I'm soon to hopefully start building a clay oven and am now considering sizes. I've done a paper cut out of 22.5" and 31.5" diameters, and the first seems too small and the latter too large. It would be nice to cook two pizzas at a time, but probably not a necessity.After the pizza is out I'd like to cook a loaf of bread, and it would be great, should I manage to build a decently insulated oven, to roast a chicken and veg. I'm interested in what those of you that have your own ovens suggest in terms of diameter/size.
A linked question has to then do with the size of the base. Is there a kind of standard calculation I can make, so if the oven diameter = x the base = y?
hello duhva I have no experience with clay ovens as I built a stone oven. mine has the internal diameter of 80cm or 31.5 inches which reading through the forum is the recommended minimum size (for a stone not sure if this applies to clay)and having built it this size would agree.you could easily fit two medium sized pizzas (approx. 10inch) in there though in my early stages of using the oven I find one at a time easier to manage.
im no builder either so not sure of the base but I would imagine that the base needs to only be equal to the oven or greater. im sure someone more experienced to answer your question will be along soon.
good luck with the build please get some pics up if you can.
The smallest sized internal diameter oven (in my view) is 60cm (24").....a good sized domestic oven which works for me is 90cm (36"). Not sure who posted this recently but if you add 20" to internal size of the oven, this will give you enough room for all the correct insulation etc. A Clay oven would only need an extra 10 or 12" to the width as the insulation (pieces of straw or woodchip) is normally integrated into the second thinner layer of clay....5 or 6" in total.
Perhaps you will need a 70cm (28") oven to bake 2 pizzas at a time but in reality as the pizzas only take about 90 seconds to bake, people generally only bake 1 pizza at a time.
n.b...when watching a chap demonstrating the Jamie Oliver 60 dome (60cm) the chap was cooking a chilli (in a square shallow tin) at the rear of the oven while at the same time baking flatbreads (about 9") at the front of the oven.....
Thanks kipper and Terry for sharing your experience and rivergirl, look forward to your reply when you get a sec. Terry, I may come back to you on the insulation piece as some clay ovens I've seen seem to have an extra layer after the clay/straw, and I wonder -- how much insulation is necessary to keep the hear going from pizza to roast to bread (if that's the right order)?
...insulation on the dome of a clay oven....good question!..I've only ever (hey, I'm still learning btw) built clay ovens on a few Clay oven courses and I have used about 3" of clay (1 part clay, 2 parts sand + water) on the first layer and about 2" of the same clay mix with added pieces of straw or woodchips on the second Cob layer. I think this ...or similar is the finished traditional Clay/Cob oven. It has to be waterproof so a shelter is usually constructed to protect the oven.
An extra layer of insulation would improve the heat retention but I'm not sure how much as although I've built quite a few.....I've never baked in one. I once tried to put a waterproof render on top of a clay dome.....when the clay was still wet. I keyed the clay, but the render simply cracked and seperated. If I went down that route again, I would wait until the outer surface was completely dry, then put a 2" layer of sloppy "devils porridge" (vermecrete.....vermiculite, cement and water) on it. The vermecrete can then be covered in a waterproof mortar.
"how much insulation is necessary to keep the heat going from pizza to roast to bread (if that's the right order)?"....
You'd have to get comments from the likes of Rivergirl....or other clay oven users for that, but cooking different things on the same firing is a bit of trial and error. If I had to guess....and I will...I would have my pizza party first, then rake out the embers and let the oven come down in temp.....then bake my batches of bread. I would then start up another small "flickering fire" to cook my roast.
Like I say it's all trial and error but it's good fun getting there. I may be contradicted on my last few comments as many members (probably most of them) are much more experienced than me in cooking in a WFO.
A gentle bump to this thread to see if rivergirl has a chance to post about her clay oven, or anyone else has suggestions -- Terry, thanks for yours. I'm hoping to start work on the base over Easter break.
....it sounds like you are going ahead with your project. Go for it!!. It's a bit of a labour of love....and a lot of hard work, but you will reap the benefits of your hard labour once your project is complete.
If you are thinking of a internal oven diameter of x cm's.......simply build the base 10 inches larger than the width and 20 inches longer in length. You can build a simple wall structure and cast a concrete slab on top of the walls......or simply buy...and lay 4 or 5 re-enforced concrete lintels to go from side to side to be able to lay an insulation block layer......ready to take your hearth bricks.
...Picture attached for this method...
If you're having problems sourcing clay.....shout out....maybe we can help.
Terry, quick question -- just looking at the picture again, are you using a specific type of firebrick? The ones I've been thinking of getting seem to be normal brick size -- 230x116x64 -- where the ones in the photo look more like a paving stone?