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.