writes:

"Glenna Rose" wrote in message
news:fc.003d094101d184073b9aca00c67dfb01.1d1842b@ pmug.org...
As long as the pan is deep
enough to cover the jars with an inch or two of water, it should be
fine.
(Jars have to be upright.)

Now this is one thing I have pondered - I've been doing abit of BWB
canning
and I do wonder why the jars have to be upright. Is it something to do
with
the vacuum (or at least for what passes as one, as I understand it) that
forms in the jar and it having to be at the top in the same position as
one
would store the jar ? I can't think of another reason but I'm sure I'll be
enlightened by someone ? ;-)

For a good seal, the lids and the jar edge must be absolutely clean (and
completely smooth). Perhaps if the jars are tipped, as the pressure
builds, it will force particles out into the seal area which will keep it
from sealing. Remember, the way it seals is that the food inside is at
boiling temps with the lid tightly fastened; then as the contents cool, it
creates a vacuum which seals the lid. That cannot happen if there are
even minute particles in the sealing area; the seal will be compromised.
All canning instructions I've read indicate a height of no-fill in the
jar. They also say to wipe the edge of the jar to ensure nothing is on it
before applying the lid.

Make sense?

Glenna

"Glenna Rose" wrote in message
news:fc.003d094101d188f73b9aca00c67dfb01.1d18914@p mug.org...
writes:



Now this is one thing I have pondered - I've been doing abit of BWB
canning
and I do wonder why the jars have to be upright. Is it something to do
with
the vacuum (or at least for what passes as one, as I understand it) that
forms in the jar and it having to be at the top in the same position as
one
would store the jar ? I can't think of another reason but I'm sure I'll
be
enlightened by someone ? ;-)

For a good seal, the lids and the jar edge must be absolutely clean (and
completely smooth). Perhaps if the jars are tipped, as the pressure
builds, it will force particles out into the seal area which will keep it
from sealing.

That's a good point, yus.

Remember, the way it seals is that the food inside is at
boiling temps with the lid tightly fastened; then as the contents cool, it
creates a vacuum which seals the lid.

I'm not sure if it is technically a true vacuum as such but what passes as
one ?

That cannot happen if there are
even minute particles in the sealing area; the seal will be compromised.
All canning instructions I've read indicate a height of no-fill in the
jar. They also say to wipe the edge of the jar to ensure nothing is on it
before applying the lid.

Make sense?

Yus. I suppose the expanding air presses the contents down in the jar if the
jar is upright - which stops any of it getting into the eeny weeny spaces
between the lid and the jar. If it is on it's side then, as you say, it
might be forced into that space.

Might explain why one of my friend's jars which he put in sideways (shallow
pot, you see - but boys will sometimes be boys, he wasn't having any of what
I was telling him probably because at the time I couldn't explain *why* the
jars had to be upright sufficiently to convince him) had stuff tainting the
water from inside the jar. He ate it quick enough anyway so I doubt bugs got
much of a chance to form. He is still alive fwiw. ;-)


Rachael