[1vertical]

An interesting read that suggests that the Clostridium botulinum spores  are perhaps
not easily eliminated...and after reading the resulting intoxication symptoms
from exposure to this bacteria, I for one will choose to error on the side of
safety. This is NOT something to play around with IMO.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC202677/

The meat of that article to quote, "C. botulinum spores were consistently
 found to germinate, grow, and produce toxin below pH 4.6. "

IMO, EXTREME caution is warranted when you play with this life force.

[abraxas]

An interesting read that suggests that the Clostridium botulinum spores  are perhaps
not easily eliminated...

If clostridium botulinum spores were a concern in this case, I would assume it would also be a big concern with homebrewed beer.

[denny]

An interesting read that suggests that the Clostridium botulinum spores  are perhaps
not easily eliminated...

If clostridium botulinum spores were a concern in this case, I would assume it would also be a big concern with homebrewed beer.

I believe that the pH of finished beer is too low for it to be a problem.  Not so with canned wort.

[blatz]

this is intriguing me.

a noob question popped into my head:  do you have to chill the starter wort before putting them in the mason jars and pressure canning?  While I realize the jars can handle boiling temps, would the jars be able to handle the shock of putting near boiling wort in them?

Sorry - just trying to think this through.  The thought of being able to just sanitize a flask and put in wort at any time, esp on a work night is enticing.

[Hokerer]

do you have to chill the starter wort before putting them in the mason jars and pressure canning?  While I realize the jars can handle boiling temps, would the jars be able to handle the shock of putting near boiling wort in them?

If you read the instructions closely on the step-by-step of pressure canning, most recommend that you put your empty jars in room temp water and bring that to a boil and then remove them and fill them with your hot stuff.  I suppose that's their way of avoiding the shock.  That said, though, I've never done that as it seems too many extra steps and I've never had problems with thermal shock from mash temp wort.

[MDixon]

Do not chill and no reason to boil.

4.6 is the magic number and while it has been many moons since I attended, the Acidified Foods Certification Class beats that into you so much you will never forget.

[blatz]

Do not chill and no reason to boil.

4.6 is the magic number and while it has been many moons since I attended, the Acidified Foods Certification Class beats that into you so much you will never forget.

no reason to boil b/c it will boil when you can it?  or because you plan on boiling it when you go to make a starter?

I'm confused - I thought if you canned it, you could just open up your mason jar and dump it into a sanitized flask and you're good to go.

[Kaiser]

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC202677/

The meat of that article to quote, "C. botulinum spores were consistently
 found to germinate, grow, and produce toxin below pH 4.6. "

Most interesting. This is from the late 80s yet sub pH 4.6 foods are still considered safe with simple canning. But yes, I don't think I should mess with this w/o having the proper knowledge and background.

Kai

[dbeechum]

no reason to boil b/c it will boil when you can it?  or because you plan on boiling it when you go to make a starter?

When you pull the can from the canner it will still be boiling inside, so absolute no worries about it.

[MDixon]

Also you'll never stop getting break material. I tried several permutations and always got hot break in the jars so finally figured why bother with the boil and so after I sparge, I can the wort. One thing to do is to plan your runoff so the gravity is what you desire for your starters.

[brewboy]

When you pull the can from the canner it will still be boiling inside, so absolute no worries about it.

If it's still boiling when you open or pull it from the canner, then you're not letting things cool long enough.

[MDixon]

I disagree. I've left it until the pressure equates and still had some bubbles rising as if boiling was occurring. I've never had an issue either and have been pressure canning wort for a long time.

[Hokerer]

I also disagree.  I always let it cool down completely on it's own until the little pop-up thingy drops back down (No cheating by removing the weight early).  Even then, when I take the jars out, the liquid inside them continues to bubble and boil for another 10-15 minutes.

[tubercle]

I also disagree.  I always let it cool down completely on it's own until the little pop-up thingy drops back down (No cheating by removing the weight early).  Even then, when I take the jars out, the liquid inside them continues to bubble and boil for another 10-15 minutes.

 That's because when the vessel pressure equalizes you are just getting down to the boiling point of water under the pressure of 1 atmosphere.

  Don't remove the weight early. The liquid in the jars will be way above the boiling point of 1 atmosphere and the liquid will be basically super-heated and the jar lids won't be able to let pressure escape fast enough and the jars may explode.

 If for some reason you can't wait for the pressure to equalize by ambient cooling, run water over the outside of the cooker.

 Just don't remove the weight or screw around with it with a wooden spoon, no matter how fun it might be

[1vertical]

I also disagree.  I always let it cool down completely on it's own until the little pop-up thingy drops back down (No cheating by removing the weight early).  Even then, when I take the jars out, the liquid inside them continues to bubble and boil for another 10-15 minutes.

 That's because when the vessel pressure equalizes you are just getting down to the boiling point of water under the pressure of 1 atmosphere.

  Don't remove the weight early. The liquid in the jars will be way above the boiling point of 1 atmosphere and the liquid will be basically super-heated and the jar lids won't be able to let pressure escape fast enough and the jars may explode.

 If for some reason you can't wait for the pressure to equalize by ambient cooling, run water over the outside of the cooker.

 Just don't remove the weight or screw around with it with a wooden spoon, no matter how fun it might be

OMG man you are spot on!!  I have picked up jars out of properly cooled canners by the ring and found the bottom of the jar detached and sitting on the bottom of the canner....like are you wanting hot scalding liquid to get out of it's container???
The difference in pressure is how you achieve steralization.