Put a large stock pot of 4 quarts of water on to boil over high heat on the stove top. Add salt to the water
While waiting for the water to heat, gather your other supplies. Place a large bowl in the sink with 1 Quart of water in it. Do not add the ice until just before adding celery to the boiling water.
When water comes to a boil, reduce heat to medium so that water is at a hard simmer.
Add ice to the bowl of water in the sink.
Add your celery to the boiling water quickly using tongs or other tool. Only add a few pieces to the water at a time so that the water does not lose its boil
Allow the vegetables to stay in the water just long enough to begin to change colors. You'll notice the color brightens.
Remove the celery and plunge immediately into the ice water bath. Allow to soak there for 2-3 minutes.
Remove the vegetables to a paper towel lined tray to dry.
Use the paper towel to squeeze the celery gently and remove as much water as possible. Then lay the celery out onto a baking sheet lined with parchment paper. Do not allow the pieces to touch each other. Freeze for 2-6 hours.
Once frozen, measure quantities into resealable plastic bag. Squeeze as much air as possible from the bag and seal. Label the bag and place into the freezer.