Questionable milk quality

[Guiseppe]

I'm new to this game, so please bear with me on this.

I have only been making cheese for a 3 months and I'm on a steep learning curve.
I currently only have the one reference book to work from; my Christmas present cheesemaking book has not yet arrived (see below).

I live on a small Greek island which from a cheesemaking point of view is something of a mixed blessing.  We have no cows here but many sheep and goats.  The only cows milk available to me is from the supermarket and it is pasteurised and homogenised, the only choice is to take it or leave it.  All our cow's milk comes from mainland Greece and arrives by ferry.  If we have very bad weather we sometimes have no ferrys arriving for 5 or 6 days yet even when that happens the supermarkets never run out of milk.  The conclusion I draw from this is that at any given moment the supermarkets must have nearly a week's supply of cows milk in store and it surely follows that what I buy is at least a week old before it even gets on the shelves.

If that is the case I am wondering what process is used for the pasteurisation.  The milk is certainly not UHT but equally I suspect it may be pasteurised at a higher temperature or for longer than might be normal in order to retain a long shelf life.

I have made about a dozen batches of cheese so far, everything from farmhouse cheddar to stilton but with varying levels of success.  In a nutshell I rarely seem to get a firm set and the set I do get seems to take longer than any of my recipes suggest.  I suspect that the problem is the quality of the milk.  I am adding CaCl as recommended and using liquid vegetarian rennet but the dosing rate for each seems pretty varied depending on the recipe.

Last week I managed to source some raw goat's milk, produced locally and in my hand within a couple of hours from milking time.  I used it to produce farmhouse cheddar using the same recipe as I have used three times before.  I mistakenly added a small dose of CaCl solution because I was reading the recipe I had previously used with the pasteurised cow's milk.
It was something of a revelation because it was the first time I had a really firm set and a proper clean break.
Once again, the conclusion I drew from this is that there is nothing wrong with the batch of rennet or the batch of CaCl I am using, the previous problems must be due to the quality of the cow's milk.

I have had a look at all the recipes I have used so far and the quantity of both CaCl and rennet varies widely between recipes; some recipes use as little as .15Ml per litre and other use as much as .9 Ml per litre.

My question now is this - is there a recognised dosage rate for rennet and CaCl or is it right that it varies between recipes.
Is there an upper limit for how much I could use?  I'm guessing that since CaCl is merely a salt in solution it should not be that critical to the end result since I will be putting several teaspoons of cheesesalt in later anyway.  But what about the rennet?  What would happen if I put twice or three times the dose as given by the recipe - would it actually make any difference?

Sorry if this is blindingly obvious but as previously stated, until Amazon and the Greek postal service manage to get their act together I'm somewhat stranded, both metaphorically and literally.

[Sweet Leaves Farm]

I'm really new at this, but I do know that my recipes do vary in how much rennet they use. I also don't have to use CaCl, because my fresh goat milk is really high in calcium. I suspect that the store bought milk doesn't support the acid development you need for the rennet to work. Can you give us anymore specifics?

[Danbo]

Have you used the same meassuring spoon for CaCl as for rennet? Someone here in the forum mentioned that rennet does not like CaCl unless it is dilluted in the milk.

Just a guess...

I add CaCl while the milk is heated.

Keep up the spirit!

:-) Danbo

[awakephd]

καλημερα! Yes, the type of milk can make a huge difference -- the fact that you experienced such a difference with the raw goat's milk is indicative.

For CaCl, my understanding, based on Gianaclis Caldwell's book, is that the max to be used is 1/4 tsp per gallon of 32 percent solution. More than that can actually have a negative effect.

As for rennet, there are too many variables -- not just single strength vs. double strength, but brand to brand and batch to batch can vary. I'm finding that I can use a lot less than I thought I needed. The "flocculation method" (do a search here for details) is the way to determine how much you really need ... but I have found that I can't get usable results with the flocc method and the P&H milk I usually use. The method did work, however, when I got my hands on some raw milk.

[Guiseppe]

Sorry for the delay in replying; I managed to get hold of 3 litres raw goat's milk and 3 litres raw ewes milk so I thought I would make another cheese with this but using the same CaCl and rennet as before to see if it made a difference.

I stumbled upon a recipe as posted by Stuart Dunstan on this site back in August 2014, a recipe he got from Graham Redhead.  The recipe is titled 'Blue Vein Recipe' and from the pictures looks very much like a ripe Camembert but with blue veining, much like Gambozola - right up my street.
I followed it to the letter figuring that if I deviated from it I would actually learn nothing.
I dissolved my CaCl and my Rennet in rain water that I had put in the fridge to bring it down to 4C (another suggestion I picked up from this site).
I tried the flocculation method to determine when to cut the curds and the time I got was somewhere between 13 and 15 minutes (note to self, test every 30 seconds next time).  The recipe gives a cut time of 70 minutes which I figured was pretty close based on the flocculation time.  I kept looking at it in the meantime and at 35 minutes I had a firmer set than any cheese I had previously made.  I was tempted to cut at that point but resisted the temptation and hung on for the full 70 minutes as per the recipe.  By that time I had a virtually solid curd mass which was already under 1/4 inch of whey and the whole thing had pulled away from the side of the pot all by itself.  If anything it was set too firm.
I'm guessing (I seem to be doing quite a lot of that recently) that the original recipe is using pasteurised milk which is why it calls for additional CaCl to be added.  Next time I make this using raw ewes milk or raw goat milk I will omit it, I suspect it will not need it.

6 litres plus a dash of cream gave enough curds to fill four circular moulds 4 inches diameter and 4 inches high (10cm x 10cm).  They've been in the moulds 6 hours now and have dropped by about 1/3rd.  They look like they will end up about two inches deep.  They're now resting on boards waiting to be salted tomorrow.

What I have learned from this is that my store bought cow's milk is incredibly variable in quality whereas the raw goat and ewe's milk which I source locally is good, if anything I can probably get away with using less rennet than the recipe gives and the CaCl can probably be dispensed with entirely. 
I may even do a repeat of this recipe later this week using half the rennet and no CaCl to see what difference it makes.  I appreciate that this will mean I have 8 soft blue cheeses on the go but that is a cross I'm willing to bear - somebody has to do it, I'm selfless to a fault.

Sweet Leaves Farm - Unfortunately I do not have access to a ph meter yet so I am unable to comment on the acidity or otherwise.  Fortunately my birthday is on the horizon and I'm sure if I point these things out to my better half she will take the hint.  I have enough aftershave and socks to open my own store so hopefully she will do the right thing.

Danbo - yes, I did use the same spoon for the CaCl and the rennet but I am virtually obsessive about cleanliness when making cheese and the dirty spoon is rinsed under the tap before being plunged into a bleach solution and again rinsed under a running tap which feeds rainwater.  There is absolutely no chance of cross-contamination.

Awakephd - Unfortunately I am yet to work out how to get my keyboard to type in Greek so in the meantime, 'Good Day' to you too.
You may remember replying to my introduction a couple of weeks ago and you recommended Giannis Caldwell's book to me - well that is the very book I am waiting to arrive.  It should have got here by Christmas but Amazon got it wrong and it's not going to be here for another couple of weeks.

I think the answer is to ignore the cows milk and stick with the local raw goat and ewe milk.  The only reason for using the cow's milk is price - goat and ewe milk is $14.40 or £10.00 a gallon, cow's milk is less than half that price.
Thank you all for your comments, It's good to know there's help out there.  I may even post some pictures of my latest offering once it's ready to eat.

[Stinky]

I use the same measuring spoon for CaCl and rennet all the time, hasn't killed me yet.