As the head cheese rests in my fridge, I, in the meantime, to forget about all the coagulation in my kitchen, distract myself learning a few things.
First I turn to Harold McGee. In his book, On Food and Cooking, he makes a brief mention of collagen, a protein responsible for connecting tissues, comprising “about a third of all the protein in the animal body” (130). Because it’s mostly concentrated in the skin, tendons, cartilage and bones, it makes sense that Diana Kennedy emphasized the importance of using the skin from the cheeks. According to McGee, the word for collagen, etymologically Greek, means “glue-producing.” When heated in water, it can dissolve into gelatin. In other words, when cooked, it softens. (As it turns out, we and other animals are born with more collagen, and as we age it disappears; hence why veal is more gelatinous and tender.)
While I was picking apart the head, tugging at the jaw and digging my fingers through the eye sockets and other cavities, I discovered all types of different fat compositions. The snout was purely skin and fat.
Collagen, according to Wikipedia, is the most abundant protein found in mammals, making up a quarter to a third of whole-body protein content. Its structure is long and fibrous, and its repeating sequence of amino acids, and its composition of glycine, proline and uncommon derivative amino acids, make it both unusual and a source of interest among microbiologists. But, what’s important to know is that its whole raison d’être is to connect tissues together: fat to skin, muscles to tendons; and, when collagen is hydrolyzed–that is, irreversibly isolated and cleared of any debris–it becomes gelatin. It is the gelatin that will hold all the meat and flavor together in the head cheese. Not incidentally, pig head is a major source of commercial gelatin.
That said, one doesn’t need a head to get gelatin. My grandfather, for example, uses legs or knuckles for his scrapple. You could even throw a few ham hocks into a pot to extract it. When isolated, gelatin is clear and has no taste. It an be used for sweet desserts or savory tapas. It is used in pharmaceuticals, vitamins and supplements, and cosmetics. It is also used to produce aspic. Because they share the same source, molecularly, it is similar to animal glue.
How does all this relate to the head cheese? Before I put the whole mess into the fridge, I wanted to see what the top (or, later, the bottom) looked like.
While handling it, I noticed that the loaf itself was solid. It jiggled a bit with my manhandling, but even at room temperature, the gelatin took effect, not connecting muscle to tendon, but onions and chipotles to meat and cartilage. The vinegar, an acid that promotes the extraction of gelatin, has imparted its sweet flavors into the meat without making it runny with its liquid.
To sum up, I quote Harold McGee:
Connective tissue has two uses. First, in long-cooked stocks, soups, and stews, it dissolves out of the bones or skin to provide large quantities of gelatin and a substantial body. And second, it can be turned into a delicious dish itself, with either a succulent gelatinous texture or a crisp, crunchy one, depending on the cut and the cooking method. Long moist cooking gives tender veal ears, cheeks and muzzle for tête de veau, or Chinese beef tendon or fatty pork skin. A briefer cooking produces crunchy or chewy cartilaginous pig’s ears, snouts, and tails; and rapid frying gives crisp pork rinds.
— On Food and Cooking, p. 168
…which is a great segue into the properties of the skin. What is it about peeling off a juicy, hot, caramelized strip of chicken skin and dropping it into the mouth that produces elation and almost sexual satisfaction?
As a cook, I find myself discarding skins of various vegetables. But when I toss the potato peelings with a glug of oil, and broadcast onto them some salt, pepper and garlic powder, then roast them until crispy, it’s impossible to keep everyone from nibbling them. Even with some fish, I remove the skin for one reason or another, yet nothing compares to the way Chinook salmon’s skin dissolves on the well-salted tongue. But with meat–that is, mammal and bird meat–it is a specialty, especially during that ephemeral moment right off the fire.
Fergus Henderson begins his newest cookbook, Beyond Nose to Tail, with Pork Scratchings, combining merely three ingredients of pig’s skin, sea salt and duck fat. After salting it in the fridge for no less than five days, then soaking it in cold water for one more day, one rubs the skin with fat and roasts it for about 2 1/2 hours. In the end, the glistening “sheet of golden, crispy joy” (8) is a most simple and invigorating offering of a well-rehearsed orchestra of flavors.
Mammal skin has two layers: outer (epidermis) and inner (dermis). The outer layer is responsible for protection from the elements and the inner layer does the same in a different way. The epidermis is composed of keratinocytes (95%)–a mix of proteins, enzymes, fats and antimicrobial peptides–and a handful of other cell types. There is no blood in the epidermis. Whereas the epidermis exists as a barrier to the body, the dermis exists as a channel between that barrier and the body. It is the dermis that gives us physical sensation and elasticity, sweat, hair glands and, of course, blood vessels. It is in the dermis where all the connective tissues occur.
Coupled with the fat and protein of the epidermis and the collagen of the dermis, it is no wonder the skin should be used in head cheese, and why, when fried, it makes such a succulent, naughty morsel. But how curious that the same substance is fashioned into clothing and armor and boats — artificial barriers from the elements for human beings. When we eat the skin of an animal, we are tugged at by moral apprehension and complete satisfaction. It is the sole and fanciful act of cooking that disintegrates those barriers, that allows both creatures to let their guards down, to withdraw from the elements momentarily, and to permeate each other in a way that no other would allow. Everything simply melts.
My one experience with brain is fuzzy. It was definitely in Los Angeles. It was either in a taco or as a stew. I can’t remember. There was a lot of food consumed that week. Either way, while my experience was forgettable, the stuffy and musty aroma of it cooking is everything but. Sensorily it stands out there with the feelings of plugging out the dark gooey who-knows-what from the not-sure-where and that first taste of the broth, the gelatin and fat oozing down my throat with the aplomb and mmm-hmmms of a royal consort.
Anyway, while researching the composition of the brain, I was shocked to discover that 100 grams of it contains around 2,500mg of cholesterol. According to Calorie Count, 3 ounces of beef brain 878% of the USRDA for cholesterol. Wow. Besides that, it’s about 12% fat and very high in phosphorous and selenium, and has sizable amounts of B12. It is a protein-rich food.
Despite there being this information, and despite there being a whole catalogue of brain recipes, there is still squeamishness in eating it. While looking at head cheese recipes, I found some that directed the cook to discard the brain. This one said that it was impolite. Well, I included it on purpose. I did not think it was impolite. I thought it was respectful. Is it better to throw the brain into the trash, let it decompose with plastic wrappers and the gritty, decaying rubber of putrid tennis shoes? Or is it better to keep it with what its been with its whole life, all the way through the natural cycle of digestion? It is up to the cook. But I found the whole affair rather respectful.