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Dehydrated Food vs. Freeze Dried Food

A lot of people are unsure about the differences between dehydrated foods and freeze dried foods. This page will outline their primary distinctions and advantages.

Dehydrated food is simply dried food.1 It is a technique that has been used in food preservation for thousands of years.2 Modern dehydrated food takes advantage of new technology including using airtight containers and oxygen absorbers during the packaging process, this ensures very low to non-detectable levels of oxygen in the container. Oxygen, bacteria and mold is a primary cause of food degradation over time.

Freeze dried food 3 is one of the newer advancements in food storage. Freeze drying is a multi-step process 4 that utilizes a vaccum chamber at very cold temperatures to draw out all of the moisture in the food. Freeze dried food is usually (but not always) pre-cooked food, containing multiple ingredients (variety of foods and seasoning) and will often be called an "entree" or "meal". Some freeze dried foods like fruit, vegetables or real meat are single ingredient foods.

Both types provide optimal choices for long term food storage, offering essentially the same shelf life for many of the same type of products. The real difference between these two types of food is found in these areas:

Taste and Preparation

Dehydrated foods are generally packaged without any seasoning or additional ingredients (usually). There are some exception to this, found in the mixes, soups and stews we carry. These emergency food products do contain multiple ingredients and can be used to make a complete meal without adding anything.

Many of the other products in the Rainy Day line are single ingredient dehydrated foods. For example: rice. It is just rice - the same rice that you can buy in the supermarket. The main difference is that our products are all packaged for long term storage in cans, buckets or even pouches, which makes a decided difference in terms of freshness, nutrition and shelf life versus what you would buy in the supermarket. Airtight containers are essential for a long shelf life, without this, the food would go stale in just a few months.

We also have a number of products packaged in bags. Bagged products should be put in airtight containers for long term storage, or simply used right away.

Dehydrated foods require cooking and seasoning. Cooking times vary, but most dehydrated foods are added to boiling water. You can also do "thermos cooking" by adding boiling water to a thermos, adding ingredients and letting it sit for a couple of hours. Then just forget about it - the food will cook itself. A crockpot is another simple technique for preparing dehydrated food items. This allows the food to simmer gently, fully rehydrating and mixing flavors for wonderful meals.

Stovetop cooking is easy too. Add the ingredients to boiling water and let it cook until tender. This varies from a few minutes to a hour or so, depending on the product. Whole grains and legumes, such as rice, beans and wheat take the longest, while potatoes, par-boiled rice and other products like pancake mixes are the easiest and shortest cooking time. By adding water, you're rehydrating the food back into it's original natural state before dehydration, but it's still "raw". It still needs to be cooked until tender.

Pancake mixes, bread mixes, cookie mixes, muffins, etc., are all very good and require just a little water (cold) to be ready for baking or frying. Scone mixes are an example of fried bread (Indian bread) and are very easy to prepare.

Most dehydrated food will benefit from adding seasoning. Rice doesn't taste like much until you add something to it as an example. You can use anything, dehydrated vegetables, butter, TVP (textured vegetable protein, a soy based meat substitute), real meat, potatoes, or whatever you want, and any seasoning desired, such as salt, pepper, tobasco sauce, garlic, white cream sauce, tomato sauce (virtually anything, even ketchup).

Pasta is the same; noodles / spaghetti / macaroni doesn't taste like much by itself, until they've had something added to them. Spaghetti is everyone's favorite, but it is the toppings that make it so. You can add any ingredients or topping to dehydrated foods. Seasoning is recommended simply for taste, it's not actually required. You can read more about taste by visiting our dehydrated food taste test page.

Freeze dried foods, on the other hand, are usually foods containing a multitude of ingredients and seasonings. Nothing more is needed, just a little cook time in hot water to rehydrated them to have them ready to eat (10 - 15 minutes). They are pre-seasoned, pre-cooked and pre-mixed with other ingredients, making them the fastest and easiest foods to cook.

Freeze dried foods are the easiest to prepare and tastiest foods we carry, bar none. If you don't like to cook and want great food with great taste, then freeze dried food is hands down the winner. Mountain House offers a 30+ year shelf life on both freeze dried food stored in cans and pouches, with verified testing using archived 30+ year old pouches demonstrating that these products still taste quite good despite being over 30 years old!

Mountain House has also issued a press release regarding Wise Foods (oxygen levels were 110 times higher than Mountain House!)

Mountain House Long Term Archived Pouches Taste Test


Cooking is very simple. Instructions are found on the side of every package we sell - though they are hardly necessary due to how easy it is to cook our foods! Simply measure out the amount of ingredients you wish to make (depending on the number of servings you want) and add to boiling water. Personally, I don't actually measure anything. I just scoop out a cup or two, depending on how many are eating, and add it to boiling water. If I have too much water, I can add more food, or simply drain a little water off. If I have too little water, then I merely add a bit more. Instructions, found on the side of every package we sell.

Cooking times are pretty short. Usually, 10 - 15 minutes will do it for most foods. This applies to all the freeze dried foods from all of our product lines, and many of the soups, stews and mixes from the Rainy Day food lines. Items such as biscuits, cookies, pancakes and bread mixes take a little cold water to make the dough or batter and are then baked. Indian bread (Scones) are fried on a hot frying pan for flat bread.

Other items, such as rice, beans, wheat (whole grains) take longer cooking times and can be simmered for 30 minutes to an hour or more. For these products, a pressure cooker is great, drastically shortening the cooking time required. A pressure cooker is a huge time saver and energy saver, if you don't have one, we definitely recommend one. Just add all of the ingredients into the pot and cover with water. Put on a low heat and let it cook for anywhere from 30 minutes to an hour. Even beans cook considerably faster with a pressure cooker then on the stove. Make sure you don't let the cooker run low on water, so check it occasionally until you get a feel for how they work.

Dehydrated and freeze dried foods are actually rather easy to prepare and cook. They are identical to the foods you are buying now in the supermarket. All that rice, beans, pasta and mixes you are accustomed to buying and preparing? That's what we sell, same food, lower price and much larger quantities then those little packages you're throwing away now. Our food is high quality, tasty and nutritious, packaged for long term shelf life.


Keep on hand your favorite seasonings. We sell a few seasonings, but there are many more you can use. Dehydrated food should be seasoned for best taste. The freeze dried entrees won't need any seasoning at all, unless you're one of those that drowns everything in ketchup. You can even make ketchup from our tomato powder! We keep on hand the "basic" seasonings like salt, pepper and garlic.


Freeze dried food is usually an "entree", containing multiple food items for a complete meal. Most entrees have several items included within them and you don't need to do any other cooking or adding ingredients to make a complete meal. Because it's freeze dried, you simply add hot water, or add the product to hot water and cook for about 10 minutes for this to fully rehydrate. This rehydrates the food completely and it's ready to eat!

Dehydrated foods are usually single ingredients. You can mix any dehydrated food with any other food product for a combination of tastes, textures and varieties.

Best Value

Pound for pound, and dollar for dollar, dehydrated food costs less than freeze dried food. Nothing comes close to the value of dehydrated food - not even store bought canned food, which is considerably more expensive. A single #10 can of dehydrated green beans, for example, represents 27 cans of canned green beans, which take up a whole lot of space and is mostly water and lost nutrition. Dehydrated food on the other hand, is more nutritious since none of the food has had any of the nutrition "cooked-away" during its preservation process.

Number of Servings

Every package is labeled with serving size, instructions, and preparation information. The large #10 cans (large coffee can size) will make quite a few servings depending on the product and product line. For example: a #10 can of freeze dried entrees will make 10 - 11 servings on average. A #10 can of dehydrated green beans however, contains 48 servings. The actual number of servings is found on each product detail page on our website.

Dehydrated and freeze dried foods are highly concentrated, compared to what you will find in the supermarket. There's no fancy packaging to toss out, or excess air in large boxes with a small quantity of food inside, or small serving sizes. Even our 2 person foil pouches contain a whopping amount of food when rehydrated. Our 30 day diet eating nothing but dehydrated and freeze dried food in December, 2006 demonstrated just how far this food will really go, and I couldn't finish most single servings sizes by myself.

Opened Containers

A lot of people want to know how quickly they must consume the food in an opened container. This question applies to any of the foods we sell, whether cans, buckets, or even the mylar bags or foil pouches.

We've found that if the container is left sealed (put the lid on or close up the mylar or foil bag), we can eat the food five years or more past the date it was opened. We've been eating these foods for over 20+ years now and have had many opened containers that we didn't get back into for a long time (literally years later). Keep them sealed by placing the lids back on to keep the humidity, moisture, and bugs out. When you need some food, scoop out what you need and close the lid. It's that simple.

Mountain House's position on this is a rather conservative "two weeks" to consume an opened container. Honestly, we don't know why; it has not been any sort of a problem for us to eat food that has been left open for several years. Rainy Day doesn't specify so we don't know their stated position. For us though, it has been years with no noticeable decline in taste or quality. This applies equally to both dehydrated and freeze dried foods.

Shelf Life

Most (but not all) Rainy Day products can attain shelf lives for 5 to 30 years depending on the food product. Mountain House advertises a 30 year shelf life. Store your food storage in a cold (or cool) dark place out of direct sunlight, preferably at a constant temperature. Keep it away from flooding basements or put it on pallets if you need to. Please read our shelf life page to learn more about the shelf life of our various products.

Space Requirements

Storable foods, whether freeze dried or dehydrated foods, are very compact - in fact, far more compact than canned foods or MRE's (which we do not recommend). There is no excess water or fancy packaging, no empty air spaces and giant sized boxes with tiny servings inside. An entire year supply can be fit into a 2 ft x 3 ft area, stacked 5 ft high. Or under the bed. Or in a closet. Or in the pantry. Or in the basement, or under the house. These foods are concentrated, because the water and air has been removed before packaging and there is no wasted space. A single can contains many servings, instead of 1 or 2 servings found in a can at the supermarket.

Food Security

This is a subject dear to heart. We have closely followed the issues with the global food supply for many years. Most people are utterly unaware how fragile the US food supply really is and how it can be affected by economic conditions, climate, disruptions or disasters. The mega-mergers of family owned farms and corporate giants, the declining energy supply, the fragile state of our infrastructure, and the vulnerability to things like hurricanes, pandemic, and oil prices are often misunderstood. America is the land of plenty, right?

Not always. And certainly, not forever. During times of crisis, the supermarkets are stripped bare in a matter of hours. American's used to stock food as part of their everyday preparations but have since forgotten this time honored practice. Now, everyone rushes to the store to "stock up" when the news or events frighten them into doing so, but it's actually too late then (prices are already higher and availability is uncertain). Or worse, they will wait until after a disaster and find out there is nothing left. This has happened countless times in America's history of regional disasters. Everything is sold out in mere hours and some merchants even take unscrupulous advantage of the crisis by jacking up prices sky high.

Don't be vulnerable, plan ahead. You simply never know when you are going to need to be ready. We've written much more on this subject, some of it can be found here.