After seeing them in catalogs and hearing my neighbor talk about hers,
I bought a used steam canner and hit the web to find instructions. Lo
and behold, they're not considered safe.

I'd like to learn more. I can't find the text of the U California Davis
study (which I know U of Wisconsin disputes), or text of any other
study for that matter. USDA says not enough study of steam canners has
been done so they don't recommend them. In canning, I suppose "it's
unsafe because we don't know if it's safe" is reasonable, but I'm
hoping for better info. I found a ton of anecdotal comments - a lot of
people have very strong opinions both pro and con - but does anyone
know where there's text of actual non-urban-legend studies?

In past discussions in this group several people said that there's no
reason to use a steam canner when you can use BWB. I have a reason. It
takes 45 minutes for me to bring the big canner to a boil. I have a
garden that doesn't necessarily produce 7 jars worth of tomatoes,
pickles, or jam fruit at a time, but might have enough for two today
and three next week. Prepping small batches for hot pack is no problem,
but it's hard to justify the time and power usage to bring that huge
canner up to speed for a jar or two. I mentioned this to my neighbor,
who said that when someone gives her a bag of fruit, she just cans a
jar at a time easily with her steam canner.

If people have been steam canning for years, isn't there at least a
study comparing the percentage of people who get sick from steam
canners vs BWB canners? Has anyone seen one?

Kathy

"Kathy" wrote in message
oups.com...

If people have been steam canning for years, isn't there at least a
study comparing the percentage of people who get sick from steam
canners vs BWB canners? Has anyone seen one?

Now I'm totally confused. What exactly is BWB doing?

I thought the point of BWB was to create a good seal. The food is acidic
enough to not have to worry about botulism and the like, and basically the
concern was to prevent mold. You put hot food in hot jars and createa
vacuum that prevents mold spores from getting in and growing. In fact, I
thought I read here on rfp that the reason the inversion method is not
recommended isn't for safety reasons but to minimize the number of jars that
don't seal.

But if this isn't it, what does BWB canning do? Why wouldn't steam canning
or the inversion method or the old "put paraffin on jam" method (which I
still see occasionally even in fairly recent books) or the "put the jars in
a hot oven" method (which I've read about now and then) be safe?

I'm assuming of course that the cook is stringent about checking the quality
of the seal and refrigerating any jar that is questionable.

Anny

Anny Middon wrote:

"Kathy" wrote in message
oups.com...

If people have been steam canning for years, isn't there at least a
study comparing the percentage of people who get sick from steam
canners vs BWB canners? Has anyone seen one?


Now I'm totally confused. What exactly is BWB doing?

I thought the point of BWB was to create a good seal. The food is acidic
enough to not have to worry about botulism and the like, and basically the
concern was to prevent mold. You put hot food in hot jars and createa
vacuum that prevents mold spores from getting in and growing. In fact, I
thought I read here on rfp that the reason the inversion method is not
recommended isn't for safety reasons but to minimize the number of jars that
don't seal.

To minimize the number of jars that mold. I think full-sugar jelly is
the only thing that gets hot enough during cooking to kill any mold
spores that might drift into the jar as you fill it, or that are on the
underside of the lid.

But if this isn't it, what does BWB canning do? Why wouldn't steam canning
or the inversion method or the old "put paraffin on jam" method (which I
still see occasionally even in fairly recent books) or the "put the jars in
a hot oven" method (which I've read about now and then) be safe?

If you are canning high-acid foods, they are inherently safe and IMHO
you can process them however you like -- if you have a high tolerance
for throwing out occasional jars that spoil.

Best regards,
Bob

Z. wrote:
"zxcvbob" wrote in message


To minimize the number of jars that mold. I think full-sugar jelly is
the only thing that gets hot enough during cooking to kill any mold
spores that might drift into the jar as you fill it, or that are on the
underside of the lid.



If you are canning high-acid foods, they are inherently safe and IMHO
you can process them however you like -- if you have a high tolerance
for throwing out occasional jars that spoil.


Regarding sugar content, I don't think its a question of sugar assisting an
increase in temperature. Some where, some time ago I read that the amount of
sugar acts against bacteria because it acts as an increase in acid content
acid.

That's why I specifically mentioned mold. I don't think I've ever seen
a jar of jam or jelly that was spoiled with anyting other than mold on top.


Oven canning, according to the Ball Blue Book, processing in an oven is not
as effective as BWB because the dry heat does not penetrate in the same way
as the heat transfer from boiling water.
BWB is intended to render the high acid food safe for storage and
consumption. The "seal" is achieved once the internal temperature drops
below a point where the pressure of the water vapour exiting from the jar is
less that the exterior air pressure. You can demonstrate this by filling a
jar with boiling water and slipping on a lid, wait and you will hear it pop.

BWB vs steam. The difference is the temperature, it gets hotter in a
pressure canner than in a BWB.

Of course it gets hotter in a pressure canner. But at atmospheric
pressure, steam gets just as hot as boiling water. Anything you can
process in a boiling water bath, you should be able to process in a
steam bath (here comes the important part) if you can figure out how
long to process it.

Bob

Anny Middon wrote:
"Kathy" wrote in message
oups.com...

If people have been steam canning for years, isn't there at least a
study comparing the percentage of people who get sick from steam
canners vs BWB canners? Has anyone seen one?


Now I'm totally confused. What exactly is BWB doing?

I thought the point of BWB was to create a good seal. The food is acidic
enough to not have to worry about botulism and the like, and basically the
concern was to prevent mold. You put hot food in hot jars and createa
vacuum that prevents mold spores from getting in and growing. In fact, I
thought I read here on rfp that the reason the inversion method is not
recommended isn't for safety reasons but to minimize the number of jars that
don't seal.

But if this isn't it, what does BWB canning do? Why wouldn't steam canning
or the inversion method or the old "put paraffin on jam" method (which I
still see occasionally even in fairly recent books) or the "put the jars in
a hot oven" method (which I've read about now and then) be safe?

I'm assuming of course that the cook is stringent about checking the quality
of the seal and refrigerating any jar that is questionable.

Anny


My understanding is that the contents of the jar need to be heated to a
certain temperature all the way through ( in the jar with the lid on).
Water conducts the heat better than air does ( steam is water droplets
in air and in a steam canner ( as opposed to a pressure canner) does not
do that as well. Oven canning also uses air, not water to conduct the
heat to the jar. With jam/jelly the BWB is to seal the jar and make
sure that any molds in the air space cannot grow. Parafin does not do
that and may allow new spores to enter and grow.
Ellen

True, of course, but I wasn't referring to steam pressure canning. I
meant the evil kind of steam canning, in a plain steam canner - a
kettle-shaped top cover over a shallow steamer pan with a rack on it.
For a few jars of a high-acid food, it would be way easier to bring a
quart of water to a boil in that shallow pan and process the jars in
the trapped steam above it, than boil the gallons needed in the big BWB
canner.

I know the USDA doesn't approve. But I'm still looking for any real
research that's been done. It's such a sensible method that you'd think
someone would have tested it, proven conclusively that it does or
doesn't work, and published results. All I can find are opinions and
guesses.

Kathy

Kathy wrote:

True, of course, but I wasn't referring to steam pressure canning. I
meant the evil kind of steam canning, in a plain steam canner - a
kettle-shaped top cover over a shallow steamer pan with a rack on it.
For a few jars of a high-acid food, it would be way easier to bring a
quart of water to a boil in that shallow pan and process the jars in
the trapped steam above it, than boil the gallons needed in the big BWB
canner.

I know the USDA doesn't approve. But I'm still looking for any real
research that's been done. It's such a sensible method that you'd think
someone would have tested it, proven conclusively that it does or
doesn't work, and published results. All I can find are opinions and
guesses.

Kathy



Do you have a small pressure canner or cooker? When I get home, I'll
look up the procedure for using that for a BWB without having to totally
immerse the jars.

Bob

zxcvbob wrote:
Kathy wrote:

True, of course, but I wasn't referring to steam pressure canning. I
meant the evil kind of steam canning, in a plain steam canner - a
kettle-shaped top cover over a shallow steamer pan with a rack on it.
For a few jars of a high-acid food, it would be way easier to bring a
quart of water to a boil in that shallow pan and process the jars in
the trapped steam above it, than boil the gallons needed in the big BWB
canner.

I know the USDA doesn't approve. But I'm still looking for any real
research that's been done. It's such a sensible method that you'd think
someone would have tested it, proven conclusively that it does or
doesn't work, and published results. All I can find are opinions and
guesses.

Kathy



Do you have a small pressure canner or cooker? When I get home, I'll
look up the procedure for using that for a BWB without having to totally
immerse the jars.

Bob
If you don't totally immerse the jars it won't be a BWB
Ellen

ellen wickberg wrote:

zxcvbob wrote:

Kathy wrote:

True, of course, but I wasn't referring to steam pressure canning. I
meant the evil kind of steam canning, in a plain steam canner - a
kettle-shaped top cover over a shallow steamer pan with a rack on it.
For a few jars of a high-acid food, it would be way easier to bring a
quart of water to a boil in that shallow pan and process the jars in
the trapped steam above it, than boil the gallons needed in the big BWB
canner.

I know the USDA doesn't approve. But I'm still looking for any real
research that's been done. It's such a sensible method that you'd think
someone would have tested it, proven conclusively that it does or
doesn't work, and published results. All I can find are opinions and
guesses.

Kathy



Do you have a small pressure canner or cooker? When I get home, I'll
look up the procedure for using that for a BWB without having to
totally immerse the jars.

Bob

If you don't totally immerse the jars it won't be a BWB
Ellen


You fill it with water up to the shoulders of the jars, put on the
pressure lid with the vent open, and let the saturated steam take care
of the lids while the boiling water takes care of the jar contents.
Time it just like a BWB.

It's in a canning book I have at home, and it works well. I will look
up the reference when I get home. You'll have to decide for yourself if
it's too risky. (remember, we are talking about fruits and pickles and
spreads and acidified tomatoes -- the risk is losing jars to mold, not
losing your life to botulism.)

Bob

zxcvbob wrote:

ellen wickberg wrote:

zxcvbob wrote:

Kathy wrote:

True, of course, but I wasn't referring to steam pressure canning. I
meant the evil kind of steam canning, in a plain steam canner - a
kettle-shaped top cover over a shallow steamer pan with a rack on it.
For a few jars of a high-acid food, it would be way easier to bring a
quart of water to a boil in that shallow pan and process the jars in
the trapped steam above it, than boil the gallons needed in the big BWB
canner.

I know the USDA doesn't approve. But I'm still looking for any real
research that's been done. It's such a sensible method that you'd think
someone would have tested it, proven conclusively that it does or
doesn't work, and published results. All I can find are opinions and
guesses.

Kathy



Do you have a small pressure canner or cooker? When I get home, I'll
look up the procedure for using that for a BWB without having to
totally immerse the jars.

Bob

If you don't totally immerse the jars it won't be a BWB
Ellen

You fill it with water up to the shoulders of the jars, put on the
pressure lid with the vent open, and let the saturated steam take care
of the lids while the boiling water takes care of the jar contents.
Time it just like a BWB.

It's in a canning book I have at home, and it works well. I will look
up the reference when I get home. You'll have to decide for yourself if
it's too risky. (remember, we are talking about fruits and pickles and
spreads and acidified tomatoes -- the risk is losing jars to mold, not
losing your life to botulism.)

Bob

The Joy of Pickling has a "pasteurization" method I used last year for cuke
pickles. It involves a great deal of simmering water (up to the shoulders) and
relatively even temperature taking for about 30 minutes. I did notice a
slightly firmer pickle, but keeping the temp at 180F was a pain in the rear. If
it fell below, ya had to start all over. My tcw.
Edrena

The Joneses wrote:
zxcvbob wrote:


ellen wickberg wrote:


zxcvbob wrote:


Kathy wrote:


True, of course, but I wasn't referring to steam pressure canning. I
meant the evil kind of steam canning, in a plain steam canner - a
kettle-shaped top cover over a shallow steamer pan with a rack on it.
For a few jars of a high-acid food, it would be way easier to bring a
quart of water to a boil in that shallow pan and process the jars in
the trapped steam above it, than boil the gallons needed in the big BWB
canner.

I know the USDA doesn't approve. But I'm still looking for any real
research that's been done. It's such a sensible method that you'd think
someone would have tested it, proven conclusively that it does or
doesn't work, and published results. All I can find are opinions and
guesses.

Kathy



Do you have a small pressure canner or cooker? When I get home, I'll
look up the procedure for using that for a BWB without having to
totally immerse the jars.

Bob

If you don't totally immerse the jars it won't be a BWB
Ellen

You fill it with water up to the shoulders of the jars, put on the
pressure lid with the vent open, and let the saturated steam take care
of the lids while the boiling water takes care of the jar contents.
Time it just like a BWB.

It's in a canning book I have at home, and it works well. I will look
up the reference when I get home. You'll have to decide for yourself if
it's too risky. (remember, we are talking about fruits and pickles and
spreads and acidified tomatoes -- the risk is losing jars to mold, not
losing your life to botulism.)

Bob


The Joy of Pickling has a "pasteurization" method I used last year for cuke
pickles. It involves a great deal of simmering water (up to the shoulders) and
relatively even temperature taking for about 30 minutes. I did notice a
slightly firmer pickle, but keeping the temp at 180F was a pain in the rear. If
it fell below, ya had to start all over. My tcw.
Edrena





I've used that method, but I covered the jars. It works pretty well but
it's a PITA.

2¢

Bob

That's what I've seen too - people believe that steam doesn't heat the
jars as well as boiling water does. But does anyone know for sure or is
that just a guess? I found a reference to a UC Davis study that
purportedly found that a steam canner heated cold-packed jars of
applesauce, pickles, and tomatoes to 180 degrees even faster than BWB
did, but I can't find the text of that study online, just commentary by
someone who said she read it.

Kathy

"Kathy" wrote in message
oups.com...
After seeing them in catalogs and hearing my neighbor talk about hers,
I bought a used steam canner and hit the web to find instructions. Lo
and behold, they're not considered safe.


If people have been steam canning for years, isn't there at least a
study comparing the percentage of people who get sick from steam
canners vs BWB canners? Has anyone seen one?


I Googled this because I was interested. I suspect Kathy has already found
this article, but since I thought it was interesting, I'll post it:

http://www.wisc.edu/foodsafety/asset...fApril2005.htm

Home Processing of Tomatoes and Other Acid Foods in Flowing Steam and Hot
Water Bath Canners



The USDA does not recommend the use of steam canners for canning acid foods,
including fruits, acidified vegetables, and pickles because of a lack of
data demonstrating that the use of flowing steam in home canning is safe.
There are no published data on comparison of time-temperature relationships
for steam and hot water bath canners (boiling water canners). Neither steam
nor hot water canners are recommended for use in canning low-acid foods
(those with a pH above 4.6) such as meat, chicken and vegetables such as
corn, green beans and carrots.



Master food preservers, working with a staff scientist at the University of
California-Davis , conducted research to determine whether a steam canner
could be as safe as a hot water bath for home canning of acid foods.
Standard Ball ® canning lids were fitted so that thermocouples (thin wires
for measuring temperature, hooked to a recording devise) could be placed
inside canning jars. The researches tested canning of tomato juice, sliced
peaches, whole peeled solid packed tomatoes and applesauce to represent the
range of densities and texture of most home-canned foods. For each of these
foods, pint jars (quart jars were too tall for the steam canner and were not
tested) were filled with food, leaving 1/2-inch headspace, covered with the
prepared lids and placed into the canner. Water sufficient to cover the pint
jars by 1-inch was used in the water bath canner, and 3 pints of water were
used in the steam canner.



All items were cold-packed (cold food with cold liquid used), placed into
one of the two canner types, and the temperature was recorded during the
process. The process was divided into two stages: 'come-up' time (the time
for the water bath canner to reach 212 ° F - boiling; or for the steam
canner to vent steadily for 5 minutes - to purge all air from the canner);
and 'processing time', the time for the temperature inside the jars to reach
the target temperature of 180 ° F. A target temperature of 180° was selected
as a temperature which would destroy pathogenic bacteria as well as
acid-tolerant spoilage bacteria that may be present in acid foods.



Results: For each of the four products tested: tomato juice, peaches, solid
pack tomatoes and applesauce, the processing time for the stream canner was
equal to, or shorter, than the processing time for the standard boiling
water canner. The authors concluded that a steam canner can be accepted as a
safe method for processing acid foods.



Based on these results, will Wisconsin begin to recommend steam canners as a
safe alternative for processing acid foods? NO! And why not? Unfortunately,
the methods followed for this research did not mimic processes outlined in
the USDA Complete Guide to Home Canning . The USDA Guide contains a wealth
of home canning recipes that have been laboratory-tested for safety. The
results of the California study, while encouraging, can not be compared to
standard home canning practices.



For example, in the California study, while the jars were pre-heated, the
contents added to the jars were at room temperature, or colder, and cold
liquid, if necessary, was added. The USDA Guide specifies that liquid added
to jars, even those that are cold packed, must be hot/simmering. Adding cold
liquid to the jars would have affected the 'come up' time and does not mimic
standard practice. Furthermore, the processing time that the researchers
used in their comparison were not equivalent to those in the USDA Guide for
the products that they chose, so we have no real way to judge the validity
of these results. Unfortunately, it appears that the peer-review process
that led to acceptance of this work in a scientific journal failed to take
into account the standard methods for home canning. Although published just
this year, the work cited in this article was conducted in 1994. Changes in
the USDA Guide since 1994 may be one reason the research does not provide a
foundation for recommendations today. M. Samida, L. Geer, and G. York. 2005.
Home Processing of Tomatoes and Other Acid Foods in Flowing Steam and Hot
Water Bath Canners. Journal of Food Protection 25:178-181.

-----------------



I'm certainly not a scientist, which probably is why I don't understand the
conclusion. If steam canning brings room temperature food to the right
temperature point in the same amount of time as BWB canning, why wouldn't it
work with hot foods? Are they picking nits or am I missing some vital
scientific point here?



Anny

Anny Middon wrote:
"Kathy" wrote in message
oups.com...

After seeing them in catalogs and hearing my neighbor talk about hers,
I bought a used steam canner and hit the web to find instructions. Lo
and behold, they're not considered safe.


If people have been steam canning for years, isn't there at least a
study comparing the percentage of people who get sick from steam
canners vs BWB canners? Has anyone seen one?



I Googled this because I was interested. I suspect Kathy has already found
this article, but since I thought it was interesting, I'll post it:

http://www.wisc.edu/foodsafety/asset...fApril2005.htm

Home Processing of Tomatoes and Other Acid Foods in Flowing Steam and Hot
Water Bath Canners



The USDA does not recommend the use of steam canners for canning acid foods,
including fruits, acidified vegetables, and pickles because of a lack of
data demonstrating that the use of flowing steam in home canning is safe.
There are no published data on comparison of time-temperature relationships
for steam and hot water bath canners (boiling water canners). Neither steam
nor hot water canners are recommended for use in canning low-acid foods
(those with a pH above 4.6) such as meat, chicken and vegetables such as
corn, green beans and carrots.



Master food preservers, working with a staff scientist at the University of
California-Davis , conducted research to determine whether a steam canner
could be as safe as a hot water bath for home canning of acid foods.
Standard Ball ® canning lids were fitted so that thermocouples (thin wires
for measuring temperature, hooked to a recording devise) could be placed
inside canning jars. The researches tested canning of tomato juice, sliced
peaches, whole peeled solid packed tomatoes and applesauce to represent the
range of densities and texture of most home-canned foods. For each of these
foods, pint jars (quart jars were too tall for the steam canner and were not
tested) were filled with food, leaving 1/2-inch headspace, covered with the
prepared lids and placed into the canner. Water sufficient to cover the pint
jars by 1-inch was used in the water bath canner, and 3 pints of water were
used in the steam canner.



All items were cold-packed (cold food with cold liquid used), placed into
one of the two canner types, and the temperature was recorded during the
process. The process was divided into two stages: 'come-up' time (the time
for the water bath canner to reach 212 ° F - boiling; or for the steam
canner to vent steadily for 5 minutes - to purge all air from the canner);
and 'processing time', the time for the temperature inside the jars to reach
the target temperature of 180 ° F. A target temperature of 180° was selected
as a temperature which would destroy pathogenic bacteria as well as
acid-tolerant spoilage bacteria that may be present in acid foods.



Results: For each of the four products tested: tomato juice, peaches, solid
pack tomatoes and applesauce, the processing time for the stream canner was
equal to, or shorter, than the processing time for the standard boiling
water canner. The authors concluded that a steam canner can be accepted as a
safe method for processing acid foods.



Based on these results, will Wisconsin begin to recommend steam canners as a
safe alternative for processing acid foods? NO! And why not? Unfortunately,
the methods followed for this research did not mimic processes outlined in
the USDA Complete Guide to Home Canning . The USDA Guide contains a wealth
of home canning recipes that have been laboratory-tested for safety. The
results of the California study, while encouraging, can not be compared to
standard home canning practices.



For example, in the California study, while the jars were pre-heated, the
contents added to the jars were at room temperature, or colder, and cold
liquid, if necessary, was added. The USDA Guide specifies that liquid added
to jars, even those that are cold packed, must be hot/simmering. Adding cold
liquid to the jars would have affected the 'come up' time and does not mimic
standard practice. Furthermore, the processing time that the researchers
used in their comparison were not equivalent to those in the USDA Guide for
the products that they chose, so we have no real way to judge the validity
of these results. Unfortunately, it appears that the peer-review process
that led to acceptance of this work in a scientific journal failed to take
into account the standard methods for home canning. Although published just
this year, the work cited in this article was conducted in 1994. Changes in
the USDA Guide since 1994 may be one reason the research does not provide a
foundation for recommendations today. M. Samida, L. Geer, and G. York. 2005.
Home Processing of Tomatoes and Other Acid Foods in Flowing Steam and Hot
Water Bath Canners. Journal of Food Protection 25:178-181.

-----------------



I'm certainly not a scientist, which probably is why I don't understand the
conclusion. If steam canning brings room temperature food to the right
temperature point in the same amount of time as BWB canning, why wouldn't it
work with hot foods? Are they picking nits or am I missing some vital
scientific point here?



Anny




The primary thing that you and other new canners, plus some experienced
canners, miss is that the method is NOT USDA approved nor tested by
them. It has been the practice on this newsgroup for the 14 + years I've
been on it for experienced food preservers to only recommend the USDA
methods. Why? Because they have been PROVEN safe and, if you follow the
directions properly, will produce foods that are safe for human
consumption and that food should not promote foodborne diseases.

That being said, and I have been following this thread since it started,
you takes your chances and pays your prices. Now, go back and reread
what you've sent to the group. The scientific methodology followed in
the California test was not the methodology that USDA recommends. Some
readers of this group may make recommendations that include methods not
approved by USDA but not me.

George

Anny Middon wrote:

"Kathy" wrote in message
oups.com...
After seeing them in catalogs and hearing my neighbor talk about hers,
I bought a used steam canner and hit the web to find instructions. Lo
and behold, they're not considered safe.
If people have been steam canning for years, isn't there at least a
study comparing the percentage of people who get sick from steam
canners vs BWB canners? Has anyone seen one?

I Googled this because I was interested. I suspect Kathy has already found
this article, but since I thought it was interesting, I'll post it:

http://www.wisc.edu/foodsafety/asset...fApril2005.htm

Home Processing of Tomatoes and Other Acid Foods in Flowing Steam and Hot
Water Bath Canners [clipped article]
-----------------
I'm certainly not a scientist, which probably is why I don't understand the
conclusion. If steam canning brings room temperature food to the right
temperature point in the same amount of time as BWB canning, why wouldn't it
work with hot foods? Are they picking nits or am I missing some vital
scientific point here?
Anny

An interesting discussion Anny. I did not see any adjustments to altitude
however. As I understand it our air pressure is lighter up here, which could
conceivabley lower the temperatures and increase processing times. And water
boils at 208 in my neighborhood.
In Putting Food By: " In mid-October 1987, the Pennsylvania State University's
Center for excellence researched the ..." "...disappointing results..."
"...kill-power/lethality when it is treated as a substitute for the traditional
B-W Bath.
"Thermal tests showed that inner temperatures in jars of strong-acid foods
processed in this canner could reach the same temp in a BWB. Examining the
contents of the procesed jars showed, however that spoilage micro-organisms had
not been destroyed by atmospheric steam [this is the proper name for a steam
canner as opposed to a pressure steam canner- e]. Therefore, PFB assumes ...
this canner cannot be used with B-W Bath processing times; new times must be
worked out for the canner if it is to be safe; and the folkway procedures for
operating this canner that have been published casually and by cataloguers are
not only inadequate but potentially dangerous as well."
PFB believes that these steam canners will eventually be reserved for
"finishing" or sealing high acid foods only.
Hope this helps.
Jack, do we have some discussion or links here we could add to our FAQ?
Edrena