Re(2): Tomato sauce question, sort of OT.

> 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

That's a good point, yus.

Remember, the way it seals is that the food inside is at

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

That cannot happen if there are

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