The Fresh Loaf

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DIY Portable Backyard Bread Oven Project

HeiHei29er's picture
HeiHei29er

DIY Portable Backyard Bread Oven Project

Last year, we used a Dutch oven to make a loaf of sourdough over a campfire.  It kind of worked, but it was less than ideal.  I wanted to make something that I could take camping with us, but also something that could be used at the house to bake a loaf outside in the summer instead of heating up the house.  After about 3-4 months of planning and scheming, the prototype is getting close to a reality.  Hoping to do the first bake with it in a couple weeks.

 

Rempejek's picture
Rempejek

Interesting as I am working on something as well, but with fire bricks

Keep us all posted please

HeiHei29er's picture
HeiHei29er

Will do.  I almost pulled the trigger on a red clay brick design too.  Just couldn’t come up with a way to make it easily portable.

idaveindy's picture
idaveindy

Cool project!   As Tim the tool man would say: Argh! Argh! Argh!

Things may have changed, or you may be aware of exceptions that I'm not aware of... 

that said, ...  I once researched DIY baking stones, even contacting a flooring tile manufacturer who said " no" to food use of ceramic floor tiles because they out-gas, glazed or not.

Natural stone or clean clay is needed:  

- granite or marble - no epoxy "fills".   I have a 1' x 2' pure granite floor tile, no fillers, and polished on one side that I plan to cut to size.

- Unglazed "quarry tiles" are also mentioned as safe, but now being manufactured mostly outside the US, you can't trust there are no toxic fillers or inclusions.  

- Travertine tiles are mentioned as safe, but all have some degree of clay fillers. And you don't know what is in the clay.

So granite or marble, well-inspected, seems the safest baking surface.

Good luck, amigo/

HeiHei29er's picture
HeiHei29er

Thanks for the heads up!  

I'll do a little digging on that.  I could possibly get a custom sized Fibrament stone too, but I don't know how thin they make them.  My Fibrament oven stone is close to 1" thick and that would take up too much vertical height.  I'm somewhat height challenged on this project.  My barrel was probably a tad too small and there were too many unknowns before firing it.  After last night, I think I could have gone a bit taller.

I understand the concern with off-gassing in the ceramic, but I'm curious on what's left to off gas after it's been heated 2-3 times over 500 deg.  That was one of the other reasons for heating it up last night...  Burn off anything that wasn't capable of handling those temps.  Need to do a little more digging.  I think I can get a marble floor tile at Menards or Home Depot if I have to go that route.

  

idaveindy's picture
idaveindy

I'm not a materials engineer or scientist so I can't say for certain, but "ceramics" may  have things in them that specific purpose refractory materials don't.

Refractory or "fire brick" is designed/intended to be heated thousands of times, thousands of hours.  Floor tile "ceramics" are designed to be fired a couple three times at the factory and expected/intended to never be fired again.  

Think red bricks for chimney versus red bricks for exterior wall decoration. Should a home builder know the difference, or is "brick is brick is brick" ?

I don't think it's logical to assume "all the possible 'bad stuff' has been burned off."   Heat does things to chemicals, and not necessarily all at once or all up front. It may be a "slowly, over time" thing, and it may be a chain wherein it isn't until  the 2nd, 3rd or more, order heat-induced by-product that it turns toxic. A quickly turns to B, B is what they want in the tile, but further firing might make B slowly turn to C, and then C breaks down to something toxic.  Just imagining possibilities.  

So yeah, check with tile manufacturers.

I forget exact measurements, but I seem to recall that tavertine and granite can come in 1/4" thickness.

HeiHei29er's picture
HeiHei29er

I think it's unlikely that additional reactions are occurring.  The material is fairly porous and anything volatile in any binders would have volatilized and off-gassed in the kiln step during manufacturing.  They take it to much higher temps than what I'm hitting in the oven.

However, your point about heat cycles is a good one and that's probably where any risk lies.  If the material contains any heavy metals or fibers, they may become airborne and get inhaled/ingested as dust if the tile breaks down.  I can definitely see how that could happen.

I'll take a look at a Lowes or Home Depot this week and see if I can find a granite or marble tile.

Mini Oven's picture
Mini Oven

oven in Indonesia 30 some years ago.  It was a light weight DIY from a local sold in the market. It was a recycle large square shaped cooking oil can with a hole cut in one side to sit over the heat source (gas stove) a baking chamber floor and glass door built into it. Venting holes high at the back and around the inside of the baking chamber and one little rack shelf.  I put an oven thermometer in it and set it on 4 tuna cans to hold it up.  Had a handle on top to lift it when hot or to hang onto it when the door was opened. (Which threw it off balance when empty.)  It could easily be set over campfire coals and such.  This might be something to think about.

 I would still use your bucket oven but adapt it to make something similar...(option: cut a bigger hole in the bottom, more the size of a small pizza and add some long legs so it could sit over a small camp fire, grill starter, or camping stove.) No need for an upper chimney to create maybe too much draft.  A couple of side/ top handles and maybe a turn vent (like on most grills) on top to control the draft in the outside heating chamber.  No need for tiles, just a shelf that holds the dough off the bottom to prevent burning. It doesn't take much heat to heat up the oven and bake a loaf of bread.  

Rempejek's picture
Rempejek

I like that Mini!

Do you have any pictures by any chance?

HeiHei29er's picture
HeiHei29er

Thanks for the ideas Mini! Some of these are right in-line with phase 2.  Phase 1 was proof of concept and making sure it would even get to baking temps.  Phase 2 is making it functional.  :-)

You're spot on about airflow and I have a damper for the stack on the top to let me control it.  Handles are a good idea to help make it portable when not in use.  I think I can put them into each side before I insulate and wrap it.  Still need to work out a vent for the bread chamber.  Plan to just crack the door for now but some kind of grill type vent would probably work quite well. I don't think it would need to be very big.  I like the idea of a rack versus a stone!  I always use parchment paper anyway.  Need to see if I can come up with something that doesn't take too much height.

I'll likely stick with the rocket stove concept.  It looks more complicated than it is.  The combustion chamber and tall stack are actually one piece and the oven compartment is another.  The tall stand it sits on a third piece.  So I can disassemble it and reassemble it somewhere else in a matter of minutes. From assembly to baking bread in maybe 20 minutes.  I like the fact that it's self contained, can be set up anywhere with ease, and is extremely fuel efficient (I can bake bread with the sticks I pick up in my yard each spring). 

MTloaf's picture
MTloaf

A sheepherders stove that they put in wall tents out west.
Like these https://www.walltentshop.com/products/cylinder-stoves 

Sounds like a fun project. 
Don

HeiHei29er's picture
HeiHei29er

That little oven in the chimney pipe is exactly what I have!

I love to tinker, so yeah, this has been a fun project.  Will be even better if it works.  😁

foodforthought's picture
foodforthought

Our ovens had stubby legs and a raised rim on the lid. The trick was to place coals on the lid as well as under the oven. We even developed specific protocols for the number of briquettes above and below for different recipes: biscuits as opposed to brownies, etc. We got pretty good at not burning things plus what doesn’t taste great when your camping under the stars…

Good luck on the project, though you might want to give the Dutch oven another shot. YouTube video is totally Rube Goldberg, but looks like a fun diversion.

Phil

HeiHei29er's picture
HeiHei29er

I’ll apologize upfront for the awkward video at times.  I wasn’t quite coordinated enough to video with one hand and bake with the other.  Need to find a video crew (or at least a tripod) for the next update. 😁

Updates…

- insulated and cladded 

- polished marble instead of ceramic tile

- damper added to vent stack

Thought it worked really well for the initial bake.  Got a little hot and burned the bottom of the first loaf.  Used a little rack in the second loaf and it turned out much better.  Since then, I thought a bit more about my electric oven setup and have added a distributor plate under the baking chamber to avoid the heat impinging directly below the stones.  Hoping that prevents the hot spot in the center of the chamber.

(for crumb shots at the end, 1st loaf is on the right and 2nd loaf is on the left)

Next bake with it will be this weekend!

MTloaf's picture
MTloaf

Congrats on the baptismal fire. The oven shows promise and with just a few tweaks will do a fine job. Did the switch to marble from clay make a difference? I am thinking that starting the bake on the stone and then putting the loaf on a taller rack would work better. If you have any money left over after buying that loading peel;-) I would also recommend getting an IR thermometer to see just how hot the stone is. It is a vital tool with my pizza oven. 

Don

HeiHei29er's picture
HeiHei29er

Thanks Don!  I was encouraged after the first couple loaves, and being a stubborn engineer, I WILL keep tinkering until I get it right.  :-)   Never used the ceramic tile based on concerns that idaveindy mentioned above so no comparison....

The small cooling rack is one I had at the house.  If I stay with that route, I'll want something larger that's easier to get the bread on without worrying about it falling off during the transition.  Before buying a new rack, I made something with a piece of sheet steel that acts as a deflector below the oven chamber.  Should eliminate the heat going directly from the stack to the bottom of the oven.  That's step one.  It was cheap and if it works will eliminate the double dough handling.  Step 2 will be buying a larger rack. 

I like the idea of the IR gun.  Laying the thermocouple on the stones works pretty well, but I know it's measuring both the stone temp and the oven temp.  Not ideal...

As far as the peel...  One of the advantages of living in an area where bird's eye can be found.  Sometimes you know a guy with a board...  :-)   That was a DIY too. 

MTloaf's picture
MTloaf

At first glance on my small screen I  mistook the bird’s eye maple for a piece of wafer board plywood so never mind my comment. However I would look for something better to use as a spacer for the stone besides a piece of sheet rock. It am afraid it will burn and off gas

With the stone being so hot it might do a nice job with pizza. 

HeiHei29er's picture
HeiHei29er

LoL!  All good.  

I should have said flat stock instead of sheet stock.  Agree that sheet rock would be a bad choice.

idaveindy's picture
idaveindy

Just saw the video. That does look cool!   You're good with tools.

In addition to a flame/heat baffle under the baking chamber, putting the marble stone on 3 or 4 small legs, even just 2 to 3 mm tall, will reduce the conduction heating between the metal oven floor and the stone, and likely allow its temp to be more uniform, and closer to the oven's air temp.  

The stone will still heat up via both radiation and convection heating. (IE, the metal floor of the oven will still radiate much heat across the 3mm gap.

I second MT's suggestion of a laser thermometer to read the stone temp.

HeiHei29er's picture
HeiHei29er

Thanks Dave.  I'm always open to ideers!  :-)

I like that one too!  Would be easy to lay a couple strips of sheet stock along each edge and use that as the lift for the stones.

Mini Oven's picture
Mini Oven

you slip the rack under the stone before heating it?  

The stone might be cooler for loaves with more even heat distribution. 

Great test run!

HeiHei29er's picture
HeiHei29er

That could work too, but I’d need a bigger rack.  The one I have now is pretty small, and the marble is actually two tiles cut to fit.  Would need a rack big enough to support both of them.

 

Mini Oven's picture
Mini Oven

How about a few large bolts scattered about the oven floor?

HeiHei29er's picture
HeiHei29er

That would work too.  Here’s what I went with for this round.  Enough space to create an air gap but have minimal impact on oven height.  If that’s not enough, I’ll get it up a little higher.

HeiHei29er's picture
HeiHei29er

This has been one of those summer-long projects that I get myself into.  It's the end of summer, so happy to report that it's getting close!  Video link below...  Unfortunately, the pan loaf was overproofed.  There is a massive bubble underneath the top crust now that things have cooled.  It's a 30% semolina bread made with ADY.  I let it bench rest for 30 minutes after shaping and before cold retarding.  In hind sight, it should have gone straight into the refrigerator.  Lesson learned!  Happy with how the oven performed though.  :-)  

 

HeiHei29er's picture
HeiHei29er

Now that’s a cavern!  🤣