canning question

[cabo]

I can tuna and spring Chinook and have done quite a bit of it. I canned a canner full of 1/2 pints filled with fresh Springer. Out of the 24 jars, five broke (the bottoms seperated from the rest of the jar). Weird thing was that four of the jars were on the bottom rack. I put spacing plates between each level of jars and did not do anything different than I have done dozens of times in the past. To loose five jars of freshly canned Spring Chinook is frustrating to say the least.

Do any of you have ideas about what i might have done wrong??????

The jars were new Kerr jars, never used before. Also, the amount of water, pressure, etc..etc...was identical to all other canning I have done.

Any help would be appreciatad.

Thanks,

[iwanttofish]

Maybe a bad batch of jars?

[Tuna Chaser]

Did you have a spacer at the bottom of your canner between the bottom and the jars? If you did, then I would have to think you might have gotten a bad case of jars as well. I never used Kerr jars. Always used Ball. Probably had 4 or 5 broken jars out of hundreds of batches.

[1991 Arima]

That happened to me too and I think it was putting jars in when cooker was too hot, since then I have put jars in while cooker is ramming up, no more broken jars since.

[firemouse5]

I had the same issues once. I determined it was from putting too cold of jars into water that was already warm or hot. Ramping up the pressure too fast can do it too. I put same temp jars and water in the canner and slowly raise the temp with the pressure weight off until I feel certain the jars have had time to increase temperature with the water.

[DogZilla15]

I pre-heat the jars before filling and don't crank up the heat (a little at a time) till the lid is on.

The only problem I've had is with the little half pints.

[firemouse5]

They very same thing can happen in reverse also. Never remove the pressure weight or any type of pressure. The canner must cool and reduce on its own. Implosion versus explosion on the jars. The bottom edges of the jars are the weakest area of the jar. That is why the bottoms usually break out first. Heating too fast causes an implosion. Cooling too fast causes the explosion. You can hear the implosion from the same room... But you can hear the explosion from outside.....

I know both of these from experience... trust me!

It is fascinating to me how much science is involved in canning.

[fishin' is livin']

Originally Posted by firemouse5

They very same thing can happen in reverse also. Never remove the pressure weight or any type of pressure. The canner must cool and reduce on its own. Implosion versus explosion on the jars. The bottom edges of the jars are the weakest area of the jar. That is why the bottoms usually break out first. Heating too fast causes an implosion. Cooling too fast causes the explosion. You can hear the implosion from the same room... But you can hear the explosion from outside.....

I know both of these from experience... trust me!

It is fascinating to me how much science is involved in canning.

HHHMMM, sounds like when I loaned the canner to my dad!!

[Tinman]

My guess is you depressurized too quickly after turning the heat off. Manually venting steam, or cracking the lid open, when there is still pressure inside causes rapid cooling of the jars, which may crack.

[Fshklr]

over filling your jars....the product inside swells in the canning process...then shrinks in the cooling process.

I've luckily only broke 4-5 in the last 8yrs or so....each time the jar was overfilled.

[Moosemeat]

So, to sum up, thirty years iof canning has led me to this process, which is pretty much what everybody else has said:
1. Never overfill jars- leave plenty of headspace.
2. Put cold jars ionto a cold canner (I think this is the most important thing)
3. Always use the spacer plate below your bottom layer of jars.
4. Never vent steam or pressure. Besides breaking your jars, this is dangerous! Let the canner cool until the pressure is zero and the little indicator drops back into the lid.
5. No matter what, you will break one once in a while!

[Boatdog]

Also, don't overtighten the rings. This can blow out the bottom of the jars too.

[Threemuch]

All good advice here. Go slow in raising and lowering temp, and don't screw the lids on too tight, leave 3/4 to 1" head space and I don't think you can break a jar.

[cabo]

Thank you to you all......all excellent advice. It is so awesome to get this kind of response from the "community"........thank you again!!!!!

Still not sure what it was, but four jars on the bottom rack would lead me to believe it has to be something to do with heat. I put it on a gas range, so it does heat up quickly.......will watch it next time.

Funny thing is, it has not happened like this in the past......but I havd gone to Pints (not half pints) for my tuna.

You people rock!!!!!!

GS