While most refrigerators are designed to keep things cool, there's also a lot of use around the homestead for one that keeps things warm. Here's a description of what a "warmerator" is useful for, as well as info on how to make one of your own.
The completed Warmerator
The high digestibility of goat's milk is good, but the trade off is that it has a very short shelf-life. One way to keep the "bad bacteria" from attacking your milk, is to go ahead and convert it into yogurt. It's really very easy; all you do is add some culture (good bacteria) to the milk and keep it at the right temperature for the right length of time. That's where the warmerator comes in; it makes culturing yogurt almost too easy.
Yogurt is great for breakfast, and it works really well as a tasty base for salad dressings, but there are other important uses for yogurt around the homestead, too. One way yogurt helps the body is by "predigesting" lactose, otherwise known as "milk sugar." That's why many people who are lactose intolerant are usually able to consume yogurt. If you're serious about producing your own sustainable diet, then milk products have an important role to play. Using a yogurt culture to pre-digest the lactose can make the difference between a diet that works and a diet that doesn't.
Another key way that yogurt is good for you is because it stocks your digestion system with lots of good bacteria. With lots of good bugs in your system, there's little room for bad bugs to get established and make you sick. Yogurt is a healthful food in and of itself, but it also has a prophylatic role in helping protect you from intestinal problems caused by bacteria in the food you eat. For folks with a compromised immune system, yogurt can play a key role as their first line of defense.
The poultry thermostat and the circulation fan
When we're working with "at risk" calves, lambs or goat kids, we use this "trick" to help keep their systems up and running while we're waiting for their immune systems to come online. We fortify their milk bottles with a dash of Probius (tm), a product that contains the bacteria that rumenants use in their multiple stomachs (their rumen) to digest grass.
As the bottles sit in the warmerator, the good bacteria multiply and six hours later, when the calve gets its milk, it also gets a substantial dose of good bacteria. This technique is also a time saver since you don't have to heat the bottles before feeding them - they're already up to body temperature from sitting in the warmerator.
Another way that yogurt is used is in the production of homemade ice cream. If you use straight milk, the lactose causes you another kind of problem. As the milk mixture cools, the lactose starts to percipitate out of the milk. This creates texture problems because both because the lactose crystals themselves are gritty, and also because the lactose crystals serve as "seeds" for the formation of ice crystals. By making the fresh milk into yogurt first, you get a much smoother, more mellow product.
The warmerator is useful for non-food stuff too. No homestead operation is complete without homemade soap. Making your own soap isn't hard to do; the tricky part involves getting a consistent product. All soap is made from the reaction of lye and fat. The key challenge is to get your ingredients accurately measured so that you mix the right about of soap with the right amout of lye. Too little lye, and you'll get greasy soap. Too much lye, and you'll have the alkaline soap that tends to take off more than just the dirt.
The temperature control knob and the power switch
Once you've got the right amount of ingredients, the next challenge involves getting the two materials to blend up into a "mayonaise" like mixture. In soap lingo, this is called "getting the soap to trace"
The trick there is to insure that all the ingredients are at the right temperature before you start to mix, and that's where the warmerator comes in. By measuring out the ingredients beforehand, and storing them in the warmerator, they're all at the same temperature and ready to mix when you are. It may not seem like a big deal, but it's one of those subtle things that can make the work go easy if you do it right, or make it go hard if you don't.
Personally, I like the easy way.
Closeup of the poultry thermostat
The first thing to do is find a dead refrigerator that's the right size. The most critical factor is that it needs to have a good door seal. Beyond that, most any old fridge will work.
You'll want to remove the freezer unit; and depending on your local laws, you may want to visit your local refrigerator repair shop to either have them suck the refrigerant gas out of your fridge, or buy a dead fridge that's already been emptied.
Once the fridge is stripped, you'll want to drill a hole through the side for the wires. I used a 9/16 inch drill bit, and then filed it out so that it would accept a length of 1/2 inch pipe. I found a washer big enough to fit around the pipe, and used that as a spacer between the side of the fridge and the electrical switch box.
The next steps involve mounting a poultry thermostat (available through most feed stores), a fan from an old computer and a light socket.
Power switch with an indicator light
I like to use an on/off switch that has a pilot light. That way I can tell if the warmerator is running without having to open the door.
I also like to use an extention cord for a power cord since they're about the cheapest way to go. Just get a 10' three prong extention cord, and cut off the female end.
There are two circuits involved in the warmerator. The first involves the fan. It needs to be running when ever the warmerator is in operation, so wire it so that when the switch is on, the fan's running.
The other circuit is a bit more complex. Run a wire pair (one "hot" and one neutral) from the switch to the thermostat. Cut the hot wire and attach each end of the newly cut wire to the wires coming off the micro switch in the thermostat. Then continue to run the wire pair up to the light socket. This way, when ever the microswitch opens, it'll turn off the light bulb.
Well, that's about all there is to it. If you go ahead and make your own warmerator, I think you'll find that it's a very good thing to have around the homestead. It might even get you to thinking about converting another old fridge into a dehydrator.