Ordinary brick in the oven for even heat?
My oven is always much colder at the bottom than the top, and I've had issues cooking pretty much everything because of it. According to the gas guy there is nothing wrong with it, so I'm just trying to find ways to work around it.
So far I've tried putting a stoneware baking dish full of water on the bottom of the oven, and a big cast iron griddle. Neither have seemed to help much. I know there has been a lot of discussion about using unglazed tiles or a pizza stone in a gas oven to help keep the heat even. I have been unable to find the right tiles or a pizza stone that is small enough to fit in my tiny oven at a price that I can afford. So I am wondering about possible alternatives. Namely, ordinary house bricks, which I happen to have a stack of in the garden. I'm not interested in baking anything directly on them.
Would normal bricks contain harmful junk that would off-gas in an oven? Would wrapping them in foil mitigate this enough to make them safe? Would this idea even work at all?
The tile/ stone in the bottom of the oven is usually there to prevent burning the bottom of cookies and the like in small ovens. They stop the direct radiant heat from the oven's burner from "frying" things. I have a approximately 18" square by 3/8" thick tile in my home oven and it doesn't hurt. My rv oven has the same type of tile but cut down a little.
Many recipes say where in the oven to place the dish. Heat rises so unless you've got a convection oven, the top will be warmer. The bricks might have enough mass to keep things a little more even but they will take a very long time to come to temperature. I'd warm them outside in a gas grill the first few times. They might smell kind of ripe. Umm, do you have a dog?
Your board name, mandeRV, makes me wonder if you saw the tile idea on a recreational vehicle board. The glazed/ unglazed is meaningless unless you're cooking directly on the tile. Glazed are easier to clean. Tiles are fired at temperatures your home oven could never reach. Any off-gassing has already occurred. But if it makes you feel better; go for it. I'm far more bothered about dirty nasty ovens than any unlikely off-gassing.
My current glazed oven tiles, purchased at Home Depot, were made in Texas so I kind of doubt there was lead in them to begin with. I bought those to replace thinner tiles made... where ever.
"Daltile" out of Florida make little red tiles (maybe 6x6" and 1/2" thick called "pavers"?) that many folks do cook pizzas on directly. I use them in my pizza cooker made from a Weber kettle grill and a propane turkey cooker burner.
Drat, I stuffed myself yesterday and now I feel like pizza...
re: Friend of Bill W.
Thanks for the ideas. My user name doesn't have anything to do with RVs, though, unfortunately! It's just an old nickname plus my initial. More like ManderV. :)
At any rate the oven in question is an ordinary UK gas oven, albeit on the small side, and only 2 years old so it's not especially dirty or nasty. The bricks I'm thinking of, well, who knows what wildlife has done what on them but I'd clean them first of course. No gas grill, either, although I suppose I could try charcoal.
For whatever reason the usual DIY stores here in the UK seem to be short on saltillo or similar tiles, which is what I've seen mentioned in a few threads here and there (including Chowhound, for instance http://chowhound.chow.com/topics/299097).
Sorry, I didn't mean to imply you oven was dirty, its just that unglazed tiles are hard to clean. I think everything but bread is supposed to boil over, right? At least it seems that way in my ovens. So I wash them fairly often. Since the glaze is waterproof, as long as you don't soak it, the washed tile can go right back into the still warm oven to finish drying.
After you wash the bricks let them dry for several days and then warm slowly. Sometimes moisture left inside will "boil" and break the brick or make little chips fly off.
re: Friend of Bill W.
Yes, regular porous brick or stone could "explode" when heated, mostly due to the moisture trapped inside. If they survive the initial heating, perhaps they would be alright after that. A safer alternative would be firebricks, either whole or halves (usually called "splits"). These should be available from most masonry or fireplace suppliers, such as this one:
These will be safe to be heated to any temperature your oven can create. You could even bake right on them - I use them on my grill and bake pizzas right on the bricks.
Heat rises and most of the heat is going to be concentrated at the top and it couldn't possibly be "much colder" at the bottom especially if you say your oven is on the "small side".
Even if you put bricks in there, to pre-heat those bricks is going to take much longer than you think.
In many ovens you aren't going to get even heat from top/bottom and front/back. That's why they recommend you rotate the item you're baking halfway through.
You didn't say whether or not the temperature was accurate, just not even.
You may solve your problem by adjusting where the racks are when you put something into it .
Are the racks placed too high or too low?
You have a small oven and the top is very much colder than the bottom?
Hmmm.... It sounds like you're preventing the heat from properly rising/flowing around your baking dishes.
Maybe your bakeware is too big for your oven. The typical recommendation is to shoot for a clearance of around 2 to 3 inches, which is about 5 to 7 cm, between the walls of the oven and your baking dish.
Also, you may be trying to bake too much stuff in the oven at once. Your oven may not put out enough BTU's for the thermal mass you're cooking with, which translates to longer cooking times.
You might try a kiln shelf from a pottery or ceramic supply company. They are the same material as a pizza stone, but are available in many more sizes.
Be very careful heating normal red bricks since they are not designed for it and can explode as water turns to steam.
Wow, thanks for all the replies!
Friend of Bill, I'm sorry for the dirty oven comment--I meant for it to be a bit teasing! ;)
Anyway, with respect to the oven temp: yes, it is colder on the bottom. If I put the thermometer on the top or middle shelves it reads much warmer than the bottom shelf. The difference varies according to which gas mark it is on. I haven't systematically tested it yet, although that might be a fine project for the current frigid weather we are having. In any case it does not seem to get as hot as it is supposed to. The other day I experimentally turned it all the way up (gas mark 9, which is supposed to be 240 C or 475 F) and the temperature in the middle barely got up to 450 F after an hour, while the bottom rack was 400 F. So the calibration is obviously not right, but it did not come with any instructions for adjusting it.
As far as I can tell all the seals are fine, no burners are clogged, etc. Before I started the Thanksgiving baking bonanza I thoroughly cleaned the whole thing.
I tried the dish full of water on the oven floor trick again, since I didn't want to go out in the blizzard to look for firebricks and was leery of the garden bricks. It seemed to help a little bit. The pies and crust were all fine, although the turkey was a little under-done on the bottom. That was probably due to it being a little too large. I have to be careful about the size of cookware, etc. that I buy because standard sizes are usually too big.
Just for reference, the inside of the oven is 17.5 " front to back, 15.5" side to side, and 13" top to bottom. The way the oven is designed there is a burner on the bottom rear in the middle, and all the racks have a "stop" on the back that prevents the dishes from going back too far. This leaves a gap of about 5 inches between the back wall of the oven and the racks. I generally only cook one thing at a time unless there are multiple small dishes (like two miniature quiches or something like that).
I appreciate all the help in getting to the bottom of this problem and working around it! I've never had a gas oven before, but we were forced by circumstances to buy the smallest gas oven available when we bought this house. I wouldn't say that I am an especially accomplished cook but I've never had any particular problems turning out decent baked goods until I encountered this oven.
"Colder on the bottom..." I apologize for misreading your question.
Based upon the description of your oven, the burner is the middle on the bottom rear of the oven where the racks stop short leaving a gap of 5 inches between the back of the rack and the back wall, it sounds like the heat is shooting straight up the the top of the oven due to the 5 inch gap.
What you can try is to find something to redirect the heat forward, near the bottom rack to the heat will circulate from the bottom, forward and up. You need a baffle.
Maybe a cookie sheet that extends into that 5" space on the bottom shelf, or a double layer of heavy duty aluminum foil that's shaped into a curve that arcs the bottom back wall to the back of the bottom rack. You can pin that foil onto the rack. Actually, the foil can be flat instead of curved.
Basically, your goal is to direct the heat forward instead of letting it shoot straight up through the 5 inch gap.
Dave_c. might have the solution.
Quote: "You need a baffle.
Maybe a cookie sheet that extends into that 5" space on the bottom shelf, or a double layer of heavy duty aluminum foil that's shaped into a curve that arcs the bottom back wall to the back of the bottom rack. You can pin that foil onto the rack. Actually, the foil can be flat instead of curved." End.
You oven sounds just a little bit bigger than a recreational vehicle oven. On these, the burners are centered. This creates the burned bottom problem we use the tiles to solve. It sounds like your oven's manufacturer moved the burner to the rear to stop that. But the solution created another problem. I guess the hot air is supposed to rise up the "chimney" in the back, be pushed to the front then cool slightly and sink. Then it moves to the rear as more air in the back is heated and rises. Maybe sort of like a convection oven.
Just a silly question, are you sure you have all the parts? Is there a website you could see a picture of the oven all set up?
My first thought for a home brewed solution is a "tile" cut about 2" each way smaller than the oven bottom and placed 1/2 to 1" above the oven floor. I just use a few old lugnuts as spacers (they used to hold tires on a car). The important thing is to make sure there in an inch or so between the "tile's" edge and the oven walls on all 4 sides. If the spacers in front were a bit taller than those in the rear- so much the better. I used the word "tile" in my example but a piece of metal- like an old cut down cookie sheet would likely work just as well or even better.
I calibrate my ovens to give the desired temperature in the middle of the oven. I think I have some generic instructions for setting the temperature on gas ovens somewhere but this board doesn't have a private message function.