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Post by Fat Bob on Apr 15, 2012 23:27:40 GMT
I do not want to cook pig overnight but I do want to cook pizza in a high temperature oven on a minimum of fuel, in a few minutes and have the benefit of cooking with wood and the flavour it imparts.
We cook bread in a different ZTM oven daily, a loaf takes just a few kindling sticks to bake.
It is not necessary to use lots of wood to cook pizza or bread.
Thermal mass is great if it came free but you only get what you put in - it may do the job but it is not very efficient for small batches.
I am sure we could up efficiency by a small percent in a ZTM WFO but I wonder whether it would be worth the effort.
Just to be absolutely clear our ZTM pizza and bread oven are nothing like the oven shown at the beginning of this thread.
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Post by tonyb on Apr 16, 2012 8:11:49 GMT
I don't see the issue of thermal mass as good or bad, (I take a similar view regarding insulation). There are pros and cons to thermal mass which I've posted at length on the forum.
The key issue is about what people want to cook in their wfo, if its just pizza, maybe a little grilling, short term roasting and the occasional loaf, then I think a low thermal mass oven is probably a good choice. If you want to add multi hour roasting, multiple batches of bread, lower temp cooking etc then you need lots of thermal mass.
Wrt the specific points you make:
- I'm a little sceptical of your 'few kindling sticks' comment.
- I agree about the 'cost' of thermal mass.
- I agree that a few percent efficiency in a domestic situation is probably not an issue
Any chance you could post a picture and spec of your wfo?
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Post by Terry Hardwood on Apr 16, 2012 8:44:25 GMT
- I'm a little sceptical of your 'few kindling sticks' comment. I had the same thought, Tony.
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Post by turkey on Apr 16, 2012 9:27:33 GMT
I am very interested in the ZTM idea. A few sticks may sound far fetched but when i think about it a few things come to mind. To cook the pizza we need a high heat. A pizza should cook ideally in 90 seconds aparently. now given metal is a great conductor and will absorb and release heat very quickly it stands to some reason that a dome (assuming traditional design) of sufficient gague metal would hold enough heat. I suspect the design issue might be how to get the pizza inand done quick enough, but a small fire in there would keep heat up. I am sure we saw a bell oven or something similar posted on the old forum the guy was baking bread in. I am sure a pizza would also cook in this news.bbc.co.uk/local/oxford/hi/people_and_places/newsid_9316000/9316640.stmThanks to happy baker for finding it. I would love to see some pics of this experiment and a video would be even better, but I realise that might not be possible.
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Post by tonyb on Apr 16, 2012 10:18:18 GMT
Turkey, I think the reference to a few pieces of kindling was in relation to baking bread not pizza, ie much lower temps. You also need to remember that its not just about the dome of a wfo but also the floor, which is equally important in cooking a pizza.
I come back to my key point which is you can make a pizza oven, out of just about anything provided you can heat it to 400C+ and this has very little to do with thermal mass or insulation but the actual design and materials will limit the range of food and style of cooking. Before building a wfo people need to be clear about how they are going to use their wfo and pick a design and materials to suit.
To reiterate something we are regularly pointing out on the forum: there are many and varied possible wfo designs, all of which will do a job and as a forum we will try and support anyone looking for help irrespective of the design they favour. Its not just about pompeii or barrel, in fact we quite like different here.
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Post by turkey on Apr 16, 2012 11:11:33 GMT
To reiterate something we are regularly pointing out on the forum: there are many and varied possible wfo designs, all of which will do a job and as a forum we will try and support anyone looking for help irrespective of the design they favour. Its not just about pompeii or barrel, in fact we quite like different here. good point well made, and that is what makes it so much fun to see other peoples ideas and designs take shape and the fruits of their labour
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Post by Terry Hardwood on Apr 16, 2012 16:56:47 GMT
If an oven has Zero Thermal Mass then the loaf of bread must be cooked with direct heat from fire. Never seen that before so will look forward to the photos.
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Post by slowfood on Apr 17, 2012 9:51:50 GMT
You don't need a high thermal mass oven or an over-sized heat source to cook pizza in a domestic situation. In fact, I suspect you need less fuel as there's much less material to heat up. The benefit of the thermal mass comes into play when cooking something slow say a shoulder of pork overnight, or you are baking bread, as this is done without an internal fire, using heat retained in the oven's thermal mass. The extra thermal mass and good insulation mean a slower cooling cycle. Surely sooner or later peeps would want to cook more than just Pizza in such a fantastic tool as a WFO, One of the joys of owning a WFO is to roast the christmas Turkey and I can't see this happening in a low mass oven. Sure however the unique feature of a stone oven over your oven in the kitchen is the 3 ways in which it heats the contents, Radiation=Fire, Convection= Steam/hot air and finally Conduction= Thermal Mass. Your oven in the kitchen cooks by Convection and Infa Red (With the grill on) But not so good for conduction, Compare a storage heater to another kind of heater,
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Post by tonyb on Apr 17, 2012 11:25:56 GMT
I think the unique aspect of a wfo is its unique social nature, rather than its cooking abilities and not everyone wants to be on Masterchef.
I'm sure you could cook a turkey or other (quick) roast, though its likely to be a bit more difficult and time consuming feeding the fire regularly.
The principle cooking method in a wfo is radiation, there is very little conduction, (though the bottom of the pizza cooks via conduction ie contact).
There's little if any difference between a storage heater and normal central heating radiator in terms of giving out heat: radiation and convection. the only difference being how you generate the 'heat'.
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Post by Fat Bob on Apr 17, 2012 13:46:15 GMT
I have previously posted pictures of the ZTM we use to cook bread and do what you would do in any oven. It is a converted gas oven with all insulation and gas pipes/burners removed.
The wood is burned beneath the oven in what was the plate warming cupboard.
The fire heats the bottom of the oven and the gasses escape around the sides and back of this inner oven/cooking area the exhaust gasses then exit at the top back of the oven.
It takes a few minutes to get up to heat - it does run on twigs and fallen branches.
The ZTM pizza oven is a handbuilt contraption which cooksa pizza directly in the exhaust gasses on a rotating table - a pizza takes a large handful of twigs or 3 kindling sticks to cook. Again it takes a minute or so to get up to heat.
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Post by Calaf on Apr 17, 2012 14:08:19 GMT
Is this it, Bob? Ingenious with the rotating base. Some convection also involved from the circulating hot gas.
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Post by Fat Bob on Apr 17, 2012 17:25:38 GMT
Yes, but it has been seen significant further modifications since that picture. We have altered and made the gas flow variable and added rare earth magnets to securely hold the tray to the rotating platform. Plus some other top secret additions as I am trying to flog the concept.
It is worth a few hours in the shed with an old washing machine to build yourself a pizza oven that uses very little fuel that gets up to heat quickly and gives a good wood smoked flavour.
This early model used a stick to rotate or spin the pizza but we have a more ingenious method of propulsion now. (It no longer spins on a bicycle pedal!)
It is useful being lightweight as if the weather is inclement it can be placed just outside the backdoor.
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Post by sofaboy on May 13, 2012 8:19:25 GMT
Bob. Do you have any photos of your zero mass oven?
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Post by sofaboy on May 13, 2012 8:24:27 GMT
Sorry Bob - have just found the photos
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Post by slowfood on Feb 9, 2013 22:36:58 GMT
Resurrecting this old thread, I need to build a lightweight oven ASAP, Since this thread was forgot ton did anybody work out the best way to build a strong lightweight oven (which would travel?) Thank you all
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