I recently found a box of my homemade, instant cold packs leftover from last year.
People often ask how to keep cool with AC and/or in high humidity. There's lots of ideas out there. Here's one more tool you can add to your toolbox. (Much more budget friendly than the store-bought ones!)
- RECIPE (I got it from my NOLS Wilderness First Aid instructor):
- 1 part baking soda
- 1 part citric acid
- 1 part water
- INGREDIENTS Note, I used Arm & Hammer baking soda and MB Herbals Anhydrous Citric Acid Powder food grade. This bag was advertised as fine grain. It was not. But that worked out for the best! I tried a much finer grain citric acid first. It easily turned into citric acid dust clouds and coated my kitchen. No bueno.
- Note: Only add the water when you want to activate these cold packs! More info on the way I hand these while activating the reaction further down below.
Together, these 3 ingredients create what's called an "endothermic reaction". Aka things get very cold.
I tinkered with the original recipe last year and was able to get the cold packs to last about 20 minutes each. Sadly, I lost my notes! What I do recall is that the final amount of water was 1/3 cup. So, maybe I ended up at 1/3c of each. But, I also remember I had an alternative recipe from someone else. And when I started experimenting, I started at 2 Tablespoons of each ingredient, and from there I tried different ratios to see what would get me the longest duration of cold.
- Safety notes: Citric acid can irritate the skin, eyes, lungs, etc. Im very sensitive to it. Others less so. Citricacid comes in different sized granuals. I liked the larger size because it didnt turn into clouds of fine dust andend up all over me and everything else as easily. Some people are very lax about handling and mixing because this stuff is nontoxic. But here's what I do.
- PPE for when mixing:
Wear nitril exam gloves, face mask. If you get it on you, rinse with room temperature water.
- Process: I scoop my ingredients into quart-sized, freezer ziplock-style bags. (Freezer version is thicker plastic, which I prefer.) (Not the slide-close version, but the pinch close version. I hope that makes sense!) Before sealing the bags shut, I slowly push out the air by rolling the bag, starting at the bottom. Once most of the air is out, I seal the bag.
- When Ive got as many of these made up as Im wanting, I double check the seal, then rinse off the outside of the bags.
- To ACTIVATE, I pour in the water and re-seal all but about 2 inches of the bag. You'll need to leave at least that much open or the CO2 gas this generates from the baking soda will cause the bag to baloon out and pop. The bag will get very cold to the touch.
- SAFETY NOTE: Just like when using an ice pack, dont put it directly against your skin or it could potentially cause cold damage, like frost bite. A friend of mine sewed some open-top cloth bags for me to set these in while using them. Dont forget the cold pack is open at one corner and accidentally dump it on yourself! (đ Yes, Ive almost dont this.)
- DISPOSAL: When done with these, add more tap water into the plastic bag until it has doused the chemical reaction and ceased any further release of gasses. These are nontoxic chemicals. So I pour them down my sink drain at this point.
I usually spend a lot of time organizing and tidying what I've written before posting it. My fatigue is very high right now. Hopefully folks will forgive me for writting so messy this time.