Introduction: Simple (Deluxe!) Sonotube Food Dehydrator

I have always wanted to make a REAL food dehydrator, but all the plans I have found always start out "make a box..." That lets me out! I don't have the patience to make a box, let alone the skills to make it square, then add racks (also square!!) so I came up with a super easy way to make a container that looks like the commercial dehydrators using stacking trays in a cylindrical shape. It took me less than an hour and cost about 20 dollars. I could have scavenged and cut that in half, as I am sure many of you readers can. Read on!

Step 1: Things You Will Need

This design is so easy to make, all you need is a cylindrical tube, sold as a concrete form at the hardware store for around 5 dollars. They come in different diameters, I chose 30 cm. You will need some mosquito net, a zip knife to make the racks, and a staple gun to fix the net to the tube sections. For the drying unit I used an old heater made for warming up the car interior. Don't really know what you would call that in the US, since I grew up in Texas, and the last thing we would ever invent is a way to warm up the car interior! But here in Sweden it is common to own 2 of the things... Mine has variable heat settings, from 500 W to 2000 W and is built for 100% duty cycle, or constant running without overheating. (I paid 5 dollars at a local auction) I fould a small electric space heater online for about 15 dollars that would work. Add an oven thermometer and we're in business.

Step 2: Handy Tip

Use a zip knife, or box cutting knife to cut the tube into sections. Before cutting, draw a line lenghtwise along the entire tube. This will make it easy to stack the baskets so they fit perfectly and won't leak warm air. I also marked each basket with THIS SIDE UP and numbered them to ease in assembly. The base section is about six inches (15 cm) tall, and each stacking section is 2 inches (5 cm).

Step 3: How to Use a Zip Knife

When cutting cardboard (thick or thin) with a zip knife or an exacto knife, it will cut like butter if you tilt the blade in relation to the object being cut. In other words, don't stick the blade straight in and push, tilt the entire knife and saw in short strokes. In thin cardboard you can cut fantastic curves and shapes like this, but the tube I used is about 3/8 inches thick, so it was a more difficult job. Still, I cut 5 slices off the tube in about 15 minutes. Draw a guideline around the tube to follow when you cut. (You don't really need detailed instructions for that, do you?) The baskets don't need to be exactly straight, since the knife doesn't make any kerf, they will stack without any gaps between them.

Step 4: Attatching Netting

Cut out mosquito netting to fit the baskets. Cut the net slightly larger than the baskets, so we can staple it onto the tube. Stretch the netting slightly and staple it all the way around the tube.

Step 5: In With the Good Air, Out With the Bad!

I added a top to my dehydrator that included a flange to attatch the ventilation hose off my electric clothes drier in the basement. That lets me send the air from the dehydrator out through the vent in the wall. You can do this or just leave a hole in the top for the air to circulate. Your room will be MUCH warmer that way, but it smells good!

Step 6: One Last Step

I made an opening in the base for the heater, (shown in this step) being careful not to cover the fan intake. And That's IT!

Step 7: Thar She Blows!

I filled up the baskets with pears sliced on my old fashioned apple corer-peeler-slicer http://www.applesource.com/peeler.html (love that thing) and gave her a go. My oven thermometer showed 50 C after about 5 minutes. I wanted a little bit warmer, so I plugged the space under the heater with some dense foam rubber and the temp rose to 65 C in no time at all, that's about 150 F. Three hours later I had dried fruit!

I still have half of the tube left! I think I can cut some holes in the side of the tube, insert wooden sticks through the holes and use it for drying jerky. Hang the meat on the sticks and let 'er rip. Maybe a drip pan or something to keep the heater clean? Enjoy!

Comments

author
iamaqtpoo (author)2013-01-05

Thanks os much for your time & effort on this instructable!

author
snub160 (author)2012-06-24

Real "kick-ass" dryer, think I'll try it . You could use two large tubes the outside one to cover the shelves, keep more heat in and make it look a bit prettier? anyway really great, nice and easy too which make all the difference!

author
Paulakise (author)2011-07-28

When you dry meat like that it's called biltong South African tradition.
Don't rli know y im telin yall this cos im vegetarien! anyways planing 2 make my own dehydrator soon for fruit. Probably will use the box and lightbulb method! :-) anyways nice tutorial dude

author
TAnderson7 (author)2011-04-15

Wow that is an amazing project. I really want to try this one! Hopefully I can find the parts this weekend, I am ready to start drying some food!
food dehydrator reviews

author
Mindmapper1 (author)2011-01-02

This is an interesting idea but I fear not really practical or safe for many of reasons given above by others. Drying too quickly is as bad as drying to slowly. The cardboard tube WILL absorb and be a breading ground for bugs which could kill the young, elderly or vulnerable.
My biggest concern about this design is the high risk of fire. Unless this is supervised and never left un attended then there is a significant risk here. I am currently building and writing my instructions for what I believe will be a safe and efficient dehydrator.

author

Constructive thoughts, and I thank you for sharing them. Drying too quickly? I have never come across any warnings about that. As far as any ill effects, I have used it for a number of years to dry mushrooms without any signs of detrimental effects at all. Use this at your own risk, but I say all fears are unconfirmed in practice. Danger of fire cannot be denied. I use a thermometer and keep the device under constant watch. I never allow the temperature to exceed 60 deg C. The cardboard shows no signs of becoming damp, nor are there any signs of moulds or other damages.

Again, thanks for your comments. I look forward to seeing your design with improvements.

author
astro boy (author)2008-09-12

could you make home made popcorn
corn + dehidration = popcorn seed + heat = home made popcorn?

author

Great equation there... :P

author
AidanG (author)astro boy2008-09-12

Popcorn's a specific variety of corn. Also, it has to dry on the cob first, or else you destory the shell which makes the popping possible. So, no. :( But lots of things you CAN make - jerky, fruit leather, apple bits for your oatmeal, instant soup... Seriously! Dry some broth / soup (with very small bits of veggies or meat, if any, and no pasta) in shallow bowls, plates, what have you. When it's very dry, crumble it up, put in a jar, and refrigerate. There are still fats in there which could go rancid. Just add water later... I use beef broth, beef jerky, dried tomatoes, potatoes, parsley, and pasta (from the store). Pretty good stuff!

author
Freakin Einstein (author)AidanG2008-09-20

Or you could just leave it in the can...

author
AidanG (author)Freakin Einstein2008-09-20

Have you carried 5 days worth of canned soup into the woods for backpacking? HEAVY! :) Dehydrated soup is LOTS lighter.

author
Freakin Einstein (author)AidanG2008-09-21

Yes I can imagine...I try to stay out of the woods...That's where the bears are. =:]

author

Bears...rrrrrriiiiiigghhtttt

author
Splortched (author)RedneckAsian2009-01-04

Da Beeeeeaaaaaaaars...

author
robot797 (author)Splortched2009-05-25

aaaw cute bear aaaaa bear dont eat me aaa......(dead)

author
JellyWoo (author)2008-09-09

what exactly does this do? sry for the stupid question

author
mynameisjonas (author)JellyWoo2009-01-05

it takes the moisture out of food so it lasts longer and doesn't need to be refrigerated. some examples are beef jerky, raisins, ect.

author
ClayOgre (author)2008-12-25

I kind of wonder about what kind of glue they used to make that sonitube and if it has any tendency to outgas when subjected to the heat of the dehydrating process and if there is outgassing...what effect there is on the food.

author
wingman358 (author)2008-11-06

Great instructable! I've been trying to find a way to build a dehydrator and this is perfect for my needs - clear, concise, and well-executed. Good job and thanks for the tips :]

author
rmullins (author)2008-10-05

this is one of the most cleverly simple things I have ever seen built on Instructables! Great job! I'm going right out tomorrow and getting a concrete form tube!

author
Freakin Einstein (author)2008-09-20

Nice....Think I'll give it a try. I especially like the dryer hose. Found any stray socks yet..?

author
shilohjim (author)2008-09-10

How do you keep the rings stacked? In other words, how do you keep them from slipping off one another? I recommend the book "Dry it You'll Like it" it has lots of great drying tips. I'm making a dehydrater myself. I'm using a large cardboard box from U-Haul called a wardrobe box so the box part was ready made. I'm using 4 100 watt lamps for my heat generator. Great idea using the tube.

author
maven (author)shilohjim2008-09-12

Since the tubes were cut at an angle, I imagine they would fit tightly back together like a lid on a box...

author
stringstretcher (author)2008-09-12

Lots of interesting comments... Forget about sundrying, it is not possible in autumn in Scandinavia, hence my attempt at an alternative solution. Perhaps in the warmer climates... As to being afraid of cooties: ancient man has dried foods and the race survived until we have become the uber-humans we are today ;-) I personally dropped my chewing gum and put it right back in my mouth a thousand times, despite repeated warnings of a sure death from my mother. (Drank from the water hose, too!) Jokes aside, read all available info on other sites and form your own opinions about risks and do as you please. I am not an expert here, but I am comfortable with this setup according to my needs and so far have not experienced one negative event in this endeavour. Maybe long term effects will turn up, but then, we are all exposed to dangers in our houses and cars... so much more so than this thing does. I have eaten a gob of foods dried in my box and feel great :-) One more comment about moisture: The purpose of the hose on top is to allow moisture to escape, which I can assure you it does. There is not enough heat to "cook" the foods, experts and cookbooks reccomend 50-60 deg C, which I monitor with my thermometer... at that temp full drying after 3 hours is accomplished. I tried with a light bulb and a box fan, took over 12 hours. Sceptics need not attempt this.

author
fizil (author)2008-09-10

Pretty cool! I am still wary making my own settup mainly because of the concerns of what is food safe. In this case i'd be worried about the lube inside the sonotube tube as well as how to clean residue left on the netting.

author
stringstretcher (author)fizil2008-09-10

No lube in the tube! Nothing even touches the tube... residue? Heck, cornflakes come in a cardboard box ;-) Do you mean food that sticks to the netting? With the fruits I have done there have been no particles at all, and I have not seen any warnings on any other sites. Perhaps with meat there would be a problem.

author

fruits will dry with little residue just bleach the tray before you put the next bunch on ...Meat will drip some more then others ..I used a old ice chest with trays set in it on wooden runners stapled to the chest ....family members got me 2 store bought round ones ....with meat clean the trays and then bleach them clean once more then bleach 1 more time ...get any drips cleaned and you should be OK ...in the 18 years or so I have been making jerky no one has gotten sick .......use lemon juice on apples and other fruits to avoid color change ...meat use your fav whatever to taste ....well made tho I worry about heat and cardboard and any grease that may drip on it

author

"Bleach" the tray? Should I scrub the tray with a bleach solution or...? My setup seems to be a lot more temporary than a commercial drier... Perhaps a liner that can be taken out and cleaned after each use? As to heat, I ran the temp up to 80C under supervision, then lowered it to 40 for the rest of the drying process for the jerky. 40C is about body temp, so there is not enough heat to catch anything on fire there. Just do not cover the heater up. I made another variation for drying meat: I drilled holes in the sides of the trays and inserted bamboo skewers through the holes to make a kind of rack. The meat rested on this rack, with a drip pan underneath (which did not collect one single drip). After drying I removed the skewers and replaced them with clean ones. They are cheap and biodegradable ;-) and prevent a cleanup hassle. Am I being nonchalant here? Don't want to take a shortcut that will get me in trouble. Thanks for all the help!

author

I used avry wire for the home made one and 2 low wattage light bulbs on dimmer switches on both sides of the ice chest...the wire made it easy to bleach but I did use wood to hold the wire so it needed to be replaces ...the one that was bought for me is plastic so it can be bleached ...I get no fat dripping if I trim the meat right or use deer or other game animals ...c turkey has dripped even with breast meat ....I hadent thought of skewers would make moving the meat easy .....enjoy

author
Ouroboros439 (author)2008-09-11

You need to get a food grade shellac to coat the inside of the card board to stop it from soaking up any moisture given off from any of these processes. Moisture and cardboard equal a nasty little problem called mold.

author
frankdirt (author)2008-09-11

When I was a kid my dad decided to dry a bunch of onions. BAD IDEA! Our house and all our laundry reeked of onions following that. Luckily, he discovered a recipe for raspberry fruit leather, and he redeemed himself.

author
Meatwolf (author)2008-09-11

With this setup you're not so much drying the food as cooking it. Try taking out the heater and using a box fan? Then you'll actually be drying. By the way, dryers for fruit don't equal dryers for meats. You have to do meat differently to ensure it's safe to eat.

author
hygicell (author)2008-09-11

replace the white exit tube by a length of blackened pipe eliminate the heater put the lot on spacers to allow fresh air entering below put the whole system behind a south facing window or outside on a fine day let the sun do your drying

author
djsc (author)hygicell2008-09-11

I'm with you. missed the opportunity for this year but at least i'll be ready next summer.

author
i.am.flink (author)2008-09-11

If you have enough air flow, you don't even need heat. I tried Alton Brown's (Good Eats) method. Works like a champ.

author
Stylo (author)2008-09-11

You forgot to mention the part where you disassembled the heater and meticulously cleaned and disinfected the intake, fan and element...because you did that right? IMHO, looks like there would be many, many years or organic residue (hair, pet dander, mould, insects etc...) on the internals of this heater, gently permeating and drying into your food. Unless that's the flavor your going for A diluted bleach solution should do fine. There are many commercially available food grade cleaners on the market as well.

author
RetroTechno (author)2008-09-10

Isn't it a little dangerous to be using a space heater near all of that combustible cardboard? Space heaters have caused many a house to burn down.

author

Probably a good idea to keep an idea on things, but I am only running mine at 50 deg C... Still, you are wise to point that out.

author
stringstretcher (author)2008-09-10

Well... pears and apples don't tend to jump around that much while being dried ;-) so I just kinda stacked the rings and they stayed that way. If it ain't broke, don't fix it! Thanks for the book tip, good luck with yours! I am drying jerky today, followed instructions at DIYjerky.com

author
stringstretcher (author)2008-09-09

Thanks for the link to Alton's tips... good ideas there to try. As for what this does, it lets me conserve some of the fruit from our yard so that I can eat them in stead of watching go bad before being able to use them! I can only freeze so much, and drying pears and apples is a great alternative to canning.

author
slyty (author)2008-09-09

Alton Brown has good DIY ideas in his food drying episodes of Good Eats, here's a transcript

author
mettaurlover (author)2008-09-09

it is called an air conditioner, even if it heats it: air conditioning is conditioning the air, even if it means heating it.

author
stringstretcher (author)2008-09-09

That is pretty much what I did. This was way too easy, compared to making a box and shelves and all that!

author
dacker (author)2008-09-09

An easy way to draw the cut line around the circumference of the tube is to find a block of wood or similar inanimate object that is the same height as the height of your cut. Hold a pencil on top of the block of wood and either rotate the tube and hold the block/pencil stationary or vice-versa. Come to think of it, your old compass from that geometry class you hated in high school would work as well.

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