Milk not acidifying??

[scubagirlwonder]

Hello all!
It's been a while since I posted, and am in need of some help! I am currently working on a Stilton-style blue (from Pav's recipe), which came out deliciously the last time I made it, but am having the oddest problem-my pH is going the wrong way...My initial pH was 6.6-6.7 before heating milk to 86F, then it was 6.7 when I added my cultures, after 60 minutes pH was still 6.7, same at 90 minutes, at two hours pH was 6.8-6.9 (still holding at 86F). Thought maybe it was just super slow acidification and that the pH would start to turn around and head the right direction...but at the 3 hour mark we're at 7.1.

Think my cultures are dead? Any other ideas? Any clue how to salvage this?

Thanks in advance for your suggestions!
p.s. My pH meter has been calibrated and I've never had any issues or bugs with it so I'm guessing it's not the issue....

[linuxboy]

How does it smell? Is it starting to get a buttermilky/yogurty acid nose?

Rinsing probe after each use?

A few possibilities
- Phage contamination
- Dead culture (seems most likely)
- meter error (less likely)
- There is also one more phenomenon people rarely talk about, and that is that lactic starters will at times produce a small amount of ammonia, which raises pH. But not by that much.
- poor stir to incorp bacteria/gradients in milk post incorp

[scubagirlwonder]

LB I was hoping you would be on here!!!
 
~Milk still smells nice-just the smell I've come to associate with making cheese....
~Yep, I'm rinsing my probe after each use and even soaked and recalibrated it just to be sure.
~I think it's got to be my cultures, They're pretty old and was hoping I could squeeze one last make out of them before tossing them.....bummer.

Thanks for the input! (I think I just needed confirmation of what I already suspected...)

[linuxboy]

Seems like it's started to grow something else if the pH is increasing.

Cultures usually last for a long time... maybe test yours to see? Take a pint or quart jar of milk, add in a bit of powder, and culture like yogurt (but at the appropriate temp) to see if it sets in a day? If it sets like buttermilk, you can use that as starter. Might just need to use more than usual.

[scubagirlwonder]

Think I should dump this milk, then?

[linuxboy]

Maybe salvage into a direct acidified mozz or panir or halloumi?

[scubagirlwonder]

Ok cheese Yoda, guide me!
What would I need to do to turn this into a Mozz?

[linuxboy]

add vinegar to 5.6 or citric to 5.7 raise temp to 92,

add rennet. wait 30-45 mins, then cut, heal stir, and bring the curd mass together and spin

[scubagirlwonder]

Cool! Here we go....