I got some canning material from the 40’s and thought I would share what was said about canning lids and caps. The material has been updated when necessary. Check out the 1947 Blue Book that was only 35 cents!
1. Are caps affected by vinegar or any acid foods?
The cap is not affected by any acid foods or vinegar. The caps used to be a gold lacquer on the inside and now there is a white poly material. Yes, it is subject to releasing PBA when heated but a very minimal amount that is less than found in store canned goods.
2. Is it possible to reuse caps?
No. The cap’s seal is broken to open the jar. The composition is broken so it can not be reused. (I use some of them for leftovers in the refrigerator but do not can again with them. I always mark them with an X).
3. Can one brand of cap be used on any jar the same size?
Yes, caps are interchangeable for jars in the U.S.
4. Should the screw lids be tightened before processing the jars?
Yes. The lid holds the cap in place till the cap seals through the heating process.
5. Should the screws be tightened if loosened during the canning process?
No. It is best to remove the screws as they are no longer needed after canning. They should be removed when the jar is cooled and sealed or 24 hours after canning. Use the screw lids over and over again. If left on, juices that are on the threads of the screw band will cause the bands to stick to the jars or sometimes they will rust on and make opening the jar difficult.
6. Is it necessary to sterilize jars and lids before processing with hot water bath?
Yes Jars should be cleaned and sterilized due to the amount of bacteria evident today.
7. How can lids be unstuck if stuck together?
Lids placed in hot water will unstuck.
8. Does lid need to be dry?
No after cleaning lid can be wet.
9. Are lids purchased one year viable the next year.
Yes, if kept in cool dry area.