Dehydrating meals with a fan oven?

16 messages
24/03/2012 at 22:35
I was considering trying to make my own backpacking meals but dehydrators seem very expensive for the amount of use I'd get out of one. Does anyone have any experience with using a fan oven instead? I've successfully used mine on its lowest setting (about 60C) to dry things like chillis before but I'm unsure whether it would work for a complete meal.
24/03/2012 at 22:40

I dunno about using the oven, but someone on here (Dids/Mole?) recently linked to a dehydrator that was only about £20.

I can't find the thread in the search btw. 

Include a little history in your walks. Pecsaetan - Ancient Derbyshire, Staffordshire and South Yorkshire -

24/03/2012 at 22:42

Ah, here we are.

Courtesy of Google.

(Why is the search facility here so crap?)

Include a little history in your walks. Pecsaetan - Ancient Derbyshire, Staffordshire and South Yorkshire -

24/03/2012 at 22:47

Thanks - that's not so bad then, but it doesn't have a fan which my brief internet research suggests is important or at least recommended. The cheapest I'd found with a fan was about £45 and it wasn't getting very good reviews.

If the fan oven would work then it'd be a bonus as it has all the features of an expensive dehydrator:
 - A fan (!)
 - A thermostat
 - A timer
 - A large capacity

Maybe I should just give it a go. I'm not overly bothered about wasting one portion of food on a trial run if it doesn't work, I'm more concerned about potentially making myself ill if it fails to completely dehydrate and/or takes so long that bacteria builds up.

Edited: 24/03/2012 at 22:50
24/03/2012 at 23:19

Hmm, those are some intersting points. It's a reasonably good oven so has upper and lower elements so I was hoping that plus the fan would keep temperatures even, but yes if the temperature fluctuates significantly that would just mean it does so evenly! You're right about water vapour, I found when drying chillis that it worked a lot better if I cracked the door for a few seconds now and again.

24/03/2012 at 23:38
I have used a gas oven (with the door a bit open)  to dry meat and the occasional full meal (IE curry leftovers, pasta and meat sauce) but I do fruit and veggies in a dehydrator with fan and thermostat.No, I would not consider one without those two features..Meat : it is important to use as fat free as possible meat (except for curries if used relatively quickly, the spices will keep it safe . nutmeg is the golden spice for that..)Never buy mince meat. Make your own. (cut out the fatty bits)Pork can be very lean .Franco
25/03/2012 at 00:34
I've used the oven to dry fruit leather. That was before I got a dehydrator. The oven was OK, but took for ever and meanwhile you cannot use it to cook. Obviously a fan oven is best but not essential. You must leave the door propped open a wee bit or the moisture will not escape.
Any temperature variation is likely to affect the quality of the taste/texture of the food but I would not think it would affect the keeping qualities. Once the food is dehydrated/dry then it is 'dry' and it is the lack of moisture which effectively preserves it.

Can you get a second hand dehydrator? Mine was 2nd hand. I use it for other things too - rising bread, drying out down/feathers (-don't ask!!) etc.
I've seen plans on the net for creating a dehydrator using a kitchen cupboard and a light bulb! ??

Good luck.
Edited: 25/03/2012 at 00:34
25/03/2012 at 19:05
mince meat is possible if it's pure beef. Oké it's still fat but if you use it within 2-3 months it's oké.

26/03/2012 at 22:39
Nobody thought of just leaving the door open a little? Would totally screw up temperature regulation but would solve letting water vapour escape.
26/03/2012 at 22:40
Haha, in regards to my last post I should learn not to just read the first couple of posts then skip to the bottom!
26/03/2012 at 22:43

Nobody thought of just leaving the door open a little?After both myself and Cathy mentioned that, everybody else probably thought that it had been mentioned enough...

and I should learn to type faster...

Edited: 26/03/2012 at 22:44
27/03/2012 at 00:43

The other factor you might want to consider is the cost of running an oven for (probably) several hours compared to the small electric motor and heating element in a dehydrator.

An oven is a pretty big space to heat and if you're only occupying, say, 5% of the volume with food, that's a lot of wasted heat, especially with the door open.  A dehydrator has very little unused space by comparison.

A couple of years ago, I did work out the cost of running my dehydrator and it was literally pennies.  I would be very surprised if an oven was anything like as cheap.  

31/03/2012 at 00:28
didy and ray use a £25 dehydrater - it works well but i am a cook eat and no faff person.  pm them for 1h meals
31/03/2012 at 00:38
My, what a splendid username you have there.

Include a little history in your walks. Pecsaetan - Ancient Derbyshire, Staffordshire and South Yorkshire -

31/03/2012 at 01:00
The Laser 2000 from Westfalia is a good buy for £33, no timer on them but I just use one of those plug in socket timer jobbies. Either that or stick it on at night and check in the morning.

I haven;t bought any more £5 meals from the shops since last September so it's been well worth the investment. I use the Pour&Store bags from Morrisons which take boiling water and slot nicely into a cosy.
08/04/2012 at 18:16

Ok, so I actually got around to trying this. I was making a big load of bolognese so decided to test it with a small sample.

Before (ignore the slightly neon orange colour, the camera got the white balance wrong!):



To get to that result I ran my fan oven for 4 hours with the temperature set to 60C and the door wedged open slightly using an oven glove. About halfway through I moved everything around and dabbed off some drops of fat I could see. By the end of the four hour process it was dry to the point of being crumbly so I sealed it in a freezer bag and left it overnight.

By the morning it had softened a bit so I'm thinking that could either be because of fat still seeping out or just what happens as it cools down. I rehydrated it today and, while it's not going to win any Michelin stars, it was ok and I haven't suffered any ill effects!

A few notes:

  • Without really thinking about what I was doing, I included some bacon in the recipe because I usually do. I'm guessing that this is probably why it seemed quite fatty when dehydrating despite me having drained the fat from the mince after browning it. Lesson learned: no bacon for dehydrating!
  • I also included celery and carrot as usual. These definitely took their time to dry, so if I was making it specifically for dehydration I would stick them in the food processor to make them as small as possible.
  • Similarly, I used chopped tomatoes. Again this resulted in some large chunks taking a while to dry out. Next time I'll use sieved tomatoes.

Finally, I was a bit concerned this would be ridiculously expensive in terms of electricity usage so I read the meter before and afterwards. Result: 2 kWh was used or (as I'm on an economy 7 tariff) about 50p, but if I was to run it overnight using the oven timer then that changes to 9p. I would have no safety concerns doing so as the temperature in the oven never got anywhere near levels which could cause a problem, I was lifting the metal rack in and out with my bare hands with no issue.

Overall, a better result than I expected I think.

Edited: 08/04/2012 at 18:20
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