Jeff Miller wrote:
> an oven rack thermometer
>
> Eh. I don't see the point, myself. If the bread's not baking through or the
> crust isn't dark / crispy / whatever enough, just adjust the dial a bit next
> time.
>
Oven thermostats, to be kind, suck rocks. Most are off by considerable
amounts, and many vary. So, you set your oven to 350F and the next
think you know, your bread has turned to mahogany (the phrase one of my
employees used to describe the bread when he burned it. He's a used car
salesman now.) The oven shoots to 500, drops to 250, and then climbs to
450. I've seen oven temperatures fluctuate all over the place.

Using an oven thermometer lets you know what is really happening, and
when you need to call the repairman.

Mike

--
Mike Avery mavery at mail dot otherwhen dot com
part time baker ICQ 16241692
networking guru AIM, yahoo and skype mavery81230
wordsmith

A Randomly Selected Thought For The Day:
Don't worry if you're a kleptomaniac,
you can always take something for it.

"Mike Avery" > wrote in message news:mailman.7.1176482550.1838.rec.food.sourdough@ mail.otherwhen.com...

> Using an oven thermometer lets you know what is really happening, and
> when you need to call the repairman.

Where is the FAQ that tells how to find a repairman for oven thermostats?

"Mike Avery" > wrote in message news:mailman.7.1176482550.1838.rec.food.sourdough@ mail.otherwhen.com...

> Oven thermostats, to be kind, suck rocks. Most are off by considerable
> amounts, and many vary.

The kind I have in my old Kenmore gas range is very reliable, and quite
accurate, and, if not, is adjustable, though it has been difficult to find out
how it works and how it is adjusted. Furthermore, it has required, at rather
long intervals, to be disassembled for the purpose of cleaning its set of
electrical contacts. I found out by asking questions at r.f.s. that it, generically,
is a "millivolt control" which means it relies on current generated by a
pilot-flame-heated thermocouple to actuate the solenoid that opens the
gas valve when a heating cycle is called for. The regulation is quite fast,
with the on-off cycles lasting about 10 seconds at bread-baking temperatures,
and so precise that the fluctuation could not be noticed with a conventional
oven thermometer (though amounting to several Fahrenheit degrees when
recorded with a thermocouple thermometer). There is no doubt that the
recorded temperature depends on where in the oven the temperature sensor
is placed.

The opinion of the repair man is that the stove is too old and should be
replaced. I think it was made in the 1950's. It is quite likely that the elements
of the thermostat could not be replaced. For one thing, the thermal sensor is
probably based on the expansion of liquid mercury, which is abhorred by
the protectors of the environment (who, incidentally, do not know shit
about protecting against carbon and military).

So it goes!

--
Dicky

"Dick Adams" > wrote in message
...

"Mike Avery" > wrote in message
news:mailman.7.1176482550.1838.rec.food.sourdough@ mail.otherwhen.com...

> Oven thermostats, to be kind, suck rocks. Most are off by considerable
> amounts, and many vary.

The kind I have in my old Kenmore gas range is very reliable, and quite
accurate, and, if not, is adjustable, though it has been difficult to find
out
how it works and how it is adjusted. Furthermore, it has required, at
rather
long intervals, to be disassembled for the purpose of cleaning its set of
electrical contacts. I found out by asking questions at r.f.s. that it,
generically,
is a "millivolt control" which means it relies on current generated by a
pilot-flame-heated thermocouple to actuate the solenoid that opens the
gas valve when a heating cycle is called for. The regulation is quite fast,
with the on-off cycles lasting about 10 seconds at bread-baking
temperatures,
and so precise that the fluctuation could not be noticed with a conventional
oven thermometer (though amounting to several Fahrenheit degrees when
recorded with a thermocouple thermometer). There is no doubt that the
recorded temperature depends on where in the oven the temperature sensor
is placed.

The opinion of the repair man is that the stove is too old and should be
replaced. I think it was made in the 1950's. It is quite likely that the
elements
of the thermostat could not be replaced. For one thing, the thermal sensor
is
probably based on the expansion of liquid mercury, which is abhorred by
the protectors of the environment (who, incidentally, do not know shit
about protecting against carbon and military).

So it goes!

--
Dicky

Just how is an oven thermometer tested for accuracy and repeatability and if
it's off how is it calibrated ?

Bill

"bill" > wrote in message ...

> Just how is an oven thermometer tested for accuracy and
> repeatability and if it's off how is it calibrated ?

A glass thermometer with a mercury column can be a fine
temperature standard provided it is properly calibrated by
its manufacturer.

Such could be used from time to time to check the accuracy
of an ordinary (bimetallic) oven thermometer, which is a
more practical device inasmuch as a glass thermometer is
hard to read through an oven door.

A more elegant solution for studying oven temperature is a
thermocouple thermometer calibrated at two points, like
melting ice in distilled water at known atmospheric pressure,
and melting pure metal, like bismuth or tin. Of course, you
would probably want also to use a data-logging device if
you went that far.

For most people, the most practical solution would be to note
the thermostat setting that does the job best, and use that setting.
Not to worry until a poor result is got.

--
Dicky

> Dick Adams wrote:
> [...]
> A more elegant solution for studying oven temperature is a
> thermocouple thermometer calibrated at two points, like
> melting ice in distilled water at known atmospheric pressure,
> and melting pure metal, like bismuth or tin. Of course, you
> would probably want also to use a data-logging device if
> you went that far.
> [...]

If you want to be fanatic about it [not that anyone on this list would
do that ;-) ] you can order an Omega Engineering catalog and find
multichannel thermocouple dataloggers with certified stainless-encased
probes for $200 US up to $3000.

But the interesting thing to me is that as far as I can tell the
$50-$100 thermocouple thermometers being sold in kitchen stores today
are basically the industrial/lab thermometers of 10 years ago with less
rugged packaging and fewer features. I know back in the 80s we would
have been quite happy in our process plant chem lab with the units that
the kitchen catalogs sell for $50 today.

sPh