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Post by awclymm on Apr 10, 2017 9:59:53 GMT
Hi folks
I have a "Meditterani Royale" 100cm oven - it's great, but I often have some issues whereby the base of a pizza doesn't cook so well.
It's not so bad for the first pizza, but subsequent pizzas suffer more and more. The top and sides cooks well, and the oven temp. is usually around 400 degrees, so I can only assume that the base is losing (or not retaining) heat too quickly.
Would it help if I re-position the coals after I move them for cooking? I normally put them to the left hand side of the oven, but as this is quite a large oven it would be easy to reposition them at the back, or the side/back, or even in a horseshoe shape.
Or have I got a bigger issue with the base of the oven ?? (I really hope not!!)
Comments much appreciated.
Thanks, Andy
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Post by downunderdave on Apr 10, 2017 21:32:09 GMT
Hi folks I have a "Meditterani Royale" 100cm oven - it's great, but I often have some issues whereby the base of a pizza doesn't cook so well. It's not so bad for the first pizza, but subsequent pizzas suffer more and more. The top and sides cooks well, and the oven temp. is usually around 400 degrees, so I can only assume that the base is losing (or not retaining) heat too quickly. Would it help if I re-position the coals after I move them for cooking? I normally put them to the left hand side of the oven, but as this is quite a large oven it would be easy to reposition them at the back, or the side/back, or even in a horseshoe shape. Or have I got a bigger issue with the base of the oven ?? (I really hope not!!) Comments much appreciated. Thanks, Andy O Your problem is probably one of the following, you can do the eliminations. 1. Oven simply not hot enough. Pizzas should take around 2 mins to cook. 2. Floor is too thin which means there is insufficient thermal mass to store heat. The usual is around 2". 3. Fire on the side not maintained. It needs to be an active fire with flame, not just coals. 4. No, or inadequate insulation under the floor, resulting in heat loss into the supporting slab. 5. Floor too thick and taking too long to reach required temp. 6. Underfloor moisture reducing insulation value. |
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Post by awclymm on Apr 11, 2017 9:12:57 GMT
Dave Many thanks for the considered response - and based on your comments, I'm pretty sure that it's the insulation on the base of the oven that's the problem. The oven sits on a purpose built steel frame, as you will see in the picture below - but that means that there is nothing below the floor of the ovevn to provide addiational insulation.  I guess I need to find some sort of insulation layer to attach below the base of the oven in order to minimise heat loss - if anybody has any suggestions for suitable material that would be very helpful. Thanks again. |
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Post by downunderdave on Apr 11, 2017 21:29:06 GMT
Hi Andy,
I think you've found your problem. I don't know what sort of manufacturer would sell an oven with no under floor insulation. Maybe you should go back to them to see what they can offer you. 2" of calcium silicate insulation board is probably the most common material, but there are plenty of others. Does the oven have insulation over the dome? If not that will also impair its performance.
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Post by awclymm on Apr 12, 2017 7:13:20 GMT
Hi Dave
I'll look into it - but this was an expensive oven, and the build quality is excellent. The dome insulation is superb, even with the oven at full blast you can touch the outside surface comfortably. And having looked at the oven more closely, there is 9 cms of insulation between the cooking surface and the base.
Next time it is fired up I will check the temperature underneath with an infrared thermometer - this should tell me if I have a problem or not.....
Thx again, Andy
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Post by moonhead on Apr 12, 2017 22:09:46 GMT
Could be the actual thickness of the oven floor itself. It may have plenty of under floor insulation but if the floor thickness is thin with little thermal mass then it's not going to hold the heat for long. I've used a similar oven belonging to a friend, thin brick floor looses initial temp after two pizzas. You may just have to move the fire back over the cooking area to re heat.
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Post by downunderdave on Apr 13, 2017 0:15:18 GMT
9 cm should be plenty. As Moonhead has suggested and my point no. 2, your floor maybe too thin. You could try adding more floor tiles over the top of the existing ones, but you will need t cut them to fit the perimeter. When cooking pizza you need to fire for around 1.5-2 hrs to really soak the thing with heat (see point 1) and maintain an active flame on the side to maintain this high temperature.
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Post by oblertone on Apr 15, 2017 5:49:10 GMT
FWIW I have a similar but homemade arrangement and the underside of my oven gets to about 60c. I have no trouble cooking up to 70 pizzas (Max so far) on storage heater blocks over 25mm of vermiculite board, so I suspect Dave is right and your floor isn't holding heat.
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Post by awclymm on Apr 15, 2017 8:27:02 GMT
Thanks to all....
I will investigate adding some new flooring tiles / bricks to the base I think.
Could anybody please recommend the best material for this type of job? I'm keen to ensure a smooth surface when finished so the peel doesn't get caught, and I'm conscious that doing this inside an exisiting oven is going to be quite fiddly to say the least!
Cheers.
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Post by downunderdave on Apr 15, 2017 20:54:06 GMT
What is the thickness of the existing floor bricks? The reason I'm asking is that it is possible that your underfloor insulation could still be moist and therefore not insulating properly and drawing heat away from the cooking floor. This is a possibility especially if the manufacturer used perlcrete or vermicrete. 9 cm of insulation is quite thick and should insulate adequately, unless it's a dense material with a lower insulation value.This is a possibility as the oven does not appear to have a supporting slab. I think you need to take your complaint to the manufacturer who may be able to advise you how to rectify your problem.
However,If you want to make the floor thicker you could always remove the existing floor bricks and replace them with thicker ones (as I mentioned previously the usual is around 2"). If placing a second layer of brick over the existing floor you need to make sure you have good contact so the heat conducts well into the lower layer. The usual is to use a dry mix of 50/50 sand and powdered clay around 1/2" thick.This layer also works as a leveller. You need to use fire brick for the floor.
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Post by awclymm on Apr 16, 2017 9:02:28 GMT
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Post by awclymm on Apr 16, 2017 9:04:39 GMT
Here's another image:  |
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Post by moonhead on Apr 16, 2017 14:31:15 GMT
Hi Andy,
Looking at your image the floor may well be the same thickness as the oven wall. Whereas the chamber temperature will be maintained by the flame the floor will not. As Dave said a layer of firebricks on top of the existing floor will increase the ability of the floor to absorb and retain the heat longer. Vitcas should be a good source for a low quantity of firebricks, just decide how much additional thickness you want to add.
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Rick
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Post by downunderdave on Apr 16, 2017 21:07:19 GMT
The advertisement says it's made of clay, but the composition of the mix and whether it's been kiln fired or not is not disclosed. Most large pieces of any refractory material are subject to cracking because of the rapid and uneven temperature rise which is why most manufacturers use loosely laid smaller units that can expand and contract independently. You need thermal mass to store heat so the inner layer needs to be dense, but not too thick or it takes too long for the heat to soak through. As I said before the usual thickness of manufactured cast ovens for both floor and walls is around 2".
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Post by awclymm on Apr 17, 2017 8:47:37 GMT
Thanks again for the input.
I'm planning to lay a bed of red Vitcas fire bricks (30mm depth) on top of the existing clay (??) floor. I'm hoping this will resolve the issue!
I've never attempted anything quite like this before, so will speak with Vitcas about the best way to cut the bricks to shape and what sort of mortar I should use etc. etc. I'm hoping an angle grinder will do the job...
I'm also thinking that I will make a template of the necessary internal dimensions, pre-cut the bricks to that template and then hopefully they should fit snugly without too much bad language from me.
Cheers
Andy
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