I've been watching a show on Netflix called "Jericho". In one episode, they used fertilizer and water to make ice (needed to bring someone's fever down). A little research verified that it is indeed possible.

But aside from the show's medical reason, I wonder in a post-shtf scenario, would ice really be that useful? Other food preservation methods such as drying and canning seem more practical... But the whole ice making process seemed pretty low-effort, so maybe worth considering? Maybe as a "moral booster" for a special treat once in a while, like iced tea or something? What do you all think?

Of course, this would all depend on whether or not you have the extra fertilizer laying around unused... Maybe it's better just used on the garden?

I just realized this is probably in the wrong forum. Sorry! Feel free to move it elsewhere, mods.

Ice is only as pointless as the effort to make or preserve it. In a real SHTF situation, which means prolonged (> 1 year, or permanent) lack of electricity, I think folks will find all sorts of uses for ice - preserving meds for instance. My great-great grandfather in 19th century Wisconsin maintained an outbuilding that he filled with ice every winter, which lasted through the summer and into the following winter. So they had a use for an entire barnful of ice, year round.

I have very pleasant memories of time spent in a Minnesota ice house at the resort we frequented - a building full of ice and sawdust. The ice was cut from the lake during the preceding winter and stored for the summer patrons. Digging it out and delivering it was a pleasant taks on a hot summer day.

In a marginal situation, ice would be the least of my concerns. I would go to an evaporative cooler (an open box surrounded by wet cloth) to keep foods longer. If ice could be collected seasonally and stored - fine; otherwie, forget it.

I don't know about the fertilizer thing; a lot of these techniques shown on TV are often farfetched and fictitious. I wouldn't use the boob tube as a training manual.

the heat energy required to dissolve solid crystals of potassium nitrate (KNO3) into a liquid solution is endothermic, meaning that heat must be added from the surroundings which will cool those surroundings...potassium nitrate may be a large enough component of the fertilizer compounds commonly called potash (the third % number in a designation like 6-6-6) to produce an endothermic cold compress

Ammonium Nitrate is what's used in those instant "ice" packs. I don't see it as a practical means of long-term refrigeration. Although I suppose you could allow the water to evaporate and then re-use it.

Reframe the question: is coolth a survival value? I spent most of my life in the boreal forests: cooling things off was seldom an issue. Now I am in the land of perpetual heat, and see a lot of resources devoted to creating the chill in an emergency: generators sized to support ac systems, residential structures close to the water )and close to the storm surge) to access sea breezes. Michael Crichton included a high tech tent ac unit in Congo, suggesting that high temp/high humidity interefered with sleep patterns and caused a measurable decrease in human performance.

I'd reserve it for medical uses unless it can be harvested in winter & stored. I don't know if you can generate enough temperature differential to use ice as an intermediate step instead of direct cold packs.

There are a lot of things you can do to adjust to hot conditions without depending upon a generator and air conditioning. One of the simplest is to adjust your schedule. Do the heavy work between sunrise and 9 AM to take advantage of the cool. The midday siesta isn't laziness - it is a very smart coping strategy for dealing with the heat.

I once did a dig in the Grand Canyon, right next to the suspension bridge and along the trail, where we were digging by 4 AM, knocked off at noon, retreated to our cabin until dinner, and then returned to the site in the evening, once it was in the shade. Worked pretty well and avoided a lot of sunstroke.

Shade is critical. Many native cultures adapt a ramada-like structure, basically a roof with open sides, that keeps the direct sun out, but catches the breezes. If you are hydrated and sweating, the slightest breeze will cool you nicely.

Most of my hot weather experience has been in the arid Southwest, which typically features low humidity. There is a big difference between 100 degrees with 20% humidity and 100 degrees and 80% humidity. To me dry conditions are far easier to deal with. If it gets hot enough, generally over 106F, about the only thing you can do is limit your exertion.

Ice is a luxury. Nice to have and useful, but not necessary. Look at most lesser-developed nations between the tropic lines. Little to no ice access, but they do quite well.

As for fevers, well, usually they worry the parent more than necessary. If your kid isn't seizing, they're probably OK. Cool moist compresses work just fine if needed.

there is some pretty interesting information out there about clay pot evaporative cooling vessels, and reversing a Brigham Young University solar cone oven to radiate heat back into space to make ice... after all, space is just a couple of degrees above absolute zero

In a number of scenarios, anyone with ice would have a highly tradeable commodity. Both to obtain goods and services; or to be a very good neighbour in a crisis (e.g., keep meds cool).

Keep in mind that not all refrigerator/freezer technologies require electricity. Long before CFCs, the original refrigerators/freezers used an ammonia cycle. This required only a controllable heat source. This method lives on in propane RV fridges, for example.

if you live someplace where you can freeze water in the winter think about using plastic trash cans,the under sink kind,as big ice cube trays.a backyard shed with saw dust and some modern insulation would make a personal ice house.
i tried this many years ago as a lark.i froze a few blocks and shoveled the chips from my chainsawing firewood over them and a tarp over that.i did it because after the snow had melted out of my woodlot the snow,which had turned to ice,under the chippings had not melted and it struck me i could make and save ice.in a shady spot the blocks lasted a few weeks after the rest of yard was cleared.not much of a block of course,maybe a third was left but with more work i could of had ice until June in Minnesota.with a building maybe all summer.
this ice making talk sounds like the plot to Mosquito Coast!

I remember a high school physics experiment that involved pouring diethyl ether in a spoon partially filled with water. Blow on it, and the ether eavaporates and chills the water to freezing. Just add ether to the FAK, and have ready access to ice for cold therapy, and to a fine general anesthetic for emergency surgery. Dandy little fire starter, useful for starting internal combustion engines, too. Surprising that more folks don't carry it.

Check out Lehmans.com for Ammonia fridges,they're a bit pricey but,You could have Ice Cream/Ice 24/7/365 in Death Valley!

Rich...been meaning to search the RV centers for a used propane (ammonia and water system)refrigerator for a couple of years now... much cheaper than a new system, but really haven't needed one during hurricane season... there are a few remaining "stilt homes" off the mouth of the local river that still have ARKLA (Arkansas and Louisiana Gas Company) full sized refrigerators... most are propane, but some older ones kerosine fueled

Maybe I am overthinking it, but if you can take food and drop it into a box, and that will keep it fresh for 2 weeks instead of 24 hours, that seems to be a survival advantage.

RV fridges, or other absoprtion fridges can be used with almost any heat source, including the sun. Having a labor free way to keep food fresh seems like a major edge.

Having drinks that are cold in the summer, or a cold rag for a child with a fever.


Can you fake it? Sure, wrap a glass in a cloth, soak it with alcohol, and you can get it to make ice, but that is a long nasty process, and your booze is gone......