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Freeze-drying seems to be the perfect method for food preservation to take on trips to the outdoors: is the most lightweight food can be, can be shipped around the world easily, the majority of nutritional value is retained, no preservatives are needed and most important, no energy, no electricity is required to keep it good, and it can last years. Just add water and mix to get kind of a smoothie. Seemingly it should be vastly superior to any other method of food preservation.

Why are other methods still much more popular, and easier to buy such preserved foods:

  • canning
  • soaking in solutions of large amounts of sugar or salt
  • high-heat drying
  • freezing
  • fermentation

All these above methods seem not as good as freeze-drying, yet they are all much more popular on the market, and freeze-dried food seems to be quite a rare and obscure thing to buy.

There are some freeze-dried powdered fruits and vegetables on the market, but few and far in between, there is infinitely more vendors selling canned fruits and vegetables, which are heavy, don't last as long, and are often loaded with added sugar.

It's even more rare to find freeze-dried meat or fish for sale, but you can buy canned sardine almost everywhere. Canned food seems to be the most popular preserved food to take on hiking trips without cooking facilities.

Freeze-dried milk is kinda available, but also mostly for speciality milk like camel milk, normal cow milk is mostly heat spray dried, which not only doesn't have as much water removed so it doesn't last as long, but also the heat used damages some vitamins, so freeze-dried would be more nutritious and healthy.

You can buy an expensive freeze-drier and do it yourself at home, but given all the amazing benefits of freeze-dried foods, and almost no difference compared to fresh when making a smoothie, I find it strange commercial-made freeze-dried food is relatively rare to find for sale.

One might say that the canned version more resembles the original fruit or vegetable, but blenders and smoothies are very popular, so why not freeze-dried food?

The high cost of freeze-drying and thus the final price of the food being too high could be the reason, but there a lot of food intended as pet food sold freeze-dried. One usually have a higher acceptable price for food for their pets then themselves, so if the economy works for pet food, it should work for human food too. Actually the majority of freeze-dried food for sale online is pet food (although some of it could be fine to eat as humans too).

What is wrong with freeze-dried food, what is the reason it is not much more popular then it is, resulting in poor choice and very small amount of vendors selling it?

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    Probably a combination of being unappetising, being expensive, and people generally not going away for longer than a few days. – Tomas By Jul 31 at 17:15
  • @TomasBy I've eaten a lot of freeze-dried beef liver powder, which is one of the few freeze-dried meats you can buy, and it is great. I mix it with ghee in a small cup and eat with a spoon like a paste. Very easy to prepare and tasty. I would like to buy other meat, not just liver in that form, but can't find any. I understand fats is one of the few things that doesn't freeze-dry well, so fatty cuts of meat might not be available, but why I can't find lean cuts of grass-fed beef, freeze-dried, powdered? – yannn Jul 31 at 17:17
  • Maybe it's a regional thing. Here in Europe there are lots of freeze-dried meals in outdoors shops etc. I suspect you might not be able to tell the difference between decent beef and liver once it has been freeze-dried and rehydrated. – Tomas By Jul 31 at 17:22
  • @TomasBy There is quite some freeze-dried meals for sale online too, but its all not pure beef, but meals, which mean it has some flavoring added, every freeze-dried ground beef for sale I found has "beef, natural flavors, salt" in ingredients. I don't want that, I want pure beef. Oh, and most of it is cooked. And from an unknown, questionable source. The beef liver I was eating was from 100% grass-fed New Zealand beef, nothing added, and it was raw, uncooked. But you can't eat too much liver, as you will get retinol poisoning, as polar explorers got from bear liver. – yannn Jul 31 at 17:31
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    Dried meat is much better, eg Jerky. – Tomas By Jul 31 at 17:51
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The answer is that it is very expensive to make compared to other forms of preservation, especially in the home. Canning can be done at home with nothing more than jars, lids, water and an oven. Smoking you need a fire and something to hold the meat. Freezing, you need a source of cold (which we usually didn't have until very recently in human history). Drying can be done at low or high heat, so you can use a fire, or even lay it out in the sun if your climate is warm and dry enough.

To freeze-dry you need both a vacuum unit and a heavy-duty refrigeration unit in done device. Freeze-drying is usually done by lowering the temperature below the triple-point and then lowering the pressure so that the ice formed sublimates. This is a very slow process for solid materials such as meats and vegetables, because removing enough of the water out of a lump of meat is difficult, relying on diffusion (in the order of micrometers/hour). For liquid formulations such as used in vaccines and similar materials it is much faster because the liquid can be spread out over the surface into a thin layer allowing the ice to sublimate rapidly.

Additional issues involve rehydration - this is slow for most meats and often results in unpalatable food that is difficult to eat (chewy) and is not particularly tasty. Vegetables and fruit that have been freeze-dried are much better (in my opinion) and can often be eaten in the freeze-dried state or rehydrated.

In my country (NZ) the majority of freeze-dried food is sold as food for hikers and hunters, it is relatively expensive per meal (~$8-12 per person/meal). It is generally sold as a pre-packaged meal designed to look like your average meal - some visible carbohydrates, some vegetables and often some strips of meat. It is not usually sold as a powder suitable for turning into a smoothie. In my understanding most vegetables might be suitable for this form of preparation, but most meats are not because of the structure of the myosin fibers in the muscle tissue and the connective tissues will not form powders, no matter how much they are dried (this is why they used to be used for things like bow-strings). Liver and sweet-breads might be some exceptions to this as they are much more homogenous in structure and don't contain much if any connective tissue.

Pet-food on the other hand can be lower quality and the pets tend to not care (as far as we can tell) about taste and texture so much as people do. Pet foods can also be manufactured to lower safety standards than foods for human consumption, these combined make it more affordable for the companies to freeze-dry pet foods.

Dairy products need to be heat-treated before or during the drying process to kill any contaminating micro-organisms. This is a process called Pasteurization, and is performed because milk can carry things like Mycobacteria and Listeria. It is cheaper and easier to spray-pasterize into a powder than it is to freeze-dry. In fact I think in most of the western world at least, that most milk is sray-pasteurized and then re-consitituted to make the 2% (skim), 4% (regular) etc. milk that is bought in many shops.

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  • Thank you. The most interesting part is actually about the meat myosin fibers and inability to form powders. As there are actually some available freeze-dried vegetable and fruit powders, there are liver powders, so I wondered why not muscle meat. Regarding pasteurization it's only "needed" in the US and a few other countries, in most of the world unpasteurized milk is legal and in some quite common, like France, Germany, Austria. There are actually available unpasteurized freeze-dried milk colostrum powders from Switzerland, very expensive. Seems all US-made milk colostrum is pasteurized. – yannn Aug 1 at 4:36
  • @yannn Myosin fibers are essentially long-chain proteins - think of a muscle as lots of long cells (as long as the muscle) that are largely made up of bundles of the myosin. Pasteurization is largely about lengthening shelf-life and public health, so most of the milk in Europe is also pasteurized. Yes you can get unpasteurized commonly, but it is a big vector for bacterial illnesses. Cheese making kills off a lot of the bugs that grow in raw milk, so this is a way to preserve the milk. – bob1 Aug 1 at 9:36
  • @yannn Colostrum is the first milk mammals make after giving birth. It is quite different in composition to regular milk and contains a bunch of antibodies from the mother as well as hormones. It is only produced for a few days after birth - that's why it is expensive. Pasteurization might affect the colostrum composition, but I have no knowledge around it at all. Spray-dried milk is cheap and easy to produce, and conserves most of the properties of milk so I'm not surprised that freeze-dried is not common. – bob1 Aug 1 at 9:41
  • I drink only unpasteurized milk, and have done so both in Europe, Asia and Africa. Big vector for bacterial illnesses... only if you don't keep proper hygiene when milking. Pasteurization affects the composition of any milk, colostrum or regular too. It severely reduces some vitamins and destroys enzymes like phosphatase, and causes certain carrier proteins which carry vitamins to be damaged and not fulfill their role. – yannn Aug 1 at 11:33

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