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Canning Techniques

Open-Kettle Canning

Inverted Jelly Jars

(Inverted Jelly Jars, n.d.)

 

 

After lids were affixed, jars were inverted and left to cool (Benson, 1913). Seals in this method were created by a vacuum as the jars cool.

Moldy Jelly

(Moldy Jelly, n.d.)

Why a Canning Jar Lid Will Come Unsealed

(Image courtesy of Katherine Grossman and granny-miller.com. Original image available at: http://www.granny-miller.com/why-a-canning-jar-lid-will-come-unsealed/) 

 

 

By 1936, the shortcomings of open-kettle canning were being identified.


The oldest canning method is the open-kettle method—heating food in an open kettle and pouring the boiling food into sterilized jars and then sealing the jars. Heating food in a kettle this way is quicker and more even than heating food in a jar. But the disadvantages to open-kettle canning seem to outweigh the one advantage. The chief difficulty is that food can so easily be contaminated while pouring it into the jars or sealing them.



--Breazeale, J. F. & Benson, O. H. (1936). Home canning methods. United States Department of Agriculture, Office of Information. Retrieved from https://archive.org/details/homecanningmetho1936unit