What to do with old ovens

Here's my half-brained idea for using an old oven:

Wood burning stove for maple syrup production. It seems too good to be true. if you remove the metal underneath the stove-top elements, theoretically you could cook down sap on all four burners, or block as many off as you want. Does this idea have potential or is it a recipe for disaster? Maybe I should just scrounge some materials for a rocket mass heater to do this instead?

Been there, done that, massive FAIL!  Kinda...

I used a vogelzang BX26E in an outdoor shed with 2 1/2 sides, seasoned but wet unsplit wood, with sap out of a tank at room temp (15 degree room) which was supposed to boil in a tall 5 gallon pot.

I didn't have a chance.

Now I have hindsight to help me out.  What I ended up building was 3 walls out of cinder blocks, 4 courses high.  It fit 2 full size stainless steel steam table inserts running the long way.  A section of durock let me place the smokestack, another piece served as a door at the front.  The fire burned under the front insert, with the smoke and exhaust heating up the rear pan on its way out.  In effect, it was a sort of rocket stove rig, but it did the job up until the ground thawed and the whole thing collapsed.

If I ever move back north and have access to trees, I'd start with a poured slab, use firebrick for lining the interior of the arch, extend the size to hold 3 inserts, rig a better door and flu, and have the whole thing enclosed in a shack with a comfy chair, and vents for the steam.

They made maple syrup way back in the day using a campfire and an iron kettle.  Get creative.

I think I would have to try and make a solar dehydrator! is it the kind that the whole top can be removed?

Ken Peavey wrote:
Been there, done that, massive FAIL!  Kinda...

They made maple syrup way back in the day using a campfire and an iron kettle.  Get creative.

Thanks Ken. I appreciate your hindsight advice.

I tried the campfire method but found it waaaay too inefficient on the wood burning end of things. I'm willing to get creative, hence the oven idea, but I don't want this to blow up in my face (which could happen quite literally)

Leah Sattler wrote:
I think I would have to try and make a solar dehydrator! is it the kind that the whole top can be removed?

Thats an excellent idea Leah, thanks. And yes, the ovens I've found can have their tops removed, or so it appears. They are the generic white ones with a visible outter separation of the top and sides.

I would really like to better understand the sugar shack stoves and how to merge rocket stuff with that, if it isn't merged already.

Another problem I had was the smoke getting into the sap.  The steam coming off the pot is cooler than the smoke.  If not well vented, the smoke will condense on the steam and can settle into the syrup, ruining the batch.

I gave some thought to using a fresnel lens to boil the sap.  I think it can be done, especially when mirrors are used to direct the light to an indoor pot. 

The fire you need going would literally burn up the oven.

You might be able to set up a smoker though, the fire for that is much smaller and cooler. If there is a drawer below, you could build a fire in the drawer(line it with brick first), drill hole in the oven floor, or cut bigger holes, then put the meat to be smoked on the oven racks. You could set racks on top of that to dehydrate stuff.... but of course ONLY use that outdoors

People around here make smokers out of old refridgerators and freezers. There was a fridge in back of the house we had hauled off when we bought our house, later the builder of the house said that was their smoker--now I wish I would have checked it out! He said it worked great. We set our barrel type smoker(the kind you buy in the store, looks like r2d2) on top of a small boxwood stove, that works much better to smoke stuff than making the fire inside the barrel smoker(as it was made to be used).

Yup, properly done an old frig makes a great smoker.

My dad has one he uses it all the time & it works great, he has it in his shop with its own chimney. We love it because we get smoked brisket & sausages & stuff often.

I should imagine you could do the same conversion on an old oven.

I saw an article years ago (Mother Earth News, maybe?) about someone who was using  the idea that solids separate out of water when frozen. So, he was doing at least an initial separation of maple syrup from water by leaving the syrup in buckets to freeze then taking the frozen water off the top. I don't remember if he then boiled the rest of it to further condense the syrup or not.  Has anyone else tried this and does it work?

Pam
I did that last year.  The ice removed is nowhere near as sweet as the sap.  I'm sure some amount of sugar is lost, but the volume of water removed should more than make up for it.  I've not seen data on the % of sugar content in sap with ice removed so I can't back up my claim.  I can tell you the unfrozen sap is considerably darker with ice removed from the top several times.

I bought a stainless steel freezer, an upright  commercial model, a True brand, it had a broken compressor and i got it for $400  , i used a dremel tool with cut off disks to cut the Steel and fitted a damper assembly in each hole the top one is the exhaust and the lower one feeds the smoke in. I like doing both hot and cold smoking so the feed line is attached to the chimney of an old barrel smoker i have. i put a hot plate in it  with a cast iron frypan to hold the sawdust. if i need extra heat for things like bacon , sausages, or hot smoking i add a second 1000 watt hotplate inside the cabinet. it works incredibly well if i were to fill all the shelves i could do 200 lbs of salmon at a time and for sausages or bacon 200lbs at a go would also be possible.  it's well insulated and completely stainless exterior consruction, works like a charm. Bought it at a restaurant auction. Its now in a little roofed  enclosure i built in the yard tight to my garage.