place the lid on the Instant Pot, lock and set the valve to sealing position (not venting).
Select pressure cook (or manual) high pressure, and set the timer for 5 minutes.
When cook time is finished, allow for a complete natural pressure release.
Combine ground coffee and water (using a 1:4 ratio) inside a container and stir to mix.
Cover and let it brew for at least 12 hours out of direct sunlight or inside the refrigerator.
Strain your Cold Brew Iced Coffee Concentrate to remove coffee grounds.
In a jug, pitcher, or carafe mix together 1 part iced coffee concentrate and 1 part water.
If desired, add milk (regular milk or condensed milk) and sweetener to taste.