That could be the answer. Our oven is not huge, so to bake relatively large
breads I covered most of the bottom rack with the tiles. The space between
the bottom of the tiles and the heating element is probably about an inch.
I'll try allowing more space and see what happens.

> the Taylor thermometer...can only measure air temperature.

Doesn't the oven sensor measure air temperature, too? It sticks out into the
oven about 4 inches and it's located about 2 inches below the top of the
oven. How

I can't read the taylor through the door because the door glass is pretty
cloudy. But I've opened the door and taken the readings very quickly, both
with and without the tiles.

Thanks for your comments, Dick.

Pete

"Dick Margulis" > wrote in message
...
> Peter,
>
> The temperature that counts is the stable (adiabatic) temperature of the
> oven walls and the tiles, attained after adequate preheating (45 minutes
> sounds like enough).
>
> It may be that the oven sensor is doing a better job of measuring the
> wall temperature than the Taylor thermometer, which, after all, can only
> measure air temperature. Can you read the Taylor thermometer through a
> closed oven door, with the oven light on? (Here I am presuming, with no
> evidence, that the oven has both a light and a transparent door.) If so,
> so you find the same discrepancy?
>
> In that case, I would suggest that perhaps your tiles cover too much
> area relative to the heating element and therefore interfere with
> convection within the oven. How much clear space is there around the
> outside of the tiles? How much vertical space is between the heating
> element and the tiles? If either or both of these is too small, poor
> convection, especially if it is combined with the opening of the oven
> door, could account for the difference.
>
> Dick
>
> Peter Cook wrote:
>
> > Thanks for the many responses. To answer a few of the questions:
> >
> > 1. ">Is the tile against the ovens thermometer/sensor?" No, the tiles
are
> > on the bottom shelf of the oven, just above the bottom heating element,
and
> > the sensor is toward the top of the oven.
> >
> > 2. >Are you getting excellent bread?" Absolutely! (if I may say so
myself).
> > But of course we use the oven for all kinds of other things, too, and
many
> > of them need relatively accurate cooking temperatures. I suppose I could
put
> > the tiles in only when baking bread, but I've read of many people just
> > leaving them in and never heard of this problem before.
> >
> > 3. >"Can you place your thermometer next to the sensor?" The sensor and
the
> > thermometer are within an inch or so of each other. So this doesn't
appear
> > to be caused by temperature gradients within the oven or a convection
> > problem.
> >
> > 4. >"Did the oven manufacturer recommended that tiles be put into the
oven?"
> > Not as far as I know. The oven (Magic Chef, now owned by Maytag) was
here
> > when we bought the house, and I haven't found any indication one way or
the
> > other. But as I mentioned, I've read of many people doing this -
> > particularly bread bakers - and haven't heard of any problems.
> >
> > 5. >"How long is the oven on when you are noticing the temperature
> > difference?" 45 minutes or more. Once the oven gets up to temp, both
> > readings are stable and the difference doesn't change.
> >
> > So here I am, still wondering which reading to believe. I am tempted to
> > believe the Taylor, since it's known for its accuracy, and to assume
that
> > some weird phenomenon is throwing off the oven sensor. It's a shame,
really,
> > because the convenience of having an accurate sensor means we don't have
to
> > open the oven, check the thermometer, adjust the temp, check again, etc.
> >
> >
> > "Sidney" > wrote in message
> > news:BgYIb.97393$pY.4662@fed1read04...
> >
> >>Is the tile against the ovens thermometer/sensor? If so, the oven may
be
> >>"cutting off" prematurely due to the oven's sensor reaching the desired
> >>temperature on the side of the tile next to the heating element and
oven's
> >>thermometer. If you move the tile away from the temperature sensor in
the
> >>oven, it should stay "on" until the whole thing is up to temperature,
not
> >>just on one side of a single tile.
> >>
> >>Sid
> >>
> >>"Peter Cook" > wrote in message
> rthlink.net...
> >>
> >>>Anyone encounter this? My electric oven is lined with quarry tiles
since
> >
> > I
> >
> >>>bake a lot of bread. I use a Taylor thermometer to measure the temp,
and
> >>>when the tiles are in the oven, the thermometer reads significantly
> >
> > lower
> >
> >>>than the oven's digital readout after preheating. At lower temperatures
> >>>(300), the difference is about 60 degrees. At higher temperatures
(475),
> >>>it's about 25 degrees.
> >>>
> >>>When the tiles are removed, the readout and the thermometer are within
3
> >>
> >>or
> >>
> >>>4 degrees. I keep the thermometer close to the oven's temperature
> >
> > sensor,
> >
> >>so
> >>
> >>>they are measuring temperature at the same location in the oven.
> >>>
> >>>All readings are taken after the oven has preheated for at least 45
> >>
> >>minutes.
> >>
> >>>Obviously the heating characteristics of an oven change when there are
> >>
> >>tiles
> >>
> >>>involved. But why would they cause the thermometer and the oven's
> >>>temperature sensor to behave differently? And most importantly -- which
> >>
> >>one
> >>
> >>>is right??
> >>>
> >>>Pete
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >
> >
>