Propane is an easy fuel to store for emergencies because it has an indefinite shelf life. There are, however, critically important safety precautions to keep in mind.

Twenty-pound propane cylinders have a pressure relief valve permitting fuel to escape as it expands with temperature changes. These cylinders should always be stored outside and never in a garage, shed or other enclosed space. Even when storing cylinders outside, they should be stored in a place where propane could not be trapped in a partially enclosed patio or a window well. Propane will pool on the floor or the ground and will explode with a source of ignition, or even a spark from turning on a light or flashlight, or using a cellphone.

Check with your local fire authorities for legal limits on the amount of propane you can store on your property. Failure to follow their recommendations endangers your life, the lives of your neighbors and any firefighters who may come to your residence in the event of a fire.

When storing any fuel around your home, always check your insurance policy, rental contract, building regulations and any applicable city or county ordinances.

Never use a propane device intended for outdoor use inside. This includes camp stoves and grills, which emit a large amount of deadly carbon monoxide as the propane is burned. Lives have been lost from using these devices indoors.

Cooking with a haybox saves propane

This idea comes from World War II when a pot of food was heated to boiling, then placed inside a box insulated with hay to finish cooking. A "haybox" can also be made with a cooler and a blanket wadded up inside. Make sure the cooler is at least 1 inch larger than your pot on all sides to prevent the cooler from melting. Or use a large cardboard box lined with flannel, heavy fleece or several layers of newspaper and filled with shredded paper, sawdust or some other insulating material.

Make a nest in the blanket or insulation for the pan you will use. Bring food to boil in pan and simmer, covered, for three minutes. Place the covered pan in the cooler or box, cover it with a pillow or folded blanket that fills up the entire remaining space and put on the lid, trapping the heat inside. Cooking this way will save propane as food continues to cook without the continuous use of fuel.

Haybox cooking requires a little advance planning. Food takes four times longer than the recommended recipe time to cook. For example, if your recipe normally takes 30 minutes to cook, it would need to cook in a haybox for two hours. The only exception is long-grain rice, which normally cooks in 20 minutes and takes only one hour in a haybox. Note that this method of cooking can be safely used for meals using food that is cut up. It has not been tested for cooking whole roasts or chickens.

After the food is removed, leave your haybox open for moisture to evaporate before storing it.

It is important to add enough insulation in the box to keep food at a safe 140 degrees, which is the restaurant standard for food safety. Add enough insulation for food to safely cook for four to six hours, which allows enough cooking time for anything requiring one to one and one-half hours. You choose how long you want to cook with your haybox. Be aware that cooking dry beans that are soaked will require four to six hours with this cooking method.

If your haybox has been stored in a cold garage, bring it to room temperature before using it.

Test your haybox

Fill the pan you will use with water to the level of the smallest recipe you would ever cook. Bring the water to boil in the covered pan, simmer for three minutes and place the hot pan and lid directly in your insulated container. After the desired length of cooking time, remove the lid and the top insulation and test the water temperature. The temperature should be at least 140 degrees. If it is not, add more insulation and run the experiment again. Once you’ve tested your haybox, you will never have to check it again as long as you use the same materials in it.

Test your thermometer for accuracy

Water boils at a different temperature depending on your altitude. Determine your altitude and the temperature at which water boils at that altitude.

Altitude Boiling Points

Sea Level: 212 degrees

1,000 feet: 210 degrees

2,000 feet: 208.4 degrees

3,000 feet: 206.6 degrees

4,000 feet: 204.8 degrees

5,000 feet: 203 degrees

7,500 feet: 198.4 degrees

10,000 feet: 194 degrees

Place your thermometer in a pot of boiling water for two minutes. If it registers higher than the temperature given above for your altitude, add the difference to 140 degrees for the minimum temperature you must maintain in your haybox. If it registers lower, subtract the difference from 140 degrees.

A haybox is not only for use in emergencies. It’s fun to make something, place it in a haybox cooler and pack it in the car to cook when you travel. You can arrive at a family gathering or some other destination and, to the amazement of everyone, have something delicious all ready to serve.

Leslie Probert, a graduate in home economics from Brigham Young University, has been a popular speaker and is coauthor of "Emergency Food Storage in a Nutshell, 3rd Edition" with over 400 fast, creative recipes. E-mail: foodstoragechick@gmail.com