I work at a factory that produces calcium chloride and magnesium chloride. I learned from AI that calcium chloride and magnesium chloride can be used in cheese production, but I would like to consult a more professional source. Do large-scale manufacturers add calcium chloride or magnesium chloride as protein coagulants during cheese production?
If they are using pasteurised milk, then yes. Basically, calcium phosphate (the calcium source in milk) is less soluble in water the higher the temperature (similar to calcium carbonate, chalk, and calcium sulphate, gypsum). If you live in a place with hard water, you will see "scale" on you bathroom fixtures and kettle, etc as the chalk and gypsum come out of solution when you raise the temperature.
Milk has a huge amount of calcium in it, but it's bound up in the bundles of protein. Only a small amount of calcium is actually dissolved in the milk at any given time. Rennet works by modifying the casein protein to allow it to bind together using calcium as a kind of glue.
So why add calcium chloride? The answer is because it is more soluble as the temperature goes up (like sugar or table salt, sodium chloride). It also has a fairly high solubility over all so it's very easy to dissolve in the milk. That's the only reason.
Calcium chloride is also very, very, very cheap. It's a naturally occuring salt in sea water and is processed out in many sea salt making processes. So it's easy to get, basically free and dissolves easily.
It has a downside in that it has a kind of bitter taste, but as long as you are careful about how much you add, it's below the level that humans can taste.
If you use raw milk instead of pasteurised milk, usually you don't have to add any. The milk has never been heated and so there is normally plenty of dissolved calcium. Some manufacturers might still add a little bit just as insurance. It's still possible for milk to be deficient in dissolved calcium and if you are make 200 lbs of cheese you don't want to have to throw it out ;-)
I can't really think of a good reason to use magnesium chloride.
Thank you very much for your response. You are truly very professional.
Yes of course since most cheese plants pasteurize milk you gotta add calcium or your curds gonna get destroyed in the vat
Thank you for your answer — I feel much closer to the truth now, haha.
Just to add my two cents: not all large facilities do! We pasteurize our milk on site and don't add any form of calcium. While the others have called out certain advantages, I also don't believe any of the sites affiliated with my manufacturer do so. That could come down to preference or it could be make, but for the size and scale we operate at I would assume that any yield advantage would be captured so likely has to do with performance and flavor.
That said - no additional calcium!
Thank you all for the discussion—I learned a lot.
To add my one cent, it also depends on the origin of the milk and how milk is pasteurized, if it is at high temperature, the calcium lost will be huge and you will have to add Calcium to have coagulation, if its at low temperature the loss will be substantially less and if the milk is from a breed that produces milk with lots of calcium you might not need to add it.
Thank you all for the discussion—I learned a lot.
We do HTST pasteurization at the sites I've visited, and the herds represented are the Midwest and Northwest if that helps add any context to my response. Commercial herds in my area are almost entirely Holstein, but not sure for the other sites. I'm only speaking for the very large scale we operate at. Not sure depending on the smaller scale industrial sites, and definitely not sure on the artisanal scale!
In USA, my information is that the pasteurization temps for HTST milk are creeping UP as more and more pressure occurs in the USA grocery store space for longer milk shelf life. UHT MILK (which won’t make cheese) but which is labeled as “Organic” but kept on refrigerated grocer shelves next to “real” HTST milk is really gaining in popularity, even at 2-3 x the price of “regular” ie non-organic) milk. (I know a dairy scientist at our local land grant University). Concomitantly, I have noticed that Ca Cl2 addition is becoming more and more crucial if one desires any meaningful curd yield when using bulk process (still not UHT) (non-organic) grocery store milk. Translation: The U.S. dairy industry doesn’t give a hoot about hobby cheesemakers. Conclusion, one day in USA, it will no longer be possible to make hard cheeses from ordinary grocery store milk. Because the market will have forced it to morph to UHT like it has in other countries. I was in Portugal recently and all I could find was UHT milk.
Take home: if you are a US hobbyist cheesemaker, seek milk from local dairies where you can get low temp (no more than 63 C) pasteurized milk from to make your hard cheese. Do keep in mind that you can definitely make yogurt, paneer, and maybe quark from high temp >72 C pasteurized grocery store milk or maybe even UHT milk.