Cooking two steaks at different donenesses at one time

The simplest way to do this is with two Joules in two different containers, but with a little patience and planning, it can work with one sous vide setup! Here are some options: 

1. Place the medium steak into the bath and set the temperature for that doneness. When the steak has cooked, reduce the temperature to medium-rare and place the second steak in the bath. You can do this right away because it will help lower the bath temperature faster and in the short time you won't risk overcooking the second steak. When the second steak has reached its cook time you can remove both steaks and finish as desired.
   
   While this will give you the perfect results, it also increases the cooking time a bit. So there are two alternative and faster strategies:
   
2.  Add both steaks during preheating, and set the temperature to medium-rare. When the steaks have reached this temperature, remove one of the steaks and set it aside. Then increase the cooking temperature to medium and allow about one-third of the original cooking time for the remaining steak to reach this higher temperature. Finish both steaks with a quick sear. Although the medium-rare steak was set aside and cooled slightly, it won't be cold in the center, and the quick sear will make the surface crusty and hot.
3. Pre-cook the steaks to the desired doneness, and then reheat them later at the lower medium-rare temperature. This will ensure the doneness is right for all of the steaks, and they'll be warmed through.  You will want to make sure to properly chill and store the steaks in between cooking and reheating.