Of all the uses we have for electricity, keeping food cold is probably the most important use in the home. Keeping food cold, whether freezing or refrigerating it, is the most common method of food preservation in use today. We depend on it without thinking about it, much like many of the other conveniences we have in our modern society.
But what if the power goes out? How would we keep that food usable? Most refrigerator/freezer units will keep the food inside good for about 48 hours, without power, assuming that the doors are closed. So that gives us a little bit of time to come up with a plan B and put it into operation, but not much.
A full freezer will actually keep food frozen longer than one which is half-empty. That's both because of having a larger mass of frozen food inside, so the food helps keep itself cold, and by reducing the space taken up by air. Since the air moves out of the freezer when it is opened, to be replaced by ambient room air, each time the door is opened, there is new air to cool down to the freezer's temperatures. In other words, the food in the freezer has to absorb the heat in that air, warming the food somewhat.
This is even more serious in a refrigerator. Not only is the food not as cold, but there is usually more air space in a refrigerator, than there is in a freezer. So, the turnover of cold air for ambient air is more serious.
Food spoils because of bacteria eating it. Cold preserves food by slowing the metabolism of bacteria in that food. With a slower metabolism, the bacteria don't eat as much and don't multiply as rapidly. So, while food can still spoil in a refrigerator, it does so much more slowly than in ambient air. On the other hand, a freezer stops the metabolism of bacteria altogether, putting them in an inactive state until thawed. But it doesn't kill that bacteria. Most of them can survive freezing without a problem.
But keeping food cold, without refrigeration is difficult. In our modern society, we have no other means of doing so. However, that doesn't mean that there are no other ways. In fact, there are many other ways, both from our nation's past and from other parts of the world. Mankind has been dealing with how to keep their food cool for centuries, long before electric refrigerators hit the market.
While the methods of our ancestors might not work as great as having an electric refrigerator, the thing we have to keep in mind is that they worked for those people. So, if we needed them, they would also work for us. All we need is to be prepared to implement those methods, should the lights ever go out.
I say "be prepared" for a reason. That is, each and every one of these methods will require some preparation. They aren't something you can do in a moment. So, it's best to pick out the method or methods that you are going to use and implement them today, before you need them. That way, when you are in need, all you'll have to do is to move your refrigerated and frozen foods from the refrigerator to your alternate food storage and cooling location.
#1 Use the Cold
Probably the oldest method of keeping food cold is to use the cold that nature provides. If you happen to be fortunate enough to live in Alaska (or perhaps unfortunate enough, depending on your point of view), then refrigeration shouldn't be much of an issue. You can probably keep your milk cold, just by keeping it outdoors. If your house isn't very warm, you might not even need to put it outdoors.
During the pioneering days, people would build food cribs onto the sides of their homes, which were exposed to the outside air, while still protecting the food from predators. This would keep meat frozen through the wintertime, as long as it stayed cold. But once the first thaw came, they either had to cook and eat the meat, or throw it away.
Such a storage system would be possible, even today, for those who live in the northern part of the country. Of course, it's utility would be limited, as it would be very dependent upon the weather. It would be better to have some way of preserving all that snow and ice, for use when the weather is warmer.
Ice Houses and Ice Boxes
The real improvement on using the natural cold weather came when someone built the first ice house. This is nothing more than an insulated warehouse to keep blocks of ice in. Some of the best ice houses were underground, but the vast majority were above ground structures. Simple hay or straw was used as insulation, piling it over and around the blocks of ice.
Ice would be harvested from lakes and rivers in the wintertime. If you've got a young daughter, then you've probably seen the movie "Frozen" more times than you'd like. In the opening scene, men were out on the lake, cutting blocks of ice and carting them off to an ice house, much as they did in the past.
People would have an "ice box" in the home to put their perishable food in. the ice man would come around every few days, selling blocks of ice which had been stored in the ice house. In this way, they would have constant refrigeration, without the use of electricity.
The one problem with harvesting ice and having an ice house is that it is requires a community effort or a commercial effort. The more ice stored in one place, the better it will last. Harvesting and keeping enough ice for one family is not really practical, although it might be in conjunction with other systems.
One means of making it more practical is to build an underground ice house, keeping it above the frost line. Rather than harvesting ice, fill the ice house with water or allow it to become filled with rainwater. Then, allow it to freeze through the winter. The trick here will be to ensure that all the water freezes into ice, which is why I said to ensure that the whole ice house is above the frost line.
Every child who is old enough to have discovered swimming knows that the water is cooler than the air above it. That's what makes summertime swimming so much fun. Well, if that water is cooler than the ambient air, then it can be used to keep your food and drinks cool too.
Water, especially flowing water, tends to be cool because of evaporation. It takes an incredible amount of energy to warm water up enough for it to evaporate. While the water can absorb some of that heat energy out of the air, it is much more efficient for it to absorb it out of the larger body of water, cooling the water left behind in the process.
Of course, if the water has flowed down from the mountains, it will be even cooler yet. Higher altitudes are cooler, so it's natural to expect the water to be cooler too. Putting food in plastic bags or containers and immersing it in water will keep that food cool.
This is a common trick used by backpackers, fishermen and campers everywhere. While the water won't keep your beer as cold as the refrigerator, on a hot day it will still taste good. Even more important, in an emergency situation where you need to keep food from spoiling, any body of water on your property can be used for emergency refrigeration.
#2 Go Underground
People have probably been using underground storage for keeping food cool, about as long as storing it outside. A basic law of thermodynamics says that heat rises and cold drops. So, it stands to reason that it will be cooler underground than it is on the surface. On top of that, the sunlight doesn't hit underground areas very well to warm them up.
Caves may very well have been the first refrigerators ever used. Any cave will be cooler than the ambient air and a deep cave can become quite cold. People who had caves on their property quickly found that they were an excellent place to keep food, as long as they could keep the critters out.
Dug wells work pretty much the same. It was not uncommon for people in the Middle Ages to hang a jug of milk in the well, to keep it cool. The same could be done for butter, wine and mead.
Burying food underground in casks and barrels was also used to preserve and store it. This was especially good for nuts and dried fruit, both of which keep well over a prolonged period of time. Burying them prevented them from being exposed to heat, prolonging their natural preservation. Few insects or rodents would bother them, as the oak casks and barrels were difficult for them to eat their way through.
The Root Cellar
Of course, not everyone has a naturally occurring cave on their property. That's where the root cellar comes in. A root cellar is nothing more than a man-made cave, used for storing food and keeping it cool. Designs of root cellars can vary greatly, but they must all be underground. An above-ground root cellar would lose its cool air as soon as the door was opened, spoiling it's ability to keep food cold.
With this in mind, there are problems with digging a root cellar into the side of a hill, as this allows the cold air to escape easier. But this also overcomes the biggest problem with digging it into flat ground, that of drainage. A root cellar in flat ground will need some sort of drainage, or it could fill up with water. So, you need to decide which one will serve you better. Of course, where you live and the kind of terrain you have to work with will have a say in that decision too.
Of course, you could solve the problem of water getting into the root cellar by making it totally waterproof. There's a company in Europe, which is making what they are calling "underground refrigerators," but are really root cellars. Rather expensive, they are a fiberglass sphere with a molded-in stairway. Once buried, the only thing above the ground is the entryway. Being fiberglass, they are sealed against moisture, so there's no risk of them filling up with water.
You could do something similar, if you like working with fiberglass. Just realize that it's going to take a lot of fiberglass cloth or mat and a lot of resin. While building it yourself would be much cheaper than buying one, it's still going to be expensive.
To build a real root cellar, you need to dig a hole in the ground big enough to build a structure in it. The structure itself can be built out of wood, rock, brick, cinder block or even fiberglass. Where you locate it is important. You want it to be in the shade, as much as possible, so that it won't be warmed by the sun.
The root cellar itself is just a room. How big you make it depends on your needs, but something around six feet by eight feet is usually sufficient, unless you are farming and want to store food from the farm there. For a survival situation, you may want to think more like a farmer and less like a homeowner, building one that's about 10' x 12'.
In addition to the room, a stairway for access is needed for the root cellar dug into flat ground. For those in the side of the hill, you'll have to cut away a bit of the hillside to make an entryway. The whole structure should be roofed over and covered by at least a couple of feet of earth. Make sure that the roof is strong enough to support the weight of the earth, as well as anything else that might go overhead.
One final thing is needed for the root cellar, that's a means of semi-controlled airflow. I'm calling it "semi-controlled" because we want to make sure that it only allows cold air in, and that it doesn't allow cold air to escape or warm air to enter. To accomplish this, we'll use the same law of thermodynamics which is causing us to put our root cellar underground.
Basically, we want a vent pipe which enters the root cellar at floor level, but it exposed to the outside air above roof level. As the cold air won't rise up the pipe, it won't escape the root cellar; and since warmer ambient air won't go down the pipe, it won't warm the root cellar up.
Another way of making a smaller and simpler root cellar is to bury a plastic bin or old refrigerator, laying on its back, in the ground, so that the lid on the bin or the door on the fridge, is flush with the ground. While that work quite as well as a true root cellar, it's actually fairly good. Covering it with a layer of straw or something else to act as insulation (such as an old mattress) would help keep the temperature lower.
#3 Evaporative Cooling
When we were talking about using water to keep food cool, I mentioned that water is cooled by evaporation. We can put that to use in a number of different ways; creating evaporative coolers which use this principle to create a cooler environment for our food.
This idea has actually been in use for long enough that nobody really knows it's origin. But in Africa, they have an evaporative cooler for food storage, known as a Zeer Pot. This simple device consists of two clay pots, much like you'd use to plant flowers in for your front porch. They are nested one inside the other, and the space in between them is filled with sand.
In order to make a Zeer Pot, it's necessary to use unglazed pots, as it is necessary for water to be able to infuse the clay. Glazed pots will not provide any cooling whatsoever, because you won't have the evaporative action that is required for the Zeer Pot to cool.
Water is added to the sand, soaking it. This water than seeps through the clay of the two pots, infusing them with water. While the water on the inside pot doesn't do much, the water that seeps through the outside pot evaporates into the air, cooling the pot in the process. As long as there is a constant supply of water (replenishing it daily) the pot will continue to cool.
Additional cooling can be provided to the contents of the Zeer Pot by placing a thick, wet piece of fabric over the opening. Water will evaporate from the cloth as well, keeping that side of the food cool too.
In testing, food stored in a Zeer Pot stayed fresh for four times longer than comparable food, which was harvested at the same time and left out in the open. Clearly, the Zeer Pot, although primitive technology, works well for keeping fruits and vegetables fresh and edible.
This concept is so effective, that a company in India is producing a variation of it, for people who don't have electricity to use in their homes. They have created what is in all effects a micro-fridge made out of clay. The fridge is double-walled, and the space between the walls is filled with water through an opening in the top. As with the Zeer Pot, the water soaks through the clay and cools by evaporation. Another advantage is that it also provides cool water for the family to drink.
Another form of evaporative cooling can be made rather easily by taking a page from the way that swamp coolers are build. A swamp cooler, if you're not familiar with it, is an evaporative cooler, used in places where there is low humidity instead of an air conditioner. Since it doesn't have a compressor, the swamp cooler is much cheaper to operate than an air conditioner is.
The way that a swamp cooler works is that it has fiber mats in the four sides of the box. Water is pumped from a sump in the bottom of the swamp cooler to the top, where it is allowed to trickle down the mats. As it does so, some of the water evaporates, cooling the cooler. A squirrel cage blower, inside the unit, pulls air through the mat, where that air is cooled. It then pushes that air into the home for cooling.
To utilize this idea, you'll need an open utility shelf. Food can be placed on all the shelves, except the top one. A covering of similar fiber matting or of cloth needs to be made and placed over the shelves, covering the top and all four sides. This covering is going to act like the fiber mat in the swamp cooler, providing a place for the water to evaporate off of.
You'll either need to wet the cover down every few hours or set up a small pump in a tray that the shelf is sitting in, to pump water up to the top and allow it to trickle down the sides of the cover. While that would be more effective, keeping the cover soaked at all times, it would also require the use of electricity. So, that option would only work if you are producing your own electrical power, either solar or wind power.
Such a cooler, especially one using a pump to keep the covering wet, would actually keep the food quite cool, much like the Zeer Pot does. The big advantage over the Zeer Pot is sheer size. While the typical Zeer Pot has about a gallon or two of space inside it, you could actually have a fairly large evaporative cooler, by using an open-sided utility shelf.
One last point on these coolers and that is that they function better when there is more air passing over them. So if you have place where the breeze is constantly passing through, such as a passageway between a house and a separate garage, that would be an excellent place to keep the evaporative cooler, allowing it to keep your food even cooler.
#4 Don't Give up on Refrigerators
Everything I've talked about here is done with the assumption of not having electricity available. In the event of an EMP or terrorist plot to take down the grid, most people would be without electrical power. But many preppers have some electrical generating capability, whether it be from solar panels or a wind generator.
I've always advised that people try to build an alternate power system which will provide for their "critical power needs" in the face of a power outage. The refrigerator is on the list of what I call critical needs; so if you have that sort of system, you have power for your fridge.
Of course, a lot depends on the individual's financial status and their ability to build things themselves. Solar power is expensive and you need a lot of panels to produce enough electricity for it to really matter. But if you have them, then you'll probably want to keep your fridge going.
A modern, energy efficient 18 cubic foot refrigerator draws an average of 40 watts of power. That's not really all that much. But it doesn't run continually; it cycles on and off. So you'll have times when it's actually drawing much more than that, especially when the compressor first kicks on, and other times when it's not drawing anything.
You can reduce that figure even further by using a smaller refrigerator, such as the ones which people put in offices and college dorm rooms to keep drinks cold. I've run one of those off of a battery pack, proving that it doesn't draw a lot of electricity
So if you're in need of emergency refrigeration, and have some electrical power available, this might be another option to consider. While a small refrigerator won't store all the food you're used to storing, it would be enough to keep your leftovers cool till the next day, cool some drinks and keep medicines that need refrigeration from going bad. In a pinch, it would be enough.
Keeping food cool, so that it won't spoil, is an important part of preventing waste. If you don't have any means of keeping it cool, then you have to eat everything you cook, before it can go bad. You also have to can or use all produce, before it can spoil.
Simple refrigeration, using the methods shown here, will aid you in your struggle to survive, by the simple expedient of preventing food waste. Spoiled food is food you can't eat. So that's something you're definitely going to want to avid in a post-disaster time of survival.You'd probably be better off adopting more than one of these methods, using different ones for different purposes. Building a root cellar would give you a place to store produce from your garden. But that's not convenient for the kitchen. So, some form of evaporative cooling or the use of a mini-fridge, tied into your battery backup system, might be what you need in the kitchen. Together, you'll have a much more workable solution for storing your food.