Lemon Cheese Making - No Curds & Whey Separation

[Tetragrammaton]

I tried this recipe as my first cheese recipe but I noticed no separation between curds and whey. I added more lemon juice in case it was not enough, as instructed but even then there was no difference. In the end, I had to throw it all away. What could have gone wrong?

Process Details: I used the thermometer I have for homebrewing, which is (as far as I can tell) well calibrated. I heated the milk to 85 degrees Celsius, poured the lemon juice in, put the lid on and left the pot on the stove with the heat off, so that it keeps the same temperature for as long as possible. Even after adding more lemon juice, I could actually see no difference. MrsKK made a reference about UHT milk, what does that mean exactly? The milk I used was, in fact, pasteurised, but I don't know whether or not it was suitable for cheese.

edit: I checked out the term and found out it's what in our country call "high pasteurisation milk". I did not use that kind of milk, it was just normal pasteurised milk, with a shelf life of 4-5 days.

[MrsKK]

Hmmm.  I hope someone can help you out.  I've never used past/homogenized milk for cheesemaking, so I'm not much help.

[KosherBaker]

Unfortunately I don't have any solutions, just a few remarks and follow up questions. I've used both Lemon Juice and White Vinegar to curdle milk and was able to get it to set using both. However, vinegar is much more consistent than is Lemon Juice.
1. What kind of Lemon Juice did you use? Fresh Squeezed or store bought in a bottle?
2. How much lemon juice did you add per how much milk?
3. Did you stir the milk as you were adding the Lemon Juice and for a few seconds thereafter?

These answers should help the pros around here zero in on the problem. Hopefully.
Also you did not have to throw the whole thing away. Since you did not add any rennet to your milk you could have simply put it back in the fridge and used it for Crepes/Pancakes and such.
Another thought, is perhaps you may consider having 1/4C of white vinegar standing by premeasured so that if the initial inoculation with lemon juice fails, you can try to add the vinegar and see if that works better on the given batch. You should start to see the curds begin to form as soon as you add the acid. Since I'm not sure what country you are in, I'll add that in the US white vinegar has a 5% acidity.
Last thing is a question. What would happen to this recipe if the acid was added to the milk prior to heating it up?

[Tetragrammaton]

Unfortunately I don't have any solutions, just a few remarks and follow up questions. I've used both Lemon Juice and White Vinegar to curdle milk and was able to get it to set using both. However, vinegar is much more consistent than is Lemon Juice.
1. What kind of Lemon Juice did you use? Fresh Squeezed or store bought in a bottle?
2. How much lemon juice did you add per how much milk?
3. Did you stir the milk as you were adding the Lemon Juice and for a few seconds thereafter?

The answers are:
1. Fresh squeezed
2. I added 80 mL of lemonjuice per 1 liter of milk, then added some more, maybe 50 mL or sth
3. I stirred and whisked

I did not see any separation. I live in Greece, so the vinegar here is different, I could check if there is any information on acidity on the bottle. However, how do you think this could be any different to lemon juice?

[Bowl]

Hmm,  try using bottled lemon juice (Jif). I did and I got curd seperation.

Hope this helped 

[Tetragrammaton]

I just tried it again using white vinegar and it separated pretty well, we'll taste the results after it dries. Turns out that it had actually separated a bit the previous time too, the curds, however, were pretty small and few and I thought it had not separated at all. I used a different brand of milk too, this time, so that could have also affected the result.

[DeejayDebi]

You will definatley get different result with different brands of milk. Once you find a good milk make a note of it and use it again.

[MrsKK]

Since you got good curd from this second milk, I would try using the same kind of milk with lemon juice the next time.  If it works, then you'll know it was the milk.  And like Debi says, keep using that brand.

[Tetragrammaton]

That was exactly what I was thinking of doing. I'll probably try it tomorrow with lemon to see the results.

[MrsKK]

Please let us know how it turns out for you.

[Tetragrammaton]

It turned out great! I like lemon much more than vinegar, too. I just a sandwich with this cheese, smoked turkey and cucumber, and it was really outstanding! I think I will be making this cheese quite often. 

[MrsKK]

WooHoo!  It's amazing what one little detail (like milk brand) can do to alter the results, isn't it?

[DeejayDebi]

Yeah that is something that can be frustrating especially for newbies. Also depends on the store sometimes. Store brand milks even in nearby towns can have different milk so it can be a PITA.