For a one week trip in a dry region I need to conserve water and weight. My idea is to bring precooked "instant rice" and pulverulent mashed potatoes. I´d warm a bit of water to about 40 - 50° C and mix it with the rice or mash. Would that resemble anything edible? (I'll try at home and post the results, but hope for some thoughts and input.)

The benefits: I don´t need the power to cook a liter, warming a quarter will do. That`s 1/10 of enery and 1/4 of water for every meal. Instead of using a full fledged gas cooking device, I can bring some Esbit. For each 3 day-intervall of water self-suffiency, that saves 5 kg. What are possible downsides?

EDIT: I have been unclear about the pre-cooked rice. I mean the vacuum-packed, non-dehydrated rice they sell it in grocery stores. Usualy you´d just warm it up for 2 minutes in a microwave oven, and that´s it. But I am not sure if the warming up is for safety or taste reasons.

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    Why not use boil in the bag rice and just cool the water down after and keep it? You've probably lose the same amount as you'd use? And then no nasty side effects from re-cooked rice
    – Aravona
    Commented Apr 1, 2016 at 11:02
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    Probably a bit exotic for you to find, but if you're set on rice, have you considered buying rice flakes (available in Indian stores)? They can be stored for very long periods, and can be re-hydrated with cold or warm water, and are quite nutritious.
    – Dhara
    Commented Apr 1, 2016 at 11:29
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    Would you mind explaining this a bit better? "I don´t need the power to cook a liter, warming a quarter will do. That`s 1/10 of enery and 1/4 of water for every meal" You know you don't need to boil rice in a pot of water then drain it and throw the water away even with normal rice, right? Commented Apr 1, 2016 at 13:59
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    Hold on...keeping used rice water is not a good idea, ESPECIALLY not in the wilderness. Rice and rice water kept warm but not hot develops toxins that cause you to throw up. It's the same toxin used by doctors and pharmacists to intentionally cause vommiting when someone's eaten something they shouldn't have. Rice remains safe when it's kept hot or when refrigerated, but keeping it around in a camping environment is keeping it at an unsafe temperature.
    – Escoce
    Commented Apr 1, 2016 at 16:01
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    that misleading "boil in the bag" ! could have meant the "pour boiling water in the bag" kind of food but OP actually meant the ones where you actually throw the whole unopened bag in the water and let it heat up Commented Apr 1, 2016 at 18:12

4 Answers 4


Keep in mind that any water you are cooking with is still liquids you are intaking. A pantry full of dehydrated food is an awesome weightsaver in places were you always have water available but in a dry place you need to carry it with you. Efficiency-wise, I personally found the scout kelly-kettle type stoves ( kelly kettle + pot on top) great for boiling water while cooking another at the same time in the pot on top of the kettle, not much fuel needed. And one way to conserve the water is to rinse the cup you ate in and drink it before washing it

If you were to use the precooked rice with warm water it takes about half hour to bring it back and you still should bring it to a boil after. I know of people that just soak it for a long time and eat it as it is but I think they must be crazy.

Since from your question it seems you think you cook rice boiling, draining and throwing the water out, be aware that many kinds of rice don't work that way. If you take uncooked Jasmine rice, for example, the ratio is 1 part rice and 1 1/2 part water and all the water is absorbed by the rice (so way less than a liter, 250 ml of water will be even too much for one person). Forget Arborio or similar as they take long time to cook. Precooked rice works the same as it will absorb the water and at 1 to 1 ratio usually and faster cooking. You might want to redo your calculations then and probably find out you can expend the fuel to bring the water to a boil ;). Also Dhara gave you an excellent suggestion in the comments as there are recipes for eating the flakes raw it seems.

Then, if what you mean is the ready to eat kind that comes in a bowl or similar to cook in a microwave or stovetop, that usually involves boiling the unopened container in water for more than just a few minutes. I suppose you could reuse the same water over and over as Aravona mentioned in the comments but then that stuff needs to be in the water at high temperature and for a certain amount of time to heat up or it's like you didn't heat it at all. It's not the best option as weight saver, or the cheapest IMHO and with those you better stick to the cooking instructions.

Also consider couscous, it cooks really fast, or thin rice noodles.

For the instant mash potatoes in powder those can be made with cold water, you have to get the worst kind that have only powder with no flakes. The powdered stuff is not that great so you might want to give it a try at home (on a trail all the food is ok even if disappointing at home) and maybe add some milk powder, gravy powder and butter powder (if you can find it) and some spices to turn them from barely edible to barely passable.

I don't know your tastes in food but going with all the normal grocery store instant foods the more spices you have at hand the better because they tend to be very bland. Also remember to keep an eye on proteins, as you will have to add those too and keep in mind that instant food has less nutrition than what you would have cooking it yourself from raw.

Or you can go the MRE way, those with the self heating chemical pack, the only water needed in those is the one for the chemical reaction, you don't drink it, don't keep it and it's not in direct contact with food so can be any water you find. They are not cheap if you don't have a "direct source" and for a whole week it will be sad but covering 2 or 3 days with those might mean the weight savings you want. Or FSR for extremes, but only if you plan to be too tired to be thinking about how sad is the meal you are eating ;)

With a diet of instant rice and instant potatoes (and the military stuff) for a week you better bring some form of fiber supplements or you will cut down on bathroom breaks quite a bit ;).

  • Thank you for your detailed and excellent answer. Going with your health concerns and your mention of the value of food on the overall morale, I will plan one professional freeze-dryed meal per day. Commented Apr 4, 2016 at 14:17

Your main problem I'd say is that keeping cooked rice unrefrigerated and then not heating rice adequately can potentially cause you to become very unwell! There is even specific guidance about the reheating of rice on the NHS web site:

Can reheating rice cause food poisoning?

Yes. You can get food poisoning from eating reheated rice. However, it's not the reheating that causes the problem but the way the rice has been stored before it was reheated.

How does reheated rice cause food poisoning?

Uncooked rice can contain spores of Bacillus cereus, a bacterium that can cause food poisoning. When the rice is cooked, the spores can survive. If the rice is left standing at room temperature, the spores can grow into bacteria. These bacteria will multiply and may produce toxins (poisons) that cause vomiting or diarrhoea. The longer cooked rice is left at room temperature, the more likely it is that the bacteria or toxins could make the rice unsafe to eat.

Tips on serving rice safely

  • ideally, serve rice as soon as it has been cooked if that isn't possible, cool the rice as quickly as possible (ideally within one hour)
  • keep rice in the fridge for no more than one day until reheating
  • when you reheat any rice, always check that the dish is steaming hot all the way through
  • do not reheat rice more than once

Source NHS

So I wouldn't say this is a good idea. This is why pre cooked rice you buy from the shops is vacuum packed and refrigerated.

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    I assume that when OP says "precooked instant rice": "Instant rice, also known as minute rice, is rice that has been precooked and dehydrated so that it cooks more rapidly. ... Because it has already been cooked, all that is necessary to prepare instant rice is to simply re-hydrate it with hot water." This stuff has a long shelf life and doesn't require refrigeration, but it's not clear that 50° water would be sufficient to rehydrate it properly.
    – Pont
    Commented Apr 1, 2016 at 10:06
  • Or kill any bacteria that may be in it. Precooked rice typically has instructions to "ensure piping hot" i.e. heat to 100C to kill bacteria.
    – user2766
    Commented Apr 1, 2016 at 10:21
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    +1, but it's not your typical food poisoning. The toxins that rice develops at unsafe temps are the same as used by doctors and pharmacists to cause intentional vommitting. This isn't really food poisoning in the classical sense as you aren't ill, you are just behaving as if ill, but it can still cause major dehydration.
    – Escoce
    Commented Apr 1, 2016 at 16:02

Honestly you are better off bringing some other form of starch, such as hard tack or saltines or something similar. Take a bite of cracker, and take a sip of water and chew.

Rice and rice water, when kept at unsafe temperature develops a toxin that is used by doctors and pharmacists to induce vommitting such as when someone eats something they shouldn't have. This isn't classical food poisoning, but in the wilderness this can be a cause of serious dehydration and I don't recommend it, ESPECIALLY, since your goal is to reduce the amount of water you need to bring with you. You will be putting yourself in a very dangerous position.


If you have to carry all your water with you then you might as well use 'wet' food rather than dehydrated as it works out at the same weight in the end anyway. Pouch type meals are becoming increasingly mainstream and have the advantage of being perfectly palatable cold and straight from the packet. In cold weather you can carry them in an inside pocket of your clothing during the day so they aren't stone cold.

Personally I often like to use food which doesn't actually require any cooking at all and just use a metal mug and very simple solid fuel or alcohol stove for hot drinks.

For low fuel cooking cous-cous and noodles work much better than rice as they will rehydrate eventually even in cold water and are quick and easy enough for lunch also both seem to soak up flavours better than rice and, for my taste at least, end up giving you more palatable meals.

It is also worth considering things like unleavened bread (chapattis, roti etc), rice cake or crackers, which keep well, are light and robust enough to survive a week in a pack.

Also useful are flavoured oils, things like chilli and garlic infused oil or toasted sesame oil. These pack a lot of calories for their weight, keep well and vastly improve the flavour of hiking food. Decant them into small plastic squeezy bottles of an appropriate size for your tip and add a dash to your food. Things like chorizo and sardines or tuna in oil achieve much the same thing and add some texture and protein.

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