Tomato Stock Problem

If you have been following this blog you will know I do a lot of home canning.  Each year I process somewhere between 1,100 and 1,400 jars of food.  For the most part, I experience few problems but those that I do, tend to have me shaking my head because sometimes I just can't explain why the problem occurred.  I have over 35 years of home canning experience so know what to look for with respect to home canning problems which tend to be few and far between.   I know what kind of problems to expect and what to do to prevent the problems from happening in the first place.  Normally, I can pin point the root to any home canning problems.

I canned my third batch of tomato stock in 500 ml jars.  I normally can this stock in 250 ml jars but I was down to 4 empty jars and simply did not want to buy more jars.  The stock was perfect!  I brought it to a boil then ladled into hot jars and processed in the pressure cooker for 30 minutes at 10 lb pressure with no problems.  Once the pressure came to zero, I removed the jars from the canner for their 24 hour cooling period (pictured).  I immediately noticed one jar (far right) was a bit cloudy but the others were clear with a little tomato pulp on the bottom just the way they should be.

I decided to let it sit for the cooling period to see if the stock would clear.  The following day, it was still cloudy.  I removed the rings from the 4 jars, washed and stored but left the cloudy jar out.  In my mind, I thought if it didn't clear after 36 hours I would toss.  My mantra with home canning is always if in doubt toss it out.  Well, the jar of stock did not clear and despite smelling delicious, I emptied it out.  I have no idea what happened.  It was from the same batch, put into hot prepared jars that had gone through the same dishwasher load and processed in the same canner load.  Jar contamination should not have been a problem given I ran all jars prior to filling through the dishwasher and yet that is the only conclusion I can come up with.  Had the stock itself been contaminated, all the jars would have been cloudy.  I know there was no bacterial growth because the stock had been pressure canned. The contents of jars of food coming out of the pressure canner are still boiling inside the jars.  Adding to the mystery, the cloudy jar of stock sealed fine during the cooling period so that wasn't the problem.  At any rate, the problem remains a mystery.