When canning why is it so important to process the product in a "hot
water bath" or a "pressure canner"? Both use boiling hot water to
heat the jars and their contents producing pressure which becomes a
vaccuum when they cool.

Why couldn' this be accomplished in a dry heat environment like an
oven set at a temperature higher than the boiling water?

The most inconvienient thing about canning is waiting for the huge pot
of water to come to a boil. I have a convection oven and could put
alot more jars in the oven than can fit in the pot. Also I could use
the oven's time setting to heat the jars for the allotted time and not
have to be there to pull them out of the water.

Why is the water neccessary? Just curious at this point.

Sincerely,
-Stuart Peddazzo....please, call me Stu!

not sure if the rubber seals would do well in a dry heat enviroment

Tim


"Stuart Pedazzo" wrote in message
...
When canning why is it so important to process the product in a "hot
water bath" or a "pressure canner"? Both use boiling hot water to
heat the jars and their contents producing pressure which becomes a
vaccuum when they cool.

Why couldn' this be accomplished in a dry heat environment like an
oven set at a temperature higher than the boiling water?

The most inconvienient thing about canning is waiting for the huge pot
of water to come to a boil. I have a convection oven and could put
alot more jars in the oven than can fit in the pot. Also I could use
the oven's time setting to heat the jars for the allotted time and not
have to be there to pull them out of the water.

Why is the water neccessary? Just curious at this point.

Sincerely,
-Stuart Peddazzo....please, call me Stu!

In article ,
Stuart Pedazzo wrote:

When canning why is it so important to process the product in a "hot
water bath" or a "pressure canner"? Both use boiling hot water to
heat the jars and their contents producing pressure which becomes a
vaccuum when they cool.

Why couldn' this be accomplished in a dry heat environment like an
oven set at a temperature higher than the boiling water?

The most inconvienient thing about canning is waiting for the huge pot
of water to come to a boil. I have a convection oven and could put
alot more jars in the oven than can fit in the pot. Also I could use
the oven's time setting to heat the jars for the allotted time and not
have to be there to pull them out of the water.

Why is the water neccessary? Just curious at this point.

Sincerely,
-Stuart Peddazzo....please, call me Stu!

Maybe this will help some, Stu.
http://www.uga.edu/nchfp/how/general...commended.html
I cook the jars while I cook whatever I'm planning to jar and process.
I've got the timing worked out pretty well with experience. I guess I
don't notice anything about waiting for the jars to boil - it's just a
part of what I do and I am accustomed to it.
--
-Barb, Mother Superior, HOSSSPoJ
http://web.mac.com/barbschaller
http://jamlady.eboard.com

"Stuart Pedazzo" wrote in message
...
When canning why is it so important to process the product in a "hot water
bath" or a "pressure canner"? Both use boiling hot water to
heat the jars and their contents producing pressure which becomes a
vaccuum when they cool.

Why couldn' this be accomplished in a dry heat environment like an
oven set at a temperature higher than the boiling water?

The most inconvienient thing about canning is waiting for the huge pot
of water to come to a boil. I have a convection oven and could put
alot more jars in the oven than can fit in the pot. Also I could use
the oven's time setting to heat the jars for the allotted time and not
have to be there to pull them out of the water.

Why is the water neccessary? Just curious at this point.

Sincerely,
-Stuart Peddazzo....please, call me Stu!

Stu - A good seal does not a preserved product make.
Preserving food is a balancing act to prevent initial infection, prevent
growth, and prevent byproducts (spores & toxins). We do this by acidity,
salinity, dehydration, freezing, alcohol, and/or heat. And some compounds
like pectin and sugar. Not mentioning that polysyllabic stuff the commercial
people use. And clean, sealable containers.
Acid foods can be safely canned at a lower temperature then
nonacid foods. *Boiling* water bath processing has been extensively
tested to ensure it's common use. Ditto with pressure canning (provided
one has one's gauges tested annually), what with the increased
atmospheric pressure created, can reach higher temperatures than
boiling water, for your nonacid foods. Steaming canners have not been
adequately tested IMHO and others.

Why couldn' this be accomplished in a dry heat environment like an
oven set at a temperature higher than the boiling water?

Everybody knows that home ovens/gauges are notoriously unreliable
and uneven heating appliances. I think there are some folk using this
method, but it is not recommended. The mason jars and lids are
designed to be used in water canners. And high heats just aren't
recommended or necessary for some foods.

The most inconvienient thing about canning is waiting for the huge pot
of water to come to a boil. I have a convection oven and could put
alot more jars in the oven than can fit in the pot. Also I could use
the oven's time setting to heat the jars for the allotted time and not
have to be there to pull them out of the water.

Face it - all canning is inconvenient, it's easier and probably cheaper for
most of us to buy at the store. But I like mine better & I feel it's more
healthful and it's fun.
I have a 33 gal "steamer" that I use for a BWB on two burners. Filled with
water a little over half, I can do a dozen half pints on one layer alone.
It also accomodates quarts, which some stockpots won't do.
I find that if I _plan_ well, it's actually very efficient and retains more
heat, comes to a boil quicker and is faster than canning 6 jars at a time.
Does that it for you? Visit our FAQ, it's got lots of links and stuff with
all the scientific data.
Edrena

Alan Moorman wrote:

I believe that using water provides automatic temperature control for
the process. Water boils at 212 deg (f) and given that, and a time
period, the process is automatic and works to process the food
safely.

I'd rephrase a bit with ".... [w]ater boils at a constant temperature
depending on altitude...."

B/

"Brian Mailman" wrote in message
...
Alan Moorman wrote:

I believe that using water provides automatic temperature control for
the process. Water boils at 212 deg (f) and given that, and a time
period, the process is automatic and works to process the food
safely.

I'd rephrase a bit with ".... [w]ater boils at a constant temperature
depending on altitude...."


DEPENDING ON PRESSURE

Higher altitude is lower pressure. You can boil water at room temperature
if
you subject it to a vacuum.

This is in fact the principle behind the pressure canner, and is why the
pressure
canners with simple weighted or jiggle guages are dangerous at high
altitude. Those canners
have a fixed pressure adjustment - the weight of the guage - which is
calibrated
at sea level. Pressure canners with dial guages have a guage that reads the
pressure
differential between atmospheric pressure and the pressure inside the
canner,
so as atmospheric pressure drops the higher you go, the guage will naturally
read a higher pressure than what you really need to have inside the canner.
Thus,
you have to adjust the pressure upward in the canner to compensate.

Ted

"Stuart Pedazzo" wrote in message
...

Why couldn' this be accomplished in a dry heat environment like an
oven set at a temperature higher than the boiling water?

Heat transfer is much more efficient in water than in air. I can keep my
armin a 212 degree oven much longer than I can immersed in a 212 degree pot
of boiling water. Same thing happens with the jars. I think we discussed
this a year or so ago.

The most inconvienient thing about canning is waiting for the huge pot
of water to come to a boil.

I start with the hottest water I can run in my tub to fill the pot. Put it
on the stove with a lid and turn the burner up to high. By the time my food
prep is done, the water is boiling.

Dave