How to Cook With a Thermos:
A Practical Survival Cooking Method

Thermos Cooking

A common, everyday thermos bottle or jug is actually a unique piece of emergency preparedness equipment that can turn otherwise difficult-to-prepare storage foods into breakfast, lunch or dinner in an emergency situation.

Thermos cooking is not cooking on the stove and then putting the food into a thermos to keep warm, although that is an option.

But for a practical survival cooking method, cooking right in the thermos can save fuel and water.

Thermoses have been used for many years by workers to keep beverages or lunches hot; by campers to prepare easy meals; and by moms for giving their kids hot or cold lunches. So using them in a crisis seems like a no brainer.

Using a Thermos is an efficient use of water and fuel.

Because dehydrated foods are small, hard, and brittle, the thermos is a fuel efficient method of reconstituting them. They take time, heat and water—things you won't have a lot of in an emergency situation. Whole grains, dry beans, pasta, and dehydrated vegetables also require time, heat, and water to make them edible. With a little creativity and imagination, the thermos is the perfect method to use when time, heat, and water are in short supply.

For example, instead of simmering dehydrated vegetables on a camping stove for twenty minutes (the normally recommended method of reconstitution), you can heat water to almost boiling and pour it into a thermos jug over the food, cap it tightly, and go for a hike for about an hour. When you return, check to see if it's ready. If not replace the lid and soak a little longer.

The results are the same, yet you have used substantially less fuel and less water, since none of it is lost to evaporation.

TIP: Choose a thermos with a wide mouth so it’s easier to get food in and out again.

Expansion Room is a Must

Knowing the capacity of your thermos is important because dehydrated foods or whole grains and beans expand to two or three times their original size after soaking or reconstitution, so allow sufficient room for expansion.

A general rule of thumb is two parts water to one part product. Whatever the capacity of the container, divide that number by three to determine how much dehydrated food or grain you can soak in it.

If the bottle will hold 1-1/2 cups of water, then you can safely put 1/2 cup of product in it and one cup of water.

If it holds 12 cups of water when you measure it, it will accommodate 4 cups of product and 8 cups of water for reconstitution purposes. Keep in mind that this is a general rule; beans, for example, can be an exception. Some types of beans can increase in volume 3 or 4 times, not just double. When using beans in a thermos, use fewer beans until you're familiar with how much they will expand.

Be sure to use sufficient water. Too much water is better than not enough water. If the water is insufficient, the product will get wet, absorb what water is available, and that will be all. It may not be enough to make the food edible. If you use too much water, the product will absorb all it needs for full reconstitution, and you can simply drain off any unabsorbed liquid and use it as juice or stock for soups.

Using several thermoses at the same time gives you more options, particularly if you have a large family. If you decide to purchase one or two now for future use, I highly suggest choosing ones that have wide mouths. I'll tell you up front, it can take patience and time getting the cooked food out of your thermos if it is one of the small-mouthed varieties. You'll have to use a knife or long-handled spoon to help it out of the bottle. It will be inconvenient but remember, during an emergency situation, everything is going to be inconvenient. This is just one of the minor annoyances you may have to put up with in order to have warm, healthy food to eat.

  1. Measure food and water. To use your thermos for reconstitution or preparation purposes, measure your food product into the thermos bottle or jug. Add the right amount of very hot, but not boiling water. Boiling water can cause plastic thermos bottles to melt and can shatter glass-lined bottles (not sure you can even find glass-lined any more). Stainless steel is a better choice for a thermos and boiling water won't damage it.
  2. Screw the lid on tightly and shake the jug gently to stir it up. Then wait. Dehydrated food should be completely reconstituted in an hour or so. Whole grains or cracked beans take longer, maybe 8 hours or so. The smaller the chunks or kernels of food, the faster they will be done. Oatmeal or other flaked grains can be prepared in a much shorter time span than whole grains or beans. The thermos system is appropriate for pasta also; the preparation time is often no more than half an hour or so.

Camping Tip for Thermoses

Here's a bonus idea for using your thermos and picnic jugs in emergency cooking situations: Heat as large a container of water as possible while your emergency stove is in use. Fill as many thermoses as you have with hot water. Put the lids on tightly and set them aside. You will then have hot water for hot drinks throughout the day or evening without using additional fuel.

Creative Ways To Use Your Thermos

Thermos food preparation isn't limited to plain grain or a single variety of dehydrated food at a time. It can be used to prepare an entire meal — breakfast, lunch, or dinner.

Cold Foods — Make a fruit salad, chicken salad, or vegetable salad for lunch the night before. Refrigerate overnight and your lunch will still be cold by lunch the next day.

Cold Breakfast — Fill a small thermos with cold milk. Take your favorite cereal in a baggie. When you are ready to eat breakfast the next morning (maybe saving time or money on a trip), pour the cereal into the thermos and enjoy. Don't forget a spoon!

Hot Breakfast — Fill a small thermos with hot water and take your favorite flavored oatmeal in a baggie. Pour into the hot water for your morning breakfast away from home.

Dinner — Try this recipe for thermos soup. It's delicious, easy to prepare, and, if started in the morning, it's ready to eat for dinner. A little fuel is required to heat the water initially. Check out ThermosCooking.com for more great recipes.

THERMOS SOUP

  • 1-1 1/2 cups grain: any kind, any combination (try basmati rice, cracked wheat, sweet brown rice and barley, or split peas, lentils and long grain rice)
  • 1/4-1/2 Cup dehydrated onions
  • 1/4 cup bacon bits from a jar (real or imitation)
  • 1/4 cup dehydrated celery
  • 1/4 teaspoon each marjoram and thyme
  • 2-3 bay leaves
  • 1 tablespoon chicken soup base (or 3-4 bouillon cubes)
  • salt and pepper to taste

Place all ingredients in a gallon-sized thermos. Pour very hot—but not boiling—water over the ingredients to fill the jug three-fourths full (approximately eight cups). Cap tightly and shake gently. Let it sit for eight hours or so.

Prepare in a separate thermos (as these items will be ready in about 1/2 hour) and add to the other thermos the last half hour:

  • 1/4 cup dehydrated carrots
  • 1/4 cup dehydrated green beans
  • 1/2 cup dehydrated diced potatoes
  • 1/2-3/4 cup pasta

Enjoy!

Choose From Many Sizes

Thermoses or insulated jugs range in size anywhere from a one-cup child's lunch box size up to a two-gallon camping jug.

A standard one-quart thermos bottle will only hold about one cup of dry wheat kernels, while a gallon-sized or bigger camping jug will hold four or five times that much.

Purchase several sizes for different cooking needs.

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