Cold Pack Gel

Yield: 5 cups

5 cups water
1 cup table salt
1.5 cups cornstarch
5 drops blue food coloring (optional to give the gel a traditional cold-pack look)
2 to 8 Zip-close plastic bags e.g. 2 gallon sized or 8 quart sized

Add water to a medium-large pot and place over high heat.
Add salt to the water and mix slowly until dissolved.
Add cornstarch to the water and mix slowly until dissolved.
Optional: Add food coloring to the water if desired and mix until blended.
Continue to stir the water mixture constantly and slowly until it begins to thicken.
Stir more rapidly for about 60-90 seconds while the mixture thickens quickly and begins to “boil”.
Immediately remove from the heat and continue to stir for another minute. The mixture will resemble thick pudding and become semi-transparent.
Set the pot on a wire rack and let the mixture cool for 30-45 minutes.
Open zip-close bag(s) and roll down the top to make a bowl shape with the bag. Using a large plastic serving spoon, carefully lift out the mixture from the pot and tap it into the bag. Continue to transfer the mixture into bag(s).
Carefully close bags making sure to remove as much air as possible.
Double bag each prepared bag and then place in the freezer. Bags will be ready to use in 30 to 90 minutes, depending on the size of the bag(s) how much mixture is in each bag.

Some tips:

Standard ziplock/zip-close bags work best for this. The slide-lock and easy-open bags are unnecessary and the additional plastic tends to get in the way.
As a low carb'er, you probably don't have cornstarch in your pantry. That's a good thing, except for this recipe! Here's a link to get some online at Amazon: http://amzn.to/2t0g2wu.
This recipe makes about 5 cups of cold pack gel. This is just about perfect to fill a 1-gallon ziplock/zip-close bag to about 3/4" thick, which feels about perfect. For the photo, I spooned half of the mixture into a gallon bag and split the rest between two quart sized bags. The photo was taken as I was finishing the second quart-sized bag. I then double bagged all three.
Remember to prevent frost burn by placing a dish towel, paper towel, or some other fabric-like material between your skin and the cold pack!
Food coloring is a dye and is difficult if not impossible to remove. If there is a chance your cold pack will be slept on, stepped on, smashed, or otherwise busted open, then do yourself a favor and skip the optional food coloring. On the other hand, you could choose to triple bag your gel and have all sorts of fun experimenting with different colors. Enjoy!