Author Topic: trouble with makeshift grill oven (Read 1939 times)

PizzaSuperFreak · « **on:** March 04, 2012, 11:37:48 AM »

please help! my pizzas are burning!

ok - so i have the following setup:

1) 2 layers of regular aluminum foil directly on grill
2) 2 layers of unglazed quarry tiles
3) firebricks for support of...
4) 2 layers of approximately 1mm galvanized steel plates (oddly shaped - but it was all home depot had - found in the roofing section)

the reason for the firebricks and steel plates was after doing some reading on this site it seems that strong steel plates are a good conductor of heat and are used to cook on. i thought that floating them atop the tiles would make a nice reflective surface for cooking the top of the pizza.

also the foil underneath the tiles was due to the fact that my grill was getting the tiles too hot compared to the oven temp.

all in all my project is a failure because still my 'floor' is too hot compared to the oven temp. i typically let it heat up for about 30-45 minutes and measure with a laser thermometer for the 'floor' which usually measures at that point at around 550. my grill thermometer reads at that point around 550 to 600.

still for some reason the bottom of the pie is getting burnt and i typically have to rescue the pizza by putting it on a cold pizza tray to finish cooking the top.

does anybody have any ideas or suggestions?

any help is appreciated.

buceriasdon · « **Reply #1 on:** March 04, 2012, 12:18:06 PM »

I don't have much time right now for a complete reply but my friend that steel being galvanized when heated can give off some poisonous gas. You should be ok as there is no direct heating of the steel but I'd look for something else. Do you have a IR gun to measure something other than air temp?

Bill/SFNM · « **Reply #2 on:** March 04, 2012, 01:15:57 PM »

Quote from: PizzaSuperFreak on March 04, 2012, 11:37:48 AM

does anybody have any ideas or suggestions?

any help is appreciated.

What's in your dough? Sugar, milk, even oil can be the source of burning on the bottom.

PizzaSuperFreak · « **Reply #3 on:** March 04, 2012, 01:37:02 PM »

Quote from: buceriasdon on March 04, 2012, 12:18:06 PM

I don't have much time right now for a complete reply but my friend that steel being galvanized when heated can give off some poisonous gas. You should be ok as there is no direct heating of the steel but I'd look for something else. Do you have a IR gun to measure something other than air temp?

wow - thanks for the heads up. i had no idea. i'll be getting rid of that then. plus it didn't seem to help anyway.

i do have a laser (ir) thermometer which i mentioned in my post. the tiles read at about 550 when i put the pizza in. and the grill thermometer reads at about 550 to 600. i'd imagine that when i open the grill, even being careful not to open it all the way, it releases much of the air heat.

PizzaSuperFreak · « **Reply #4 on:** March 04, 2012, 01:38:28 PM »

Quote from: Bill/SFNM on March 04, 2012, 01:15:57 PM

What's in your dough? Sugar, milk, even oil can be the source of burning on the bottom.

well, i'm not quite the measurement man, i go more on feel than anything. but it's fairly high-hydration dough (sticky), and i did put a couple tablespoons of olive oil plus maybe a teaspoon of sugar. that's a great thought though. i'm sure that has a lot to do with the burning.

thanks.

shuboyje · « **Reply #5 on:** March 04, 2012, 04:04:41 PM »

I just wanted to second the suggestion to get rid of that galvanized flashing and add that those are standard house bricks, not fire bricks. Doesn't really matter for your use, but if you tried to do other things with them as if they were fire bricks they would probably fail pretty quickly.

PizzaSuperFreak · « **Reply #6 on:** March 04, 2012, 05:24:44 PM »

Quote from: shuboyje on March 04, 2012, 04:04:41 PM

I just wanted to second the suggestion to get rid of that galvanized flashing and add that those are standard house bricks, not fire bricks. Doesn't really matter for your use, but if you tried to do other things with them as if they were fire bricks they would probably fail pretty quickly.

Wow I feel dumb. It did say fire bricks on the sign. Maybe they were mislabeled?

Thanks for the other heads up. I guess I'm back to the drawing board.

PizzaSuperFreak · « **Reply #7 on:** March 04, 2012, 10:10:01 PM »

Well. Thanks for your suggestions. Tonight it made a huge difference to exclude the oil and sugar. Also the temps were better as I waited about 45 minutes and the floor got to a very solid 550 while the air temp seemed to hold at 600 at least according to my ir thermometer and the grill thermometer.

Pizza took just over 5 min to cook and turned out good but of course no leopard spots ot anything at those low temps. Maybe I'll try removing the foil and see what happens with a longer preheat time.

dirk3000 · « **Reply #8 on:** March 05, 2012, 08:18:49 AM »

The stone to use for direct contact baking should always be a little porous, so it can absorb moistures that come out during the cooking. Otherwise they're trapped between the surface and the dough and start sticking and burning black.
You can check the stone's properties by pooring a little water on it, a spoon full or so, and watch how long it stays there before being absorbed. It should be absorbing it before your eyes, if it stays on the surface it's too dense.

PizzaSuperFreak · « **Reply #9 on:** March 05, 2012, 08:24:21 AM »

Quote from: dirk3000 on March 05, 2012, 08:18:49 AM

You can check the stone's properties by pooring a little water on it, a spoon full or so, and watch how long it stays there before being absorbed.

good suggestion. do u mean i should pour the water when it's cold or heated? i assume cold as heated should of course evaporate.

dirk3000 · « **Reply #10 on:** March 05, 2012, 08:42:38 AM »

Yes, cold.

PizzaSuperFreak · « **Reply #11 on:** March 05, 2012, 08:45:04 AM »

Quote from: dirk3000 on March 05, 2012, 08:42:38 AM

Yes, cold.

awesome. i just helped to increase your posts to 14!

dirk3000 · « **Reply #12 on:** March 05, 2012, 08:50:02 AM »

Hahhaha, great, thanks

Yeah, we support eachother here in every way

PizzaSuperFreak · « **Reply #13 on:** March 05, 2012, 09:30:37 AM »

ok, i just tried the h2O test. the water just beaded up and sat there. i tried to rub it into the tiles but it just sorta smeared around.

i guess this isn't as porous as i thought.

dirk3000 · « **Reply #14 on:** March 05, 2012, 10:09:45 AM »

Okay. So that's also what happens with liquids wanting to come out the bottom of the pizza, but because they're trapped between two surfaces they can't evaporate so they will char (not sure if that's the right word in english) and fuse with the surface.

Terracotta is a common choice for the purpose of cooking on it, so maybe you can find some bricks or tiles (unglazed). But do the h20 test on them too, cause some types are of higher density then others.
And the quarry tiles can also replace the upper steel plate, with some support of metal strips.

Bill/SFNM · « **Reply #15 on:** March 05, 2012, 10:35:02 AM »

Quote from: dirk3000 on March 05, 2012, 10:09:45 AM

Okay. So that's also what happens with liquids wanting to come out the bottom of the pizza, but because they're trapped between two surfaces they can't evaporate so they will char (not sure if that's the right word in english) and fuse with the surface.

What liquids are coming out of the bottom of a pizza crust that cause charring?

PizzaSuperFreak · « **Reply #16 on:** March 05, 2012, 11:08:46 AM »

Quote from: Bill/SFNM on March 05, 2012, 10:35:02 AM

What liquids are coming out of the bottom of a pizza crust that cause charring?

my guess is he meant steam?

Bill/SFNM · « **Reply #17 on:** March 05, 2012, 11:13:24 AM »

Quote from: PizzaSuperFreak on March 05, 2012, 11:08:46 AM

my guess is he meant steam?

Never seen steam cause charring.

PizzaSuperFreak · « **Reply #18 on:** March 05, 2012, 11:17:36 AM »

Quote from: Bill/SFNM on March 05, 2012, 11:13:24 AM

Never seen steam cause charring.

perhaps he meant oil then? i've since removed oil or sugar from my recipe. this helped alot.

Bill/SFNM · « **Reply #19 on:** March 05, 2012, 11:23:22 AM »

Oil coming out of the bottom of the crust? Never seen that.

The reason oil can be a cause of burning is that it tranfers heat more effectively. I cook all the time on non-porous surfaces such as a steel plate without experiencing burning. The materials you are using in the way you are using them may need a lot of tweaking, but as mentioned in my first response to you, I think your dough ingredients may be the more immediate problem.