Home dehydrating food

Imagine you could reduce the weight and size of your tent by eighty percent while it was in your boat, then when you reached camp, plump it up to its original size, weight and shape. It sounds ludicrous, yet you can perform such astounding magic with what’s often the heaviest item in expedition - food.

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At last weekend's Plas Y Brenin Paddle Expedition Symposium I found other people were interested in knowing more about this, so I've posted an updated version of an article I wrote for TGO Magazine.

A sustaining home-made tomato sauce with pasta might look unappetising, like a torn up red tissue, but it weighs little more than a hanky and fits in the palm of a hand. A delicious meal of tuna and mushrooms with rice weighs little more than the zip-lock bag it’s in. Before we hiked the Pacific Crest Trail in 2002, my partner Liz and I dried several months of supplies.

From our trials and errors, I’ve distilled a basic formula for making simple, cheap backpacking meals at home.

People have been drying food for centuries. Some buried it in hot sand, others smoked it, while in Peru they fashioned a type of crisp by air-drying potatoes. Trekkers in Nepal and Pakistan still see fruit and corn drying in the sun. The idea is for hot, dry air to drive out moisture without cooking the food. This inhibits the growth of micro organisms and has long been the easiest and cheapest method of food preservation.

Nowadays it’s considerably easier with a home dehydration machine, which is little more than a fan heater with trays stacked on top. The mesh trays allow air to rise through them, and while this is great for drying meat or fruit, backpackers will need several solid sheets called “leather sheets” to dry sauces and small items like peas and rice. There are recipe books describing techniques such as dipping, blanching and candying, with methods of drying everything from asparagus to zucchini (OK courgette - the books tend to be American). But who has the time to do that? Instead, I’ll give you a fast and efficient way of starting to make your own range of hill-meals with the minimum of fuss.

Think of this system as a savoury pick-and-mix, with two basic sauces; one is tomato, onion and sweet pepper; the other is mushroom. To these you pick-and-mix extras such as sweet corn, peas, kidney beans, lentils or tuna, and to bulk up the meal, add rice or pasta.

Basic Sauce 1: Tomato
In a large pot, sweat the onions, but do NOT use oil or butter, because fat doesn’t dry-out properly and can go rancid. When the onions are soft, add crushed fresh garlic, tinned tomatoes, finely chopped sweet pepper, tomato puree and a few herbs and cook for ten minutes or so. You can make two different basic sauces at this stage by pouring half into a second pan. To one add some pre-cooked lentils, to the other add tinned kidney beans and some chilli pepper. Simmer each until they are thick and need a spatula to spread. You now have one basic tomato-and-lentil sauce and one basic vegetarian chilli, and with more experience you might want to add other vegetables or minced lean beef or lamb to either.

Basic Sauce 2: Mushroom
You can make a proper mushroom sauce, but this is easier. Sweat onions in a large pot without oil, and when soft add a couple of cans of Campbell’s condensed mushroom soup, and some very finely chopped mushrooms. Simmer until the mushrooms soften and the sauce is thick. That’s all.

Dehydrating Sauces
While the sauces cool, work out how many portions you’ve made, because once dried it’s hard to tell and you’ll divide them up by weight. With a paper towel, wipe a tiny amount of vegetable oil onto the solid leather sheets so the sauce doesn’t stick, then set them on individual drying trays away from the dryer. Spoon the cool sauce onto a sheet and spread it thinly and evenly. Set the tray onto the dryer base, and move on the next one.

Sauces take 8-20 hours to dry depending upon their thickness and the machine. When done it’ll be what’s called a “leather”, a pliable sheet of sauce which can be peeled or picked off. A beginner’s mistake is to make the leather too thick so the outside dries and traps moisture. Tear off a little to make sure it’s dry right through with no sticky or tacky areas. We’ve yet to roll a complete leather off a tray, we tend to pick ours off in small lumps which don’t look as neat but actually make re-hydrating easier. If the leather has completely stuck to the sheet, put the tray in a freezer and try again when the sauce has frozen.

Rice and pasta
To save fuel, and so all components of a meal can cook together in one pot, avoid slow cooking rice and pasta on the expedition. You can buy decent fast-cook pasta, but fast-cook rice never tastes as good as whole-grain, so we dehydrate our own. Cook as normal, drain, spread grains on a solid sheet and dry. You can do the same with tiny pasta shapes or spaghetti.

Tuna and peas
These are useful pick-and-mix components. Boil frozen peas, cool and place on a drying sheet. Open a tin of tuna in water (not oil) and crush onto a drying sheet. Neither looks impressive when dried, as the peas shrivel and the tuna turns to dust, but once sprinkled into either basic sauce and re-hydrated their flavours come through.

Meat and fish
In Africa it’s “biltong”, to the French and Spanish it’s “char qui”, but we know dried meat as “jerky”. The list of chemicals on a packet of shop-bought stuff can turn your stomach, but a food dehydrator produces superb jerky at a fraction of the price.

All meat must be lean with fat and connective tissue removed. Fish must be cleaned of all skin, bones and blood. Flesh is easier to slice thinly when it’s semi-frozen, but must be fully defrosted before drying. Traditionally, jerky is marinated to impart flavour and to tenderise, then dried raw, but increasingly the advice is to cook it to kill all micro organisms. So before attempting to make jerky, for safety and to decide what to put in your marinade, seek out some recipes in books or online. And don’t try to take meat or fish into the USA.

Dehydrated food must be kept in airtight containers away from moisture. We rip up the sauce leather into a bowl, then divide it into portions by weight, before sealing it immediately in zip lock bags. Roll them to expel as much air as possible before sealing. Thicker, more expensive bags are worth using so the sauce can be re-hydrated in the bag.

On the sea
A couple of hours before you plan to stop for your meal, start re-hydrating the food. If you’ve used thick zip-lock bags, you can top one up with water, reseal and put it inside your cook-pot, just in case it leaks. Try to keep the pot level so as you paddle the food will be shaken and slowly suck up water. Alternatively, put it in a wide-mouthed water bottle. At meal-time, re-heat the rice or pasta together with the sauce. We also stir-in a little olive oil to add taste and calories.

It can sound like a lot of fuss, but if you treat it as part of the planning process it can be fun way to spend a wet weekend. If you regularly escape to the hills, shop-bought backpacking food can become boring and prohibitively expensive. With a home dehydrator, the cost is all at the start. You’ll quickly master these basics and start to experiment. You’ll discover dried apple slices are delicious, mangos magnificent, while fruit smoothie leathers are clinically addictive. In fact, you’ll want to go backpacking even more often, if only for the food. When was the last time you ripped open some freeze dried fodder and thought that?

Picking a dehydrator
In Britain we’re not overwhelmed with choice, but ours is by EziDri. Choose a machine 500-1000 watts for faster, more efficient drying, with a fan to blow air up from the base. More sophisticated models give control fan speed and precise control of temperature. Backpackers and kayakers mainly dry sauces, so ensure you can buy extra solid “leather sheets” since you may need more than the two which usually come as standard, although you can cut your own from baking paper using the original sheets as templates. If you’re planning to dry huge quantities of food for expeditions, you might want to check the sheets fit in a dishwasher. The definitive text is “Mary Bell's Complete Dehydrator Cookbook”.

I'm going to have to persuade Liz to share her knowledge in a Podcast.


Michael said...

Thanks for a great post, Simon. I'm a dehydrator fan as well and dry up (down?) several recipes to take when I head out paddling. Beats the somewhat expensive commercial stuff hands-down and well worth the effort. The hint I take from the commercial stuff is to package complete meals in a single vacuum bag (do you have one of these?). Then it's just grab the bag, and the meals nearly done!

Unknown said...

Great post Simon. I have been trying to find good info on the net on dehydrating and there isn't much. Would appreciate more! Here's a link to a post on my blog on your article:

Anonymous said...

Wow, I had no idea!
Wasn't quite sure whether the dehydrated food needs soaking or boiling or both. Or does it depend on the food type?

Simon Willis said...

Hi Michael - we don't have a vacuum bag because we don't think it would save much space in each pack or add much to the shelf life. In the freezer, this stuff keeps ages, and on the trail stayed fine for six months. The secret is not to use ANY fat as it goes rancid. The bags roll really small, but I know some people link the shrink-wrap thing. W
e keep the sauce element separate from the carbo element (rice/pasta/noodles) because Liz likes the flexibility this gives when deciding what she fancies eating.

Matt - thanks for the link on your blog and I've commented there about fishing.

Liz - once the sauce or rice is cooked and dried, then you could eat it as it is. You could chew on the sauce "leather" like tomato jerky!

When you add water it starts to re-absorb, so if you do this in the morning, then by evening you'll have a cold tomato sauce in your bag (or better, tub with lid) which you'll just have to warm up. Rice/pasta ditto.

If you added the water just an hour (or less) before you eat, then you'll need to bring the water to the boil to increase the rate at which the leather absorbs the water. Remember, it does not actually need cooking - you did that weeks ago.

It comes easily with practice. Mind you, the tuna is tricky to get right first time. I remember one hideous meal on the GR20 in Corsica, but after that (my) Liz quickly mastered it.

She's 'head of expedition food' around here, I just write about it and eat it.

Unknown said...

Simon - Thanks so much for posting this information about your dehydrating successes. My husband and i have only just started using our dehydrator for backpacking (the exact same ezidri as yours!) and so i've been searching the net for inspiration. One of our staples was tuna before we had the dehydrator, so i'm glad to finally see that someone has dehydrated it with success. That mushroom sauce sounds delicious and i'm going to go and try it tonight for our next trip in a couple of weeks. Thanks again for all the information, and please post more good ideas if you have some for those of us who are dehydrating novices!

Simon Willis said...

Thanks for the kind words Stephanie. Liz is really the expert in our house, and we've done less of it since we've been kayaking rather than backpacking. We (she) was a novice until she'd deyhdrated several months of dinners for our PCT hike! Keep experimenting and you won't go wrong.

emily said...

On my second year of dehydrating for trips and I am looking forward to getting more experimental. I have been trying to find out somewhere online - how long deydrated tuna will last for, or how to preserve it.
Any insight to this?
With thanks.

Simon Willis said...

Hi Emily

I'll reply on the basis that I'm speaking from our experience as back packers with strong stomachs, not chefs or environmental health scientists!

Liz reckoned that the more she deyhdrated tinned tuna, the more it flaked. When it was cooked, it ended up being what we called 'tuna mush' (sometimes 'cat-food mush'!). It flavoured the rice and peas, but wasn't really recognisable as tuna. OK on the trail, not on the plate at home.

It kept for over six months like this, which was good in resupply boxes. Stuff she dehydrated in Jan we were still eating in Sep.

Liz thought if she dehydrated the tuns less it might hold its consistencey better but might go off quicker, so she didn't experiment.

I hope that's a useful explanation of what we did.

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Jan said...

Thanks Simon for your instructions,
I used my dehydrator for the first time and did tuna. should I store it in zip lock freezer bags in the freezer? How long should it keep for? Looking forward to trying your sauce recipes!

Cheers, Jan

Lissa said...

Wow! That's very testy. I chocked above 2 recipes. When I show this post to my husband he want to eat these.

Have you any other recipe?

Thanks for this.

Simon Willis said...

Hi Lissa - all we have is here, but use these as a basis from which to develop your own. There ar ea lot more books out there now too compared to when I wrote this post, more than ten years ago!

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