GardenBanter.co.uk - View Single Post - Re(2): Tomato sauce question, sort of OT.

22-08-2004, 11:00 PM

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