Squeeze the lemons to get fresh juice. You will want to use a lemon juicer with this amount of fresh lemon juice needed.
Strain out any seeds or pulp.
Add the ingredients to the inner pot of a pressure cooker. I used the Instant Pot 6 quart.
Close the lid and the venting according to the manufacturer's directions.
Using the manual setting, set the timer for 1 minute on high pressure.
It will take at least 10 minutes to come to pressure. After it has come to pressure and counted down the minute, carefully do a quick release following the manufacturer's directions.
Using mitts, carefully pour the lemonade concentrate into a container with a lid. Refrigerate for about 6 hours or until very cold.
Just like the frozen lemonade concentrate you can find in your freezer section, the ratio to 3:1. Fill a large pitcher with a little over 6 cups of water and ice. Add the concentrate and stir. You can also do a single serving with six ounces of water and two ounces of concentrate.
Time coming to pressure is included in the prep time.