Pasteurization

From SackWiki

What is Pasteurization?

There are two inventors we all remember from our grade school lessons -- Eli Whitney, who made the cotton gin, and Louis Pasteur, who discovered how to make milk safer. We all know that milk is pasteurized, but what most of us don't know is that there are three basic levels of pasteurization, and which one you used greatly affects the cheesemaking process.

• Traditional pasteurization can be LTLT (Low Temperature Long Time), where the milk is brought to 145F for 30 min or HTST (High Temperature Short Time), where the milk is brought to 162F for 15 sec.

• Ultra Pasteurization (UP) takes the milk to temperatures from 191-212 F for varying times. Once the temperature rises above 174F, the calcium component of the milk will be damaged to the point that a curd will not set or develop properly, thus rendering the milk essentially unusable for cheese production.

• Ultra High Temperature Sterilization (UHT) takes the milk to 280F for 2 seconds. This allows the milk to last on the shelf, unrefrigerated, for 60 days or more.

The problems with pasteurization

Although it may sound really nice to hear that your milk is "ultra" pasteurized, and that all the "bad" stuff has been removed, pasteurization (especially UP) diminishes the nutrient value of milk. Calcium and other minerals become unavailable, including phosphatase, which is essential for the absorption of calcium. Another problem is that fresh milk naturally contains healthy bacteria that inhibit the growth of undesirable and dangerous organisms. Without these friendly bacteria, pasteurized milk is more susceptible to contamination.

Which is best for cheesemaking?

Obviously, the less your milk is processed, the better it will be for making a natural product such as cheese. UHT milk is completely useless for making cheese (or anything else, really, considering the damage that has been done to the milk). UP milk is not going to work, either, because the calcium damage prevents proper curd formation. Traditionally pasteurized LTLT or HTST milk are the best options for cheesemaking, because the milk has been modified the least. Raw milk from a cow is ideal, but difficult to obtain, since raw milk sales are illegal in most states.

What is available in the stores?

The real problem with determining what is available in stores is that there is no law requiring UP milk to be labeled as such (though there is such a law for UHT milk). That means that in most cases, you don't really know what you are getting. And since UP milk lasts longer, milk producers like it because it allows their product to have a longer, safer shelf-life, and reduces the urgency to ship their product quickly. I have noticed that almost all organic milks that come in cardboard cartons are clearly labeled as ultra-pasteurized which, to the uninitiated, may sound like something you want. I have also noticed that almost all milk that comes in plastic gallon jugs is ultra-pasteurized, but not labeled as such. If you go to a specialty store, you will hopefully be able to find the rare LTLT or HTST milk, typically produced by local farmers. These producers know what they've got and understand why it's important, so their labels clearly indicate and describe their methods and the benefits they offer. Essentially, while first instinct may be to assume something is not UP unless it says so, it's a better assumption to assume it IS UP unless it says it's not.

So what does this mean to me?

From Day One, I knew to avoid UP milk. It was clearly noted in the cheesemaking books I had. I had seen whipping cream labeled as UP before, and assumed that anything UP would be labeled UP. I began and continued my cheesemaking process and made multiple mozzarellas, some of which worked, and some of which didn't. I made several hard cheeses, all of which were too dry and just didn't seem right. I searched for answers to the problems I was having, but I couldn't find them. I was following the recipes, I was doing it right. It just wasn't working. Then one day I stumbled upon a fantastic comparison of ultra-pasteurized vs regular milk. When I saw these pictures and read the details, I knew instantly that my problem was the milk I had used all along. I researched more and learned that the label does not have to indicate whether the milk was ultra pasteurized, so I had been purposefully trying to avoid the bad stuff, but was using it anyway and didn't even know it. I was elated by the news, because it explained my problems and gave me a solution.

The next step was to find non-UP milk. This turned out to be a much harder task than I thought. I spent two weeks making mozzarella whenever I had the chance, and tried milk from Kroger, Wal*mart, Trauth (bottled in Newport, KY), and Flav-O-Rich (bottled in London, KY). I hoped that local milks might not be UP, but I was wrong. I got the same results as always, and never an improvement. I finally ventured into a Wild Oats store and found two brands of suitable milk, both produced by farmers who were clearly proud of their product. I purchased a half gallon of organic whole milk made by Farmers All Natural Creamery (at twice the cost of regular milk). Besides the typical benefits associated with organic milk the label had two main benefits that sold me -- the milk was vat pasteurized, which means LTLT (yay!), and it was non-homogenized, which means there was still a layer of cream floating on top of the milk. I had read that "cream-line" milk was great for cheese, so I was fascinated and thrilled at the discovery.

What difference did the good stuff make?

A world of difference! There is really no comparison. All the stuff I had made before was not cheese. It was a thickened milky mass, which may have looked a little like cheese, but wasn't even close. I didn't realize how bad the UP stuff was until I saw the results I got with the LTLT milk.

I haven't tried a hard cheese yet, but here's what I saw when I made mozzarella:

• Setting the curd - In my old efforts, I was doubling the rennet (which I thought might be old and weak) to increase the curd set. I was also letting the curd set for 15-20 minutes before getting what I thought was a clean break. With the new milk, I used double rennet again (Oops! Old habits are hard to break) and the milk set in about 5 minutes. Beautifully and firmly, I had some major curd action going on.

• Cutting the curd - In my old efforts, I would slice through the curd with a knife, and it was like slicing through whipped cream -- easy, smooth, and not very effective. With the new milk, the curd was so firm (I really shouldn't have doubled the rennet!) that cutting it was like cutting dough. The glob was so firm that the knife pushed it more than cut it. I managed to get the curd into a few pieces, but they were not cubes by any stretch. I'm certain that if I had used the proper amount of rennet, though, I would've gotten the proper cube formation.

• Resting the curd - In my old efforts, "cutting" the curd would lead to some whey separation between the cubes, but as soon as I attempted to retrieve or move a cube, it would disintegrate into tiny globs. With the new milk, there was a large mass of curd that wasn't going anywhere, and could even be stirred around the pot.

• Draining the curd - In my old efforts, I would use a slotted spoon to carefully scoop out as much of the cheesy bits as possible. This usually took in the neighborhood of 20 or 30 scoops before I would finally get it to the point where I could pour the rest into the colander to try to get as much out as possible. I would then have to press and squeeze the curd in the colander for several minutes to expel as much of the whey as possible. It was arduous, but I had finally figured out a technique that worked. With the new milk, it took me exactly THREE scoops with the spoon, and I had it all. Hardly a spec of curd was left in the whey, and the curd in the colander was firm and stood up. It then only took a few minutes to flip and press the curd mass until most of the whey was gone, and I was left with a great looking lump of curd.

• Heating and stretching the curd - In my old efforts, I quickly learned that the first microwave heating of the curd had to be done carefully, and all whey needed to be expelled after that, or else I might as well not continue, because repeated heatings would cause it all to turn into ricotta otherwise. Then repeated heatings finally led me to a very soft and melty blob of cheese, which I could stretch and pull. With my new milk, the first heating expelled whey, and so did the second. There was no danger of losing this curd -- it was tough and strong. When it came time to knead and stretch it, I realized that this was REALLY stretching. Like taffy, I was able to pull this cheese out to long lengths, fold it back on itself, and stretch it again. I could see the stringiness forming, like you expect in mozzarella.

• Taste while warm - In my old efforts, I have to admit that the fresh, warm, cheese was quite tasty. It was mild and soft, and went down quickly. It was definitely better warm than cold. With the new milk, the warm cheese was tougher. It had a squeak to it (which I later learned is desirable), and while it had great taste and texture, I don't think it was better warm than cold.

• The yield - In my old efforts, my yield varied. Sometimes I would get a baseball-sized ball of cheese, sometimes less or more. With the new milk, I did only a half gallon batch, yet got almost as much yield as I used to get from a whole gallon. I eagerly await seeing how much cheese I get from full batches in the future.

• Storage - In my old efforts, I had tried multiple methods for storing the cheese. If I made tiny cheese balls and put them into water or brine, they would become slimy, the water would become cloudy, and the cheese would eventually dissolve into the water. If I wrapped it in plastic, it would maintain the texture, but the shape would collapse into a flatter oval shape, rather than the sphere I had started with. With the new milk, I was able to store tiny balls of cheese in water for days, with no deterioration of quality or taste. I was able to store larger balls wrapped in plastic, with no change in shape.

• Taste while cold - In my old efforts, the cheese was pretty good after chilling. It definitely changed texture, and was more creamy and pasty, especially after a few days. The texture on the inside and outside didn't match. It was okay, but not something I wanted to snack on. With the new milk, the texture solidified quite a bit (remember, I used too much rennet), and it became nearly identical to brick mozzarella you buy in the store. The texture was consistent throughout the entire cheese, and it tasted great. I could definitely eat it on crackers and snack on it when hungry. I'm sure that if I had used less rennet, I would have a great softer mozzarella.

• Melting quality - In my old efforts, attempting to melt the cheese was fruitless. The surface would become dry and the inside would become creamy. It tasted bad and looked bad. With the new milk, it was a different story entirely. The cheese melted like mozzarella is supposed to. It was stringy, gooey, and SO tasty. Fantastic. I can't wait to make a pizza.

So what now?

Now that I know how to do this the right way, there will be no more hesitation. I'll be making new cheeses soon so that I can get them into my aging fridge, where they'll sit until they provide me with a treat months later. I will have to bite the bullet and pay for the more expensive milk, but it'll be worth it. Stay tuned!