Combine water, coffee, and salt in a vacuum-seal bag or use sous-vide safe zipper-top bag. Vacuum seal bags or use the displacement method to remove air from bags. Optionally, an oven-safe bowl covered with plastic wrap would work equally well.

Transfer bag to perforated pan. Slide pan into oven at rack position "2." Set oven to 150°F Sous Vide Mode. Sous vide coffee for 2 hours

Remove from oven and chill in an ice bath. Using a fine-mesh strainer, strain mixture.

Store in the refrigerator.