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Jams, Jellies: Home Preserving: What's Wrong With Paraffin and Inversion Canning Methods?

Old time canners, such as those who canned using methods prior to the 1970's frequently question the need to use a water bath canner to process the sealed jars, particularly for jams and jellies.  They also often use paraffin as a sealing wax.  So... what's wrong with this? Well, let's look at what they did (and some still do...)

How did great-granny (1940's - 1960's) make jam?

Here's the olde tyme method:

  1. mush up some berries,
  2. add sugar,
  3. cook it, stirring it constantly to keep it from burning, until it thickens.  This could take 30 minutes.
  4. Then ladle it into clean jars.
  5. Melt some paraffin (wax) and ladle this on top of the jam in the jars.
  6. set to cool and screw a lid onto each jar.
  7. Then when you use it, try to pick the wax out of the jam.

How did granny (1960-1980) make jam?

The next generation updated the process once they heard about the Ball ring and lid method.  Unfortunately, many of them never read the instructions nor took a course ion food safety..

  1. mush up some berries,
  2. add sugar,
  3. cook it, stirring it constantly to keep it from burning, until it thickens.  This could take 30 minutes.
  4. Then ladle it into clean jars.
  5. Put a clean lid on the jar and screw the lid down
  6. Invert the jar (turn it upside down) and wait for it to cool.
  7. When the contents cool, they will contract (shrink in volume) and suck the lid down.  Granny believed this meant the contents were sterile.  Granny obviously never took a basic course in biology...

What's wrong with either of these methods?

Paraffin

Have you ever melt paraffin on your stove?  If you have, I can say with certainty that at some point you've burned yourself and probably started a small fire. Candles are made of wax.  It burns.  And doesn't reliably form a seal.  And if it does, the seal breaks easily. And then you pick wax out of the jam.  Seriously?

No water bath?

Even in the second method (inversion), the jars full of presumably "hot" jam are exposed to the atmosphere and THEN sealed and inverted.  So, let's play microbiologist for one second.  Air contains... spores!  Yes, inactive little "seeds" of things like clostridium botulinium, commonly known as botulism.  These spores land on the surface of the "hot" jam.  How hot?  Well certainly no higher than 212 F (100 C), the boiling point of water, and probably far cooler, especially on the surface. 

What temperature do you think it takes to substantially kill or reduce the number of spores?  Would you have guess above 240 F?  And even then it may take 20 minutes or more at that temperature.  Commercial processers use high pressure canning machines to reach far higher temperatures, long enough to accomplish this.

Net result?

Granny and her mother had a lot of jars spoil, certainly a lot more than someone using a jar, lid and ring and a water bath.  Not to mention burns and kitchen fires.  And a fair amount of jam that is unusable because it has wax floating in it.  Illness and fatalities?  Hard to say.  Probably not many because jams and jellies inherently prohibit the growth of most bacteria due to their high sugar and acid content.  But if these methods are used on things like corn, beans, tomatoes... that's far more dangerous and there are many documented cases of fatal food poisoning from these when canned like this at home.

What should you do?

. It's actually quite simple:

  1. Follow lab tested recipes, not just any found on the internet.  Credible sources are the USDA, universities, state extension services the Ball Blue Book and this website (PickYourOwn.org) as we use only these lab tested recipes are the basis for ours.  We simply add photos and addition explanatory text to make them easier to understand and follow. The complete list of all canning recipes is found on this page.
  2. Use a water bath or pressure canner, as appropriate to the recipe.That simply means immersing the sealed jars in boiling water (or in a pressure canner) for the time required in the recipe.  The recipe will explicitly state which canner to use.
  3. Do not modify recipes, except as they explicitly state you may.
  4. See this page for the links to the approved jams and jelly recipes and
    this page for jams and jelly questions and answers

More information:

Inversion canning:

The USDA and many, many universities have warnings against the use of this method (see the bottom of this page for references).  Here's a typical statement, from the University of Georgia:

"An old out-dated method of canning - the open-kettle method - is now considered unsafe. In this method, foods were heated in a kettle, then poured into jars, and a lid was placed on the jar. No processing was done. With this method there was often spoilage, because bacteria, yeasts, and molds that contaminated the food when the jars were filled were not killed by further processing. The growth of these microorganisms, in addition to spoiling the food, often caused lids that did seal to later come unsealed. This method resulted in a very real danger of botulism."

Using Paraffin

The USDA says:

"Because of possible mold contamination, paraffin or wax seals are no longer recommended for. any sweet spread, including jellies."

 The University of Minnesota's Extension says:

"Note. Jelly jars and paraffin are no longer recommended. An incomplete seal with paraffin and the absence of a heat treatment may result in mold growth and toxin production in the jelly. Persons continuing to use the paraffin / no water bath method should be aware of the potential health risk."

 

References

This is just a small sampling of the many authorities who concur that the only safe home canning methods are the water bath canner (for jams and acidic fruits and vegetables) and the pressure canner (for low acid fruits and vegetables, meats, and dairy).  Click on the links to see their articles.


Read more at http://www.pickyourown.org/cannersnotrecommended.htm#c6laTiOicTUTQ5Wh.99