Thank you Dave!! So just a follow up question... If the issue is ensuring whether my sauce has an appropriate pH level (4.5 or below, right?) then could I open a jar and test the acidity levels using strips or an electronic pH tester? (It would be my first time doing that.) And yes, all my herbs were fresh (parsley, basil, oregano etc).

Oh and one more important detail I forgot to mention -- I actually DID put citric acid (1 tsp per quart) in all the jars when I first pressure canned them all, then I had an issue where some of the lids did not seal correctly (I suspect I wasn't waiting long enough during the steam pipe cool down process to remove the canner lid). I had also noticed before that the sauce tasted a bit intense/rich, so I opened up the unsealed jars, put them back into the big stock pot, used the opportunity to improve taste by adding a bunch of store-bought strained tomatoes, brought the sauce back to boil and simmer, and reprocessed the jars with new lids, this time without any additional acidification. So the strained tomatoes were essentially the only "new" product after my first go-round with acidification. So does that help my case? Should I still plan to test the pH level to be safe? Thanks again!

" If the issue is ensuring whether my sauce has an appropriate pH level
(4.5 or below, right?) then could I open a jar and test the acidity
levels using strips or an electronic pH tester?"

You could but it isn't recommended simply because of the high level of inaccuracy associated with litmus paper and the need for experience with correctly using pH meters and calibrating them.

Plus while something may test safe initially pH isn't long-term stable. It rises during shelf storage and can rise into the unsafe range.

And pH isn't the only issue. So is density as it determines the amount of processing time needed to insure full heat penetration so no cold pockets remain.

Adding the additional tomatoes might have helped with the pH issue but would have also changed the density so the safety concerns remain. Adding the acid to begin with helps but that amount covers the tomatoes only, not the other ingredients you added - especially the fresh herbs and carrots. Dried herbs are always allowed as they make no pH change but fresh herbs makes a substantial change.

Bottom line is this is why we are taught that we can't make up our own canning recipes. There are simply too many unknown variables that we can't account or control for. True some would make only a marginal change, others could prove really dangerous. So when we make those changes we are choosing to give up the guaranteed safety of the food and accept additional risks. Some are comfortable doing that, others are not. We each choose our own level of acceptable risk.

I personally don't care for much risk so I wouldn't be comfortable with your sauce as is. Too many changes. But that is just my personal opinion. If it was mine, I would dump it all back into the pot bring it back to boiling, rejar with new lids and process it for 45 min. Adding more citric acid is also an option. Neither approach will harm the sauce. If it is too acidic after you open the jars you can always just add a bit of sugar.

JMO

Dave

Thank you again Dave! I appreciate all of your info, it is super useful!!

So it sounds like the safest method is to open the jars, dump them all back into the pot and start over, this time adding more citric acid. Is there a reason you said I should process them for 45 minutes as opposed to just 25 mins as the recipe suggests? Perhaps because of my added carrots and fresh herbs- the extra time will ensure safety? Also another question-- I canned all these jars Friday night, and I won't be able to start over until tomorrow (Monday) so the sealed jars will have been sitting out for about 48-72 hours. Does this pose a problem?

Yeah that makes them well past the recommended re-processing time limit of 24 hours so the choice to do it or not is yours. I would but that is just me. Strict adherence to the guidelines and what we are taught would have you throwing them away unopened based on the assumption that they may now be contaminated. Personally I won't go that far if salvage is safely possible. JMO

Yes the additional processing time is to cover the added ingredients. It won't hurt a sauce in any way yet adds a good safety margin. Again, JMO but hopefully you have gained some good lessons out of the experience for future use. Stick to instructions and make elective changes AFTER you open the jars. ;-).

Dave

Wow thanks again Dave, this is super useful info, you are a wealth of knowledge and very generous to share your time and input on this forum!

So just thought I'd share an update... I couldn't resist the urge to get science-y, so I went ahead and bought an electronic pH tester (Luckystone brand, found it on Amazon same day delivery), calibrated it with 4 and 7 pH buffer solution, then tested it on about 5 different jars. Here's what I found: the first batch (in which I had added 1 tbsp per quart citric acid) had 4.2 pH. The second batch (in which I added store bought tomato sauce but no additional citric acid) had a range of 4.1-4.3 pH, though one jar rose occasionally to 4.4 as I moved the tester around in the sauce.

So my first question is, what is the "safe" level of pH that I would hypothetically be looking for? I saw a report from the WHO that says "less than 4.6" (http://www.who.int/mediacentre/factsheets/fs270/en/)... But browsing this forum, I found another comment post (from you actually- you are quite the prolific commenter!) where you say anything 4.2 or below is acceptable (http://forums.gardenweb.com/discussions/1947104/using-a-ph-meter-and-lowest-ph-to-kill-botulism). Could you clarify? If the cutoff IS 4.2, then it would seem that I'd either need to throw away all the sauce, or dump it back into the pot and process all over again for 45 min. And I understand that even if we went with the WHO standard of 4.6, there are still several risk factors such as 1) this was my first time using a pH tester and it's not a $1000 top of the line commercial tester, 2) pH levels can change over time, as you shared, and 3) density of the sauce may also be an issue.

Another thing I noticed when I was looking at the jars... Most of the jars have strange looking pockets of liquid toward the middle/bottom of the jar- when I turned the jars to the side, I noticed the bottom half of the jar (which had these pockets) had a noticeably denser consistency. I took a few jars and gently turned them from side to side, which mixed the sauce up a bit, then those pockets disappeared and the sauce looked much more uniform. Are these pockets an area of concern, or something that can typically happen when pressure canning pasta sauce? I wanted to bring it up because you had mentioned density levels can be an issue. In one of the jars, I maneuvered the pH tester into the dense area, and the pH rose from 4.3 to 4.4.

Again many thanks!

Jon

4.6 is the top ceiling, the line in the sand you cannot step over. So you always want to be below it.

4.2 insures a margin of safety and room for the pH to rise, as it gradually does during storage, without breaching that ceiling. The more acidic the longer the storage time.

Yes, you do get pockets of different density and yes that can be a concern. Some due to normal separation, some due to the contents. But since heat doesn't penetrate those dense pockets as quickly or effectively the processing time in PC in crucial. That concern is doubled when oil is included since the oil settles into the pockets and insulates any bacteria they may contain.

Those pockets of density have already been tested and found safe IF one sticks to the recipe instructions. Indeed ALL the scientific testing has already been done for us in the NCHFP/USDA labs. Most of us aren't qualified or even inclined to have to repeat it at home. They have even taken it a step further and found a balance between safety and quality of the end product. So all we have to do for guaranteed safe foods is follow the instructions.

Problems only arise when we choose to deviate from those instructions. That's when risk increases and we either have to accept that risk or find a way to compensate for it while not sacrificing all the quality. I have suggested a method of compensating for that increased risk you incurred. But the longer you put off either doing it or pitching the sauce that risk is increasing exponentially. Per the guidelines that sauce should have all been pitched by now, unopened, jars and all. So if you are going to try to salvage it its time to put the science aside and get out the pot. ;-)

Dave

Thanks Dave, so I ended up re-processing most of them as you suggested and freezing the rest. Good to go. And lesson learned for next time around- I'll be sure to follow the recipe!