I am using jars that were my Grandmas, If she were alive today she would be 111 & I don't know how long she had used them. I always check for any nicks on the rim also do a visual to see if there are any cracks in the body of the jar. I don't worry about the older jars as much as I do the newer ones because they are thicker. The new ones are thinner & to me more fragile. My grandma even used the old glass jar that had coffee in them, a wide mouth lid fits them perfectly, granted she did not use them in a Pressure cooker. but used them to can her fruits, which she used the open kettle method. We still have a few jars with stuff in them stilled sealed tight. The stuff in them maybe mush but I still like to keep a few of them because of my grandma. I wash my jars in the dishwasher as I empty them, may sure they are dry put the flat & ring back on them to keep them clean till next time. That way all I have to do is rinse them out with hot water. Just so you know my Grandma done all her cooking and canning on a wood cookstove. She had one in the house & one outside so she wouldn't heat up the house in the summer.

I don't know that the quality of the new stuff isn't as good. I have seen and used a lot of 50-60-70 year-old jars and they have their share of manufacturing flaws. I admit this is a new one. I'm sure you've figured out the issue with shell beans and peas re swelling and water absorption. We've had several previous threads on the tricky issue of canning these starchy products and the liquid to solids ratio. My husband suggested, just to be on the safe side, to place these jars in a bucket before opening, so that if there is any shattering, the glass won't fly anywhere. Carol

>> It sounds like you are relying upon an out-of-date >> manual that does not correspond to current standards. >> Generally canner manuals are re-printed year after >> year and are seldom updated. No, as mentioned above, I am using the current NCHFP guidelines, NOT the table in the old outdated manual which says I should use 5 lbs. for 10 minutes. >> Are you sure you were looking at the correct section >> of the NCHFP chart? For a weighted-gauge canner >> processing is not recommended above 1000 feet. Actually, I don't think that you are interpreting the chart correctly. As I understand Table 3 it says that over 1000 feet one should use 10 lbs. of pressure for 20 minutes or 15 lbs. for 15 minutes but NOT X lbs. for 10 minutes. http://www.uga.edu/nchfp/how/can_03/tomato_juice.html ------ I believe I'm now starting to understand the scientific explanation for my original question. Normally when you remove a small boiling pot from it's heat source it will stop boiling almost immediately because the temperature of the contents will quickly drop back below 212 degrees and since the atmospheric pressure stays the same it stops boiling quickly. As I am using the higher recommended pressure of 15 lbs, the temperature of the tomato juice is reaching 250 degrees. When I remove my pressure canner from the heat it's temperature drops quickly because it is a relatively small canner which doesn't need much water (1.5 qt) for pressure canning and there is much more air (~7 qt of air) than water. So the pressure canner cools and unlocks and I remove the jars. In the jar there is only a tiny, tiny amount of air which cools quickly and contracts creating the necessary vacuum to seal the lid. But the liquid is still very hot and now the pressure (vacuum) inside the jar is well below atmospheric pressure so the jar continues to boil even though the temperature of the liquid may drop below 212 degrees. - Steve

First of all I am not the on who is spreading scare stories here. and rules every thing to be tossed. Neither do I. But then I don't accept the "do whatever you want, everything's fine" attitude either and I, for one, will take issue with it every time. Second: I said foaming occurs in pressure cooker(when cooking meats ..). But then immediately I added that this should not happen in Canner. So since this post isn't about cooking meats and there is no concerns with foaming it isn't relevant to the issue. Why post it? How does that help? When someone is trying to learn pressure canning and already worried the last thing they need is someone dragging their focus off on an unrelated tangent. Third: I was talking about the principles of weight system and manufacturing tolerances in general. I did not talk about the specifics as how EXACTLY they are machined. It is up to the manufacturer. And there could be variations from one to the next. Vent pipe diameters aren't relevant unless they are plugged...""" is absolutely incorrect. The combination of the hole diameter and the amount of weight determines the amount of pressure held inside the cooker/canner. So if the hole diameter also has a tolerance as well. And any deviation from the nominal can make a difference. Yes that's all well and good info for the mechanical engineer that designs the equipment and oversees its manufacturer. It has no relevance to the person using the canner at home. Milling to tolerances isn't our problem. We aren't going to dig out our calipers and mic the ID and OD of the steam vent and adjust it accordingly. So the info is of no practical use to us and only confuses the issues under discussion. Dave