Rocket Stove Maple Syrup Evaporator

Thought about it last year but didn't put much time or effort into it. In theory it should consume much less wood due to the efficient operation of the rocket type stove.

First rocket stove attempt was just some 3" galvanized pipe. It worked and I learned a few things about the principals.









My second attempt was a typical j type rocket used in a mass heater but it would only boil a small pot with the exhaust. I made that out of some fire brick and an old flu liner from a chimney. Not well insulated. The higher temps are in the combustion area and I think this would work if you sunk a pan into the bottom of the j shape of the rocket stove but you would need to fit the pan into that area very precisely to keep the air flow without introducing any leaks.












My third attempt I used some 6" square tube made of 1/4" steel. I used a v shape to move the fuel and therefor the flames closer to the pan. Once I welded it up I fired it and it would boil a pot with a gallon of water but still not what I needed to utilize my 2 sq foot pan that my in laws made me for the top of my small wood stove.





4th attempt I changed the air intake to make this thing really rocket. Once I added the extra air intake it would boil a larger pot with two gallons of water no problem.

Once I did that I used an old two drawer file cabinet to mount it into. I placed a brick on the bottom of the cabinet and placed the rocket on top of it. That brought the top to the perfect height. I sealed it with some sheet metal and filled the whole box with perlite. I capped the perlite on top with some fire brick. That would boil a restaurant pan 3/4 full and shoot flames out the top of the riser and around the pan. Yehaaa!



Just a little more now. I built a shroud around the large pan I have and pushed the exhaust out the back and up some 6" flue pipe.

It will now give me a thriving rolling boil in the 2 sq ft pan with as much fluid as you want. You can see where it was getting too hot on the side of the shroud so I put a fire brick on each side to protect the sheet metal shroud. The shroud is set off the pan about an inch to inch and a half to keep the air flowing.


The best thing is it sips wood. Only the ends of the fuel burns and max is 6" wide so what used to require a full wood stove to operate now just the tips of the wood. It completely consumes every bit of fuel in the combustion chamber so no smoke or soot. Amazing! Still learning but I may try to expand the principals on a larger scale.

Next test burn I will get some pictures of it cranking!


Cant seem to attach pictures

Mike,....looks nice. I haven't done syrup yet, but hope to in the future. What I can't get a feeling for is how much time/effort/cost went into the prototypes. What I'm thinking here is somehow increasing your pan surface area so that the same volume of sap is spread over a larger area, thus getting faster evaporation. Yet an experienced syruper will know if there is diminishing returns from increased surface area: It may become difficult to recover that viscous syrup from a larger pan and not be worth it. In any even, if rocket stoves are being used for this purpose, would it be possible to fabricate three or four stoves in a row out of assembled firebrick?......have them all running at once? With one long rectangular pan placed across all four chimneys, that should evaporate a lot of sap....Maybe?

- O. K. , I'll be the lightening Rod here This is indeed a Successful adaptation of a Rocket Cook Stove, as such it predates the Rocket Mass Heater by nearly 10 years.

It does not have a burn tunnel or a true Heat Riser Though I do expect that it has some insulation. Max temperatures can reach as high as 1000ºF IMHO. It will
definitely burn much hotter and cleaner on less wood that a conventionally fired Maple Syrup arch.

In fact much of the increased performance is from the smaller wood with increased surface area ! The one major thing they have in common is very true of most kinds
of Solid Fuel heaters and that is a major difficulty of throttling ether stove back, except by the practice of not 'feeding them any more fuel'

It will be interesting to see the tweaks necessary to achieve the longevity of these new modifications !

I just want to make sure that a clear line is drawn between the characteristics of this Rocket (Cook) Stove and the Rocket Mass Heater

I product that the next big change will actually be a series of very modest steps as we adapt the Rocket (cook) Stove to work with a near conventional evaporator pan,
and the evaporator pan with this (cook) Stove and perhaps a modification of the basic arch !

For the Good of All the Crafts ! Big AL

The surface area is the determining factor for evaporation. You can expect 1 gallon of evaporation per hour with one square foot of surface area. A pan with flues in it will double that evaporation rate. I am using a flat pan. I also run a 10 sq foot pan on a more traditional arch.

I think I can add some more pictures with this post of the prototypes.

I would also like to use the flow from the flue to warm my butt down the road.

Using two plates that cover the inputs I can control the fire pretty well or even shut the stove right down by starving it.

Your idea of perhaps 4 rockets in a row may be in the future. Spreading the flow of heat exiting the riser will also be something to work on from the prototype when 2015 syrup season is over.

Just a couple when it is running