On 2018-07-11 8:09 PM, Terry Coombs wrote:
> On 7/11/2018 3:58 PM, songbird wrote:
>> Terry Coombs wrote:
>>> Â* Â* We processed another batch of pickles today , and 3 jars broke in
>>> the
>>> steam processor . First batch we lost one . These are not-new wide mouth
>>> jars , and they're breaking near the bottom . They're not overfilled ,
>>> contents just up to theÂ* line below the threads . We've never had a
>>> bottle break before and wonder if these have defects or just what the
>>> problem might be .
>> Â*Â* i'm not sure what a steam processor might be, but
>> we've never had problems with any of our jars
>> breaking and i go from room temperature to pouring
>> boiling brines in over the cucumbers and beans and
>> no breaks.Â* i used to pre-heat them by filling with
>> hot water and letting them sit for a minute or two.
>> i think the key is to not go from freezing to
>> boiling all at once.
>>
>> Â*Â* we oven can, only a few have broken during that
>> stage, a missed crack in the jar i'm sure since
>> we've done many thousands of pints/quarts over
>> the years.
>>
>> Â*Â* do you have a spacer or screen or something in
>> the bottom to keep the heat from going directly
>> from the pan to the jars?
>>
>> Â*Â* maybe post a note to the preserving newsgroup...
>> a few people still read there.
>>
>>
>> Â*Â* songbird
>
> Â* This unit is a (relatively) shallow pan that holds boiling water ,
> with a plate full of holes to let the steam thru . The top cover is deep
> enough that it clears quart jars (but not 1/2 gal IIRC) . The jars are
> exposed only to steam , no direct contact with boiling water . The unit
> hadn't gotten up to temp - no steam coming from the vent - when they
> broke . As songbird suggested , occasionally a bad batch of jars gets
> thru .


I often use a method my mother used to use. Put the jars in a large pan
or pot, add water and crank up the heat to bring the water to a boil.
The heat forces the air out of the bottles so when you turn the burner
off there is a vacuum in the jars that sucks the hot water up into them.
You have to time things so that the jars are ready when the jam or
jelly is ready to go in.
My other method is to wash the jars thoroughly and set them upside down
on a cookie sheet in the oven. Crank the hear up to about 250, which is
hot enough to kill anything that would be killed by boiling water. That
also leaves less than 30 degrees difference between the hot jars and
cooked jams going into them, not enough to break the glass.