Vinegar.

the-lada-dude, Nov 14, 9:43pm
those vinegars you can buy in the shop, DYCetcwhat strength are they !
that is :the amount of acetic acid as a % of volume.I know for preserving
different products, you will need different acetic acid strengths, as some preserves are more or less acid naturally. In theory you should use a good calibrated ph tester,but anyway, back to the question !

linette1, Nov 15, 1:36am
DYC vinegar has 4 - 4.2 acidity if that's any help.

pickles7, Nov 15, 6:02am
I make all my own vinegars now. I found the vinegar I was buying, insipid.
After my first lot turning out so well I was hooked into a very rewarding hobby. I use it to like any other vinegar knowing it was made properly. I had a tasting of all my vinegars that I had stashed to mature, there is nothing on the market that compares.
http://makingvinegar.blogspot.co.nz/

the-lada-dude, Nov 15, 6:10pm
thanks,