Can't recall which for sure but wife says it was either the 1976 or the 1984 revised guidelines. She is the one that took the jellies & jams courses while I took the low-acid courses. Either way it has been many years back. ;)

Reasons: improper seals, molds and bacterial problems, air trapped in jars, fermentation due to yeasts, etc.

Dave

PS: general consensus here is that books that old should not be used for canning recipes/guidelines.

The 1988 USDA handbook eliminated all methods except for boiling water bath for high-acid products.

It's interesting, though. My 1948 Kerr Home Canning Book already mentions BWB for "Amber Jam", which is an orange, lemon and grapefruit marmalade.

Mainly it's a quality and shelf-life issue, since the risks with sweet high-acid preserves are minimal. Dave has already mentioned the problems.

Studies have shown a higher rate of seal failures with inversion. In big batches this can become a problem. Frankly, if I weren't going to water bath I'd just sterilize the jars and hot seal the contents, which was common when I was growing up. I think the vacuum would be at least as strong as with an inverted jar. I'm not recommending this, just saying I don't see much benefit in inverting.

Carol

It was changed in the 1970's as far as I remember. I think 1974.
The pectin boxes had the inversion method and may still have in some packages. That is nothing more than the unsafe method of "open kettle". Not a thing is done to get a true vacuum seal or to kill and bacteria. You seal it all up in the jars and it sits there and grows.

Your replies have come from the most respected people here and everything they say is true, factual, and up to date. Be safe, do it the approved way.

Jelly = 220°
Water = 212°

I followed waterbath the last time and the jars sealed as soon as they hit the water.

and the jars sealed as soon as they hit the water.

Sometimes, yes but they then release, burp the air, and reseal during the processing. ;)

Dave

Going to bring this subject up again, as I've run across an issue. 1st- certo pectin instructions in two boxes are conflicting in step #4 for cooked jams. 2nd- there isn't any mention of processing filled jars in water bath. One paper insert says to leave on counter to cool, the other nothing once cooked. My step daughter brought this to my attention, and I told her it is important to process for a minimum 5-10 minutes regardless what the insert says. She being new to canning questioned me....I said I would write Kraft Canada/Certo and ask! Guess whar happens next....4 emails later-they still are not reading/addressing my concerns about the food safety. I referred the National Center for Food Preservation to them. Here I'm trying to teach food safety to new canner and this company just thinks I'm not "pleased" with their recipe.

Kinda hoping krogers and digdirt might have a few words. I'm trying not to make waves, just keeping food safety in mind

The difference in the instructions stems from the fact that Canadian manufacturers are not subject to USDA guidelines as US manufacturers are and it has no similar testing body. So the instructions in the box will vary in some cases either side of the border depending on where it was made. Plus many Canadians of European descent learned to can jams and jellies using just the inversion method (no processing) so that is what they expect to read in the instructions and may even insist on it.

Since the only real threat with acidic jams and jellies made with the high acid fruits is molds developing from the air left trapped in the jars they find that acceptable and don't worry about it. They fail to understand that some fruits are NOT high acid or that their shelf storage life is substantially reduced if they don't process.

Many will go so far as to just skim off the mold that grows on top and eat the rest since they don't consider molds dangerous or understand that the mold spores have permeated deep into the jars. That is their choice.

USDA testing has proven the deep growth of molds and the risks of leaving air in the jars so their guidelines don't accept that eating mold is beneficial in any way. So they insist on the BWB processing to force that remaining air out of the jars and prevent mold growth.

All the Jarden/Bernardin publications in Canada tend to closely follow the USDA guidelines but it is a choice they made while other manufacturers choose to ignore them.

It boils down to your choice and which brands you choose to use.

Dave

I'm thinking I'll just use the bernardin pectin from now on. I married into a European family that never canned, and have US family members that I won't can with as they refuse to follow new guidelines. Kinda sad really. Mold, in my opinion isn't good in my food! Unless it's on my blue cheese!

Thanks for your input

" and have US family members that I won't can with as they refuse to follow new guidelines."

Very true for many of us unfortunately.

Dave