Curd won't melt

[Veja]

Hello again folks,
I'm trying to make mozzarella again and this time my curds won't melt and get "stretchy".  I have tried both the microwave and the hot water method (water @ 180 degrees).  What would make the curd grainy and not melt or stretch?
Thanks for the help
                                (I really need it!)

[Lennie]

Sounds like you didn't get your pH right.  Did you use citric acid or a thermophilic starter?  I've tried both, it took more acid than my recipe said and it took a LOT longer for my thermophilic culture to bring the pH down.

[Veja]

I used 1 1/2 tsp of citric acid dissolved in cold water.   Should I add more?  How much?  When?  At what stage?
Thanks

[justsocat]

I add 10 g of citric acid to 4.5 l of milk, 50 g to 20 l of milk and get pH 5.3 - 5.4. How much milk do you take for each batch?

[Veja]

Hello Pavel,
I use one gallon of milk (3.8L).   I have used both homogenized and unhomogenized milk with basically the same results. 

[justsocat]

I'm sorry, Veja, but i can't find any data how much tsp of citric acid weights. I bye acid packed by 40 and 10 g. When the quantity of milk i use calls for say 45 g i make 500 ml water solution of 40 and 10 g packs and add 450 ml of it.
As Lennie posted the most possible reason of failure with the mozz is  you didn't get your pH right. Have you had good curd set? Did the curds stick together after draining?

[Veja]

I couldn't find any way to convert grams to teaspoons either.    I think that I will try to increase the amount of citric acid ab about 60%.    And based upon Lennie's post I may also double the amount of rennet.  The rennet that I used was about 18 months old.  I know that it has a 2 year shelf life, but I found a store that has a fresher batch. 

And no, I didn't have a good curd set.  The curds were very delicate and not what I have seen as a "clean break".  After I drained the curds, no, they did not stick together. 

BTW  Do you know what tartaric acid is?  Is it the same as creme of tartar?  Where would I be able to purchase it, at a grocery store?

Thanks for your help.

[DeejayDebi]

I think I used about 1 1/4 teaspoons of citric acid for the microwave method.

[Veja]

I used that too-not good results.  It was still grainy.  I also used double that amount.  Still not good results.

[Lennie]

I used around 2tsp to get my pH right for storebought milk.  There is a fairly narrow window of pH, 5.0-5.2 I think.  So too little or too much an you don't get good results.  I only got really decent results once using the acid method.  I have found that you have to be really careful not to heat the curd too much, it turns to soup and you have to microwave it many times to dry it up.

A good curd set is necessary for this cheese, if the curd is full of whey then you get soup when you heat in a microwave.  Maybe heating in 170F water would work better, that way as the curd melts any whey that comes out doesn't mix with the curd.  I used this method on my last mozzarella and it worked pretty well.  That was traditional mozz but the curds are about the same.

Cream of tartar isn't tartaric acid, its a neutralized salt.  You can buy tartaric acid at any winemaking website, try Midwest Homebrewing.  They probably sell citric as well.

[Lennie]

You might also heat/melt the cheese in the whey, as Debbie just pointed out it will have the same pH as the cheese so it won't throw things off in that respect.

[DeejayDebi]

Lennie you sound like a pro already! Good job!

As Lennie stated heating the curds in the whey seems to work best becuase it don't through off your pH levels. Once the curds shatter and become grainy the only way I know to save them is to keep heating and kneading until they finally melt together. This could take more than a dozen attempts and will make the curds tough but at least you won't waste the milk. I just hate to waste food.

[Veja]

Thanks for the tips guys.  Heating the curd in the reserved whey really makes sense when considering the ph, thanks Debi.
I didn't think that creme of tartar was the same thing as tartaric acid, it couldn't be that easy.  Lennie, thanks for the lead on where to buy it. 

How critical is the heating/melting temp?(170degrees F), or the cooking temp 108 degrees F)?  I may have let the temp go up to as much as 113*F  at that stage.   Is that a fatal error?

Debi,   I tried to salvage the last batch by heating/melting and stretching.  The curd stayed grainy, absolutely would not stretch, and was rubbery.  I hate to throw things away too, but this batch looked unsalvagable.    I will certainly heat the curds in the whey next time.  It seems that my problem is the ph issue.

[DeejayDebi]

Yeah when it gets that bad it's really hard to bring back but drain it in a cloth and squeze out all the whey then nuke and knead the heck out of it. I have  a lot of friends that seem to have this problem every time they try to make cheese alone. The the calls start! 

I get my citric acid at Asian, Korean or Indian food stores. I don't know what they do with it but they always have it.

[Veja]

I tried that too.  Evidentially I did not heat it enough times.  Results bad.
Detroit is a big town, I should be able to find  a store of that sort. 
Thanks