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General => General Chat => Topic started by: Rich.H on June 16, 2014

Title: Tests with drying food
Post by: Rich.H on June 16, 2014
Bugger had me a nice well thought out piece of writing done then a fuse blows and kills everything, so onwards and sod the writing aspect.

Got tired of trying to justify the price of some of the brand bought dried meals you can get as at around £6 for a main meal they are just crazy. Added to this is the fact they are a business and as such I'm skeptical about the nutrition claims they make. I can't see how they are not actually using similar processed food as most supermarket quick meals etc.

So I have recently looked into the various ways of making your own dried meals and the method that gave me the best weight/cost/convenience factor was simple home dehydration. Doesn't work with everything but things like stews, curry, bolognese are just fine and give plenty of variety.

I started with a simple enough portion of a shepherd's pie as I wanted to see how well home made mash works when I know there is a perfect instant solution. The weights for everything are as follows.

Starting weights.
Mince, carrots, & gravy part = 620g
Mash part = 630g

Finish weights.
Mince, carrots, & gravy part =150g
Mash part =140g

These are rounded weights for ease and the finish weight includes the mylar bags. But I still get a total weight saving of 960g. This is handy too as it is just under 500ml of water lost from each part and so quick and simple to know how much to boil for use. I've bought mylar bags mainly as they give a light weight simply eating platform. The theory behind them being you get a good rolling boil of the same amount of water as lost during drying. Water being a nice substance has a density of 1g per 1ml, so you can do a straight conversion for weight lost. Once the water is at a good rolling boil add it to the bag of dried food, fold the bag down and leave to sit for 15-20 minutes. This should rehydrate the food ready to eat, and leave no messing about with pots trying to cook it up.

If I were heading out on a nice gently camp with lots of gear and a big fire I would probably just throw stuff into mess tins and use them as a stewing pot. However I am aiming to use this method with a new GSI cook set that consists of a single 600ml pot, so it will be a case of boil water and add it to food and keep the pot free for use at all times.

So onto a cost comparison. My method cost me around £8 (a very generous guess) for both the food and the electricity to make. This produces me 5 portions of just over 1200g of food for each portion. So £1.60 total cost for each meal. Using current site prices Cotswold sell a Mountain House main meal for £5.50, I think that is about the same as pretty much any retailer.
That is a total dried weight of 100g, compared to my dried weight of 290g. Having seen and handled enough retail dried food in my life I am willing to argue they do not have a near 3x more effective weight reduction method. Thus the main mean for one of these must be far less than 1200g when it is rehydrated for eating. If anyone has one of these types of meal and wishes to get it make up and weight it, I would love to know just how much food there is there. For now I'm going to argue that I am making up a meal that is 1.5 times more than a retail product.

So doing the math we have a retail product:

£5.50 per 100g dried
+ £2.25 for the added 50% I think my meal contains in food weight.
Giving a total of £7.75 for each full sized main meal, compared to my own £1.60 per meal. Thus I am getting almost a ratio of nearly 5:1 on food for cash. In addition I know exactly what goes into the food, I can tailor it for any specific task or any dietary requirement. Most importantly though I know before I even put the packet into my pack that I have a meal I will enjoy eating, I find nothing worse than being out on a hill cold and wet just to discover the packet I have purchased has a taste level on par with a pot noodle, it can be a real morale killer.

I haven't yet tested how well these hydrate but will be doing so today, for now here are some pictures on the basic before and after process.
Title: Re: Tests with drying food
Post by: Rich.H on June 16, 2014
Forgot to add this one with the bags.
Title: Re: Tests with drying food
Post by: Fred on June 16, 2014
Thankyou for sharing this with us.
I agree that the specialist outdoor products are relatively expensive but I just go for the cheap handy option of supermarket dried pasta meals, rice or couscous.
Do you have a special dehydrating machine or can this be done with normal household cooking equipment?
How long do you expect your meals to keep for?

Fred
Title: Re: Tests with drying food
Post by: Rich.H on June 16, 2014
Thankyou for sharing this with us.
I agree that the specialist outdoor products are relatively expensive but I just go for the cheap handy option of supermarket dried pasta meals, rice or couscous.
Do you have a special dehydrating machine or can this be done with normal household cooking equipment?
How long do you expect your meals to keep for?

Fred

I use a bottom supplied home dehydrator, it cost around £40 and you can spend far more than that on other types. Generally you get bottom fed heat, top fed heat, and rear fed heat. From my own research I am of the opinion that that list is also from worst to best in how well they perform.

You can get by with using a cooker at it's lowest temperature with the door left slightly open, or construct your own device that involves fans and incandescent bulbs. But I found all of these options just too fiddly and inefficient for my own use. Retail bought dehydrators have the ability to dry a food item at a temperature range of 10-70 degrees for time periods up to 24 hours happily. This lets you have far better control of things and it becomes more of a setup and leave process.

As to the time food keeps it comes down to the content, generally if your food has a high fat content it will start to spoil quicker as the fat simply does not dehydrate very well, this can be felt with my dried mince as it left a greasy feel on my hands. Generally things that are dairy based or high in other fats are deemed unsuitable for long term storage. But I think long term storage is meant as a month or more, in addition you can do a few things to prolong that time such as vacuum sealing and storing in a freezer. I generally intend to be making food that will be used in around two weeks tops so I don't worry about long term and instead just make what I like the most.
Title: Re: Tests with drying food
Post by: Fred on June 16, 2014
I like the idea of doing a batch of food that would last for a season, which is why I asked about the storage life. I had experimented with a cheap vacuum sealer but it was hopeless. The bags would re-inflate over time, it just couldn't be relied on.

fred
Title: Re: Tests with drying food
Post by: t18con on June 17, 2014
only a suggestion here, but have you considered going into "prepper" type sites to see what way they do it?
Title: Re: Tests with drying food
Post by: Rich.H on June 17, 2014
only a suggestion here, but have you considered going into "prepper" type sites to see what way they do it?

I started out looking there but found better info in places that were more geared towards self sufficient folks. I found many of the prepper/survivalist types were of a mindset that they were able to outlast anyone etc but gave little thought to that actual food itself. The self sufficient type folks were of the opposite in that they were after methods that ensured they got an end product that was both tasty and healthy.

Well gave the first two bags a test run and glad I did as it really didn't go very well. The biggest problem was the mash spuds, and this was my fault as I failed to take into account how badly lumps of dried spud rock will take up water. No wonder the instant stuff is in a powder form ???. I opened up the second spud bag and put it through a blender and then broke out the mortar & pestle, but I just couldn't get a fine power. This became apparent once I added water, it looked and smelled like perfect mash but on tasting you can feel lots of small grains in the mash. If I were to do this properly it would require buying a blender that was capable of grinding powder or something along the lines of a heavy duty coffee grinder. That is an expense beyond my desires so I think for potatoes the easiest and most cost effective way is just use the instant flakes from a shop.

The mince part however worked quite well, I did discover the bags I have bought are woefully undersized for the task as I could not get a proper roll down seal once water was added. This meant putting the filled bag into a pot with water and heating for around 10 minutes longer than the 20 minutes it had already sat for. I think once I get bigger bags and things have more room to bounce around along with a good seal at the top then the process will be smoother. Oddly the amount of water needed is also a little off, no doubt if I wanted things like carrots to spring to full size then the water weight amount would work perfectly. However I think this would take too long to be practical when camped out, as it stands they are perfectly tasty just on the small side. This meant I did have quite a lot of excess water in the bag which made for a very watery gravy that was more like a stew. I imagine other foods would take up the same amount of water they gave out in good time but it would be a matter of trial and error to get a good accurate list.
Title: Re: Tests with drying food
Post by: RedLeader on June 18, 2014
This is brilliant, thanks for the info.

What exact brand of dehydrator are you using and would going with pasta solve your mash issues?
Title: Re: Tests with drying food
Post by: Rich.H on June 18, 2014
This is brilliant, thanks for the info.

What exact brand of dehydrator are you using and would going with pasta solve your mash issues?

Here is the one I have at the moment http://www.amazon.co.uk/Andrew-James-Dehydrator-Adjustable-Temperature/dp/B009DIFMXK/ref=sr_1_2?ie=UTF8&qid=1403110555&sr=8-2&keywords=dehydrator (http://www.amazon.co.uk/Andrew-James-Dehydrator-Adjustable-Temperature/dp/B009DIFMXK/ref=sr_1_2?ie=UTF8&qid=1403110555&sr=8-2&keywords=dehydrator). However I may well pull some parts out of it to make up a rear heating unit as you tend to get a move even heat spread.

Pasta probably would work better but then I wanted to give this a go as ideally I would like a fairly large range of food types I can take should the desire arise.
Title: Re: Tests with drying food
Post by: KrazyKat on June 18, 2014
 :-X
Title: Re: Tests with drying food
Post by: Matthew on June 24, 2014
Can you post links to the bags and the heat sealer please, a few of us had been toying with a similar idea.

Matthew
Title: Re: Tests with drying food
Post by: Rich.H on June 24, 2014
http://www.fresherpack.co.uk/sections/11/foil_bags___mylar_bags/ (http://www.fresherpack.co.uk/sections/11/foil_bags___mylar_bags/)
Title: Re: Tests with drying food
Post by: RedLeader on June 26, 2014
The heat sealer seems very expensive at £89 or so.


http://www.fresherpack.co.uk/sections/11/foil_bags___mylar_bags/ (http://www.fresherpack.co.uk/sections/11/foil_bags___mylar_bags/)
Title: Re: Tests with drying food
Post by: Rich.H on June 26, 2014
Don't worry about heat sealers, just use an ordinary iron. All you need is a flan surface that expels a large amount of heat. You could probably do it with any old lump of flat steel and a blowtorch if you really wanted.
Title: Re: Tests with drying food
Post by: RedLeader on June 26, 2014
Genius, that's a huge saving. Though getting the iron out might cause some panic in the house, would be quite the break with tradition ;)

Don't worry about heat sealers, just use an ordinary iron. All you need is a flan surface that expels a large amount of heat. You could probably do it with any old lump of flat steel and a blowtorch if you really wanted.
Title: Re: Tests with drying food
Post by: Rich.H on June 26, 2014
Genius, that's a huge saving. Though getting the iron out might cause some panic in the house, would be quite the break with tradition ;)

Don't worry about heat sealers, just use an ordinary iron. All you need is a flan surface that expels a large amount of heat. You could probably do it with any old lump of flat steel and a blowtorch if you really wanted.

Just be sure to do all sealing around 2am then the boss doesn't see it. As long as she doesn't realise you know how it operates you should be safe enough to never get asked to use it.  8)
Title: Re: Tests with drying food
Post by: Rich.H on July 03, 2014
Ok so round 2 on this venture and gone for a pasta bolognese, steps as follows.

1. Made the bolognese as per usual with one change. I browned off the mince in a separate pan then placed it into a sieve, followed this by pouring over 2 kettles worth of boiling water so as to wash off any excess fat. I noticed with the shepards pie mince when rehydrating the fat split and floated on the gravy/water.

2. Placed a good size portion of pasta in a tub then ladled an equally good sized amount of bolognese over the top. Left this to cool then covered and left over night. This helps most of the sauce to be absorbed otherwise you get a runny mess in your dehydrator.

3. Spread out everything over the dehydrator trays and left for just under 24 hours on 70 degrees.

The original start weight for this was around 900g and my finish dried weight was around 250g. Not quite as much of a drop as I had hoped but still significant pack weight savings. Due to my mylar bag sizes I split the batch into 3 bags. This gave around 212g of water needed for each bag. I learned last time that the exact amount of water was slightly too much and so played things safe by using 200g. Got a good rolling boil going and poured it into a bag. Again from last time I learned that you don't need to do a huge seal for the bags as you loose it all when cutting open. So I only made a tiny strip of seal and instead of tearing I used a knife to cut a slot at the top, this meant I still had the full bag height. Once the water was added I rolled down the top as tightly as possible and left it.

Here is where I think this style of cooking needs a little more preparation than other methods. If you setup your camp then start making dinner you are going to be left waiting around for it to rehydrate. This is fine if your with folks and chatting away, but I find nothing worse than being hungry waiting on food while others are already eating. So unless the weather is terrible I think the best method is to make your food up as the first thing you do when you arrive at your camp site, get on with the tent etc and then you should only have to wait another 5-10 minutes before it's done. This should mean you get to eat along with everyone else too.

For the most part things worked perfectly, however the top 20% of the food was not fully rehydrated. This was not really a fault of the method but more the user, I was doing this at home while getting on with other things. I had simply filled the bag then left it, what it needed was a stir up to swap the top and bottom around so everything got a good soaking and could absorb the water. If I were outdoors then this would be something to remember to give things a quick stir halfway through to ensure all the food is even. This was probably also a fault of the bag size. These small bags are really not suited for main meals like this, and even less so using them upright. I'm not sure why but they come with a tear tab at one end so you have a vertical top & bottom as it were. This makes no sense now as you have food that does not mix evenly, small stuff falls down and gets lost. What seems far more logical is to flip it to the horizontal and make a slit along one length. This will give a greater base area and less depth, I think this would also reduce the amount of stirring needed and prevent the issue of trying to scrape out all the stuff from the bottom of the bag with a long spoon.

I have some larger bags on order and will be testing the idea of using them sideways, but generally I think I have it nailed with regards to this particular meal. I haven't a clue on calorie count and I never really check things like that on food at home, so have no basis to compare this on a nutrition level. I did a quick check online and the figures have a dramatic variation but at an average guess I would say there is around 550 calories per portion. But cost wise is as follows.

Mince = £3.00
Sauce = £2.30
Peppers = £1.00
Mushrooms = £0.80
Onions = £0.75
Penne Pasta = £0.30
Extra seasons = £0.50
Total = £8.65

This will generally make enough food for 5 portions giving a portion cost of £1.73 + electric. Considering the average for dried meals is around £5 I have the better part of £3.25 spare change to cover the cost of cooking and drying. Pretty sure even my cooker doesn't guzzle that much electricity and so I think I'm on a winner on the price front. As before I have no basis to compare the taste on this as I generally don't want to get into a pishing contest on which is better on a fork. But I can at least be sure that if I take a bag of this with me and make it up I will have a good meal I know I will like. No doubt plenty of folks have suffered the experience of food you weren't fond of but had no other choice than to force it down.

So now that one is all sorted and put to bed it's time to move onwards and upward. Next challenge to crack the method for doing oaty porridge.