Animal, Vegetable, Miracle_ A Year of Food Life - Barbara Kingsolver [72]
It’s no surprise that cultures the world over have found, through centuries of experimentation, countless ways to make it more digestible. Yogurt, kefir, paneer, queso fresco, butter, mascarpone, montasio, parmesan, haloumi, manchego, bondon, emmental, chenna, ricotta, and quark: the forms of altered milk are without number. Taste is probably not the main point. They all keep longer than fresh milk, and their production involves reducing the lactose sugars.
The chemistry is pretty simple. Milk is about 85 percent water; the rest is protein, minerals, butterfat, vitamins and trace elements, and sugars (lactose)—which are dissolved in the water. When the whole caboodle is made more acidic, the protein solids coagulate into a jellylike curd. When gently heated, this gel releases the liquid whey (lactose and water). Traditionally the milk is curdled by means of specific bacteria that eat—guess what?—lactose. These selective bugs munch through the milk, turning the lactose into harmless lactic acid, which causes the curdling.
The sugars that still remain are dissolved in the whey. As this liquid separates and is drained off from the curd, lactose goes with it. Heating, pressing, and aging the curd will get rid of still more whey, making it harder and generally sharper-flavored. As a rule, the harder the cheese, the lower the lactose content. (Anything less than 2 percent lactose is tolerable for just about everybody.) Also, higher fat content means less lactose—butter has none. Conversely, sweet condensed milk is 12 percent lactose. For other products, the amount of lactose removed depends on the bacterial cultures used for fermentation. A good live-culture yogurt contains as many as five different sugar-eating bacteria. A little biochemistry goes a long way, in safely navigating the dairy path.
At our house soft cheeses were the tricky terrain. Factory-made cheeses can vary enormously in lactose content. Fermentation and whey removal take time that mass production doesn’t always allow. Some soft cheeses are not cultured at all, but curdled simply by adding an acid. For whatever reason, store-bought cream cheese proved consistently inedible for us. But I don’t like to give up. If I could monitor the process myself, seeing personally to lactose removal, I wondered if I might get something edible.
Soft cheeses are ridiculously easy to make, it turns out. The hardest part is ordering the cultures (by catalog or online). With these packets of cheesemaking bugs in your freezer and a gallon of good milk, plus a thermometer, colander, and some cheesecloth, soft cheeses are at your command: in a stainless steel pot, warm the milk to 85 degrees, open the culture packet, and stir the contents into the milk. Take the pot off the stove, cover, let it stand overnight. By the next morning it will have gelled into a soft white curd. Spoon this into a cheesecloth-lined colander and let the whey run off. Salt it, spread it on bread, smile. Different bacterial cultures make different cheeses. The bugs stay up all night doing the work, not you. You just sleep. Is that not cool?
Our chevre and fromagina were so tasty, and digestible, we were inspired to try hard cheeses. These are more work, but it’s basically the same process. Most recipes call for both a bacterial culture and rennet (a natural enzyme), which together cause the milk to set up into a very firm curd in just minutes, rather than overnight. For mozzarella, this curd is kneaded like dough, heated until almost untouchably hot, then stretched like taffy, which is a lot of fun. The whole process—from cold milk to a beautiful braided, impress-your-guests mozzarella on the plate—takes less than an hour. For hard cheeses like cheddar, the firm curd is sliced into little cubes, stirred and heated gently, then pressed into a round wheel and, ideally, aged for weeks or months. We have to hide our cheeses from ourselves to keep them around this long. Over time, we’ve converted a number of our friends to the coven of cheesemaking.
At Ricki’s workshop we really did make six impossible things,