I'm making 6 gallons of wine from welch's concentrates (6 white grape and peach, 3 white grape, 1 white grape and pear, and I forget what the rest of the mix was exactly, my notes aren't here with me). So, I emailed them to find out about whether the concentrates are standardized to a specific pH, TA, etc, as I thought they probably would be for consistency sake.
So I got a reply, and here it is: "Thank you for contacting Welch's.
Welch's product formulas and manufacturing procedures would include standards for brix and pH for each product made by our company. This ensures consistent flavor and quality.
We appreciate your interest in our products."
They also snail-mailed me two coupons for their juices, so email them if you're planning to make a wine from their concentrates and save some cash. :-)
My batch is bubbling away right now, and will be ready for secondary...whenever I bottle the apple cider that's sitting in my only 6 gallon carboy.