Cooking for Geeks: Real Science, Great Hacks, and Good Food

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Cooking for Geeks: Real Science, Great Hacks, and Good Food Page 41

by Jeff Potter


  Create a filling by mixing together in a bowl:

  ¼ cup (40g) poblano pepper, roasted and then diced, about 1 pepper (see notes)

  ¼ cup (40g) cheddar cheese or Monterey Jack cheese, cut into small cubes

  ½ teaspoon (3g) salt

  ½ teaspoon (1g) ground black pepper

  Prepare the pork chops for stuffing: using a small paring knife, make a small incision in the side of the pork chop, then push the blade into the center of the pork chop. Create a center cavity, sweeping the blade inside the pork chop, while keeping the "mouth" of the cavity—where you pushed the knife into the meat—as small as possible.

  Stuff about a tablespoon of the filling into each pork chop. Rub the outside of the pork chops with oil and season with a pinch of salt.

  Note

  You’ll have leftover filling. It’s better to make too much than risk not having enough. Save the extra stuffing for scrambled eggs.

  Heat a cast iron pan over medium heat until it is hot (about 400°F / 200°C, the point at which water dropped on the surface sizzles and steams). Place the pork chops in the pan, searing each side until the outside is medium brown, about five to seven minutes per side. Check the internal temperature, cooking until your thermometer registers 145°F / 62.8°C. Then remove the pork chops from the pan and let them rest on a cutting board for five minutes.

  Note

  You can pull the pork chops from the pan before they reach temperature and let the carryover bring them up to 145°F / 62.8°C, but make sure they do get up to this temperature. You should also verify that your thermometer is calibrated correctly and that you properly probe the coldest part of the meat.

  To serve, slice the pork chops in half to reveal the center. Serve on top of rosemary mashed potatoes (see Rosemary Mashed Potatoes in Chapter 4).

  Notes

  How do you roast a poblano pepper? If you have a gas stovetop, you can place the pepper directly on top of the burner, using a pair of tongs to rotate it as the skin burns off (expect the skin to char and turn black; this is what you’re going for). If you don’t have a gas stovetop, place the pepper under a broiler (gas or electric) set to high, rotating it as necessary. Once the skin is burnt on most sides of the pepper, remove from the heat and let it rest on a cutting board until it’s cool enough to handle. Using a cloth or paper towel, wipe off the burnt skin and discard. Dice the pepper (discarding the seeds, ribbing, and top) and place into a bowl.

  Try other fillings, such as a mixture of sage, dried fruits (cranberries, cherries, apricots), and nuts (pecans, walnuts); or pesto sauce.

  Trichinosis and Pork

  145°F / 62.8°C? I thought pork had to be cooked to 165°F / 73.9°C!

  Good question; glad you asked. Trichinosis—a parasitic infection from roundworm—has historically been a concern in pork, but this is no longer the case in the United States. The U.S. Code of Federal Regulations requires commercial processors that cook pork to heat it to 140°F / 60°C—well below the well-done temperature of 165°F / 73.9°C—and hold it at that temperature for at least one minute.

  To be safe (well, safer—see the discussion on food safety in Chapter 4), give yourself at least a 5°F / 2°C error window. When cooking pork chops, leave the temperature probe in after the chop reaches temperature and check that the temperature remains at or above 145°F / 62.8°C for at least one minute. If you see the temperature drop down, transfer the chops back to the pan. The pan itself—even off-heat—should have enough residual heat to keep them at 145°F / 62.8°C.

  If you’re curious about the history of trichinosis, see the USDA’s Parasite Biology and Epidemiology Lab fact sheet at http://www.aphis.usda.gov/vs/trichinae/docs/fact_sheet.htm. A century ago, ~1.4% of pork was infected; in 1996, of 221,123 tested animals in the United States, 0 were infected.

  Salt-Roasted Fish

  Salt can also be used as a "protective outer layer" on food during cooking. By packing foods such as fish, meats, or potatoes in a mound of salt, you ensure that the outer surface of the cooked food doesn’t reach the same surface temperatures as it would if uncovered, leading to a less extreme gradient of doneness (see Temperature gradients in Chapter 4).

  Traditionally, the salt is mixed with egg white or water to make a thick paste that will hold its shape and can be packed around something like a fish.

  Note

  When salt roasting, leave the fish skin on. It’ll prevent the fish from getting too salty.

  You don’t need to bury the fish too deeply. Go for about 1/2″ / 1 cm of salt on all sides—enough to take the brunt of the surface temperature but not so much that the center of the fish takes too long to actually reach temperature.

  Try this with a whole fish, something medium to large (2 to 5 lbs / 1 to 2 kilos), such as a striped bass or rockfish (check http://seafoodwatch.com for suggestions). Rinse the fish thoroughly, and add some herbs (rosemary, bay leaf, etc.) and lemon wedges in the center. Line a baking pan with parchment paper (this’ll make cleanup easier), and add a thin layer of salt. Place the fish on top of the salt, and then pack the rest of the salt around the sides and top of the fish.

  Bake the fish in an oven set to 400–450°F / 200–230°C, using a probe thermometer set to beep when the internal temperature reaches 125°F / 52°C. Remove from oven and let rest 5 to 10 minutes (during which carryover will bring the temp up to 130°F / 54°C). Crack open the layer of salt and serve.

  Notes

  Don’t have a probe thermometer? The Canadian Department of Marine Fisheries recommends measuring the thickest part of the fish and cooking for 10 minutes per inch. (Add ~10 minutes for the 1″ / 2.5 cm of salt around the fish.)

  Try this with other foods, such as pork loin (add spices—black pepper, cinnamon, cayenne pepper—to the salt mixture) or even entire standing rib roasts.

  Sugar can also work as a "packing material," provided that the oven temperature remains sufficiently low. Salt melts at 1474°F / 801°C, well above oven temperature; sugar melts at 367°F / 186°C. Given this, you should be able to do the equivalent of salt roasting with sugar at temperatures below 367°F / 186°C (try around 325°F / 163°C). However, it takes less water to dissolve the same amount of sugar, so moist items such as fruits will end up giving off too much water for this to work. When I tried "sugar roasting" an apple at 340°F / 170°C, the moisture in the apple was enough to allow the sugar to dissolve into a syrup. It was still delicious, though.

  100 grams of salt (left) and 100 grams of sugar (right), each with 30 grams of water.

  Carolyn Jung’s Preserved Lemons

  PHOTO BY JOANNE HOYOUNG-LEE

  Carolyn Jung started as a hard news reporter covering everything from plane crashes to trials. She then transitioned to food, working for the San Jose Mercury News for over a decade as a food writer and editor. With "the whole journalism media industry imploding," she started her own blog at http://www.foodgal.com.

  What’s a day in the life of a food writer like?

  It’s one of the most fun, most creative, and most enjoyable professions there is. Food is this innocuous way to get strangers talking, and it’s a very innocuous way to educate people, and not just about food. It teaches people about culture, about history, about different ethnicities, about different places in the world, about politics, about religion. All of those aspects are what really make it interesting, much more so than people think at the outset.

  Where does this recent fascination that people have for cooking come from?

  A large impetus has been the Food Network, which has made food such a phenomenon. A lot of people who wouldn’t normally cook were attracted to shows like Iron Chef because it was almost like watching a boxing match or a football game. Who doesn’t dream about being the quarterback on their favorite team? Cooking shows have been the same; you imagine yourself in that contestant’s position. "Oh, my God, if I got a box with mushrooms and lemongrass and chicken and avocado, what the heck would I make?"

  Why do you think the Food
Network took off?

  I was watching a documentary on the history of how it all developed. Apparently when it started it was a couple of people sitting at a desk, like regular news shows. As the audience started to grow and funding became available, they got people in a kitchen cooking on sets, but it was very rudimentary. I think what they said really made their number of viewers take off was when they started doing shows where they would go to the nation’s barbeque festival or the crawfish festival in the South, things where they showed food as a participatory event.

  What’s been the most unexpected difference between your experience in the print world and your blog?

  As a newspaper reporter, I was used to writing some very long, involved pieces. On the Web, people don’t have that kind of attention span. You have a shorter window of time to attract a reader online, but you’re also able to build a very loyal audience. If someone likes what you’re doing, they will stay with you.

  Are there any particular blog posts that have had much stronger reactions than you expected?

  I wrote about how to make preserved lemons, and how I got, as my husband calls it, almost obsessed with watching my lemons. It’s the simplest thing ever. All you do is make slashes into fresh lemons, fill the cavities with salt, and then pack these lemons in a sterilized glass jar. You top it with a little bit of fresh lemon juice and put the cap on it. As the days go by, the lemons start breaking down and getting softer, exuding more of their juice, and it brines itself in this mixture of lemon juice and salt. I remember the first time I made this, I would wake up every day and go look at my jar of lemons to see what they looked like. It was almost like a science experiment. The fun part is discovering all the uses there are once you have this jar.

  Preserved Lemons

  All you need are washed and preferably organic lemons (either Eurekas or Meyers), kosher salt, and a glass jar with a tight lid that has been sterilized by running it through the dishwasher.

  Make two cuts (lengthwise) in each lemon so that the quarters created remain attached. Stuff kosher salt into the crevices of the lemons. Then place the salted lemons tightly into the glass jar. If I have one or two leftover lemons, I’ll often squeeze the juice into the jar before closing it. But you don’t have to. This just gives the lemons a little bit of a head start.

  Place the jar on a countertop and then just watch and wait. Over the next few days, more and more juice will exude from the lemons, filling the jar. You can give it a shake now and then—or not—to keep the salt blended well in the liquid. In about three weeks, the lemons will get very soft and the brining liquid thick and cloudy. Once that happens, you can store the jar in the refrigerator. As long as the brine covers the lemons, they’ll keep for about a year refrigerated.

  To use, pick a lemon or part of one out of the jar with a clean fork. Give the lemon a quick rinse. Remove any seeds. Then, use the peel however you like—chopped or sliced in thin slivers. Some people discard the flesh, but others consider that wasteful. I always add some of the chopped flesh in with the rind in whatever I’m making.

  Use preserved lemons in your favorite Moroccan chicken tagine recipes. Or stir it into tuna salad for sandwiches, pasta salad, bean salad, vinaigrettes, marinades for fish or Cornish game hens, or in couscous topped with toasted pine nuts.

  For a fast and easy example of how to use these, try making quinoa in a rice cooker. Use kitchen shears to snip one of the lemon slices up into small pieces and mix in with the quinoa before cooking.

  RECIPE USED BY PERMISSION OF CAROLYN JUNG

  Sugar

  Sugar, like salt, can be used as a preservative, and it works for the same reasons. The sugar changes the osmotic pressure of the environment, leading to cellular plasmolysis and inhibiting the growth of microbial cells. This is why sugary foods such as candies and jams don’t require refrigeration to prevent bacterial spoilage: their water activity is low enough that there’s just not any free water for the bacteria.

  Note

  Sugar’s osmotic properties can be used for more than just preserving food. Researchers in the UK have found that sugar can be used as a dressing for wounds, essentially as cheap bactericidal. They used sugar (sterilized, please), glycol, and hydrogen peroxide (0.15% final concentration) to create a paste with high osmotic pressure and low water activity, creating something that dries out the wound while preventing bacteria from being able to grow. Clearly, whoever said "pouring salt on an open wound" didn’t try sugar!

  Sugar Swizzle Sticks

  This is just plain fun. You can make fancy sugar sticks for sweetening your coffee or tea with very little effort. While probably not something you’d use on a daily basis, it’s a fun project to do with kids.

  In a saucepan, boil until completely dissolved:

  2 cups (430g) sugar

  1 cup (240g) water

  Allow the sugar syrup to cool. While waiting, fetch the following:

  1 narrow drinking glass

  1 small wooden cooking skewer

  Tape, such as masking tape

  Plastic wrap

  Dip the first two or three inches of the skewer into the sugar syrup and then into dry sugar to create seed crystals on the stick.

  Stretch a piece of tape across the top of the drinking glass and poke the skewer through the tape so that it’s dangling in the center of the glass but not touching the bottom. You might need to use an extra piece of tape around the skewer to keep it from dropping down.

  Once the sugar syrup has cooled (to avoid thermal shock breaking the glass), pour it into the glass. Cover with plastic wrap. Set the glass someplace where it won’t be disturbed and check it every day as the sugar crystals grow. Remove the skewer when the sugar crystals have reached the desired size.

  Note

  You can add food coloring to the water to make colored sugar crystals. Note that some food colorings are not suitable for vegetarians, such as red food coloring (cochineal or carminic acid), which is derived from the scales of an insect.

  Simple Lime Marmalade

  Marmalade is made by boiling sliced citrus fruits in sugar water and then adding pectin to cause the liquid to gel. For an intensely bitter marmalade—whether you like this style is a matter of personal preference—use Seville oranges. These can be hard to come by, which is why I suggest using limes here. Try this with other citrus fruits, or try a blend!

  In a saucepan, bring to a boil and then simmer for half an hour or so, until the rinds are soft:

  1 pound (400–500g) limes, cut in half lengthwise, then sliced thinly (about 6 to 8 limes’ worth)

  2 cups (500g) water, at least enough to cover limes

  1.5 cups (300g) sugar

  Once the fruit has softened, remove from heat. The marmalade should be intensely bitter at this point; you can add a bit more sugar if you find it overwhelming. Add pectin, following the directions on the box. If you’re using a highmethoxyl (HM) pectin, keep in mind that some amount of acid is needed for it to set; in contrast, low-methoxyl (LM) pectin requires a sufficient amount of sugar to set. If your marmalade or jams aren’t setting, you’ll need to either add something acidic for HM pectin (e.g., lemon juice) or sugar for LM pectin.

  Try making your own pectin! See Chapter 4 for details. Once you have the liquid pectin, just add it into the marmalade, simmering to reduce the liquid if necessary.

  Cool and store in fridge.

  Candied Orange Rind

  In a pot, bring to a boil:

  2 cups (475g) water

  2 cups (430g) sugar

  Orange rind from 3 to 6 oranges, cut into strips of width around 0.5 cm / ¼″

  Simmer for 20 to 30 minutes, until the rind is tender. Remove rind from pot, dry on paper towels, and transfer to a container. Add more sugar to container to help pull out moisture in the rind.

  Notes

  The bitter compound in citrus pith (or as a biologist would call it, the mesocarp) is limonin, which can be neutralized either by heat or by steeping in a base. Sugar is
used for its preservative qualities that prevent bacterial growth, not for counteracting the bitterness of the raw pith.

  Try other citrus fruits, such as grapefruit, lemon, lime, or tangerines; or fruits such as cherries, peaches, or apples. You can add spices such as cinnamon to the water as well, or substitute liquors such as Grand Marnier or dark rum for part of the water.

  You can chop up candied rind and use it in baked goods, or try dipping the candied rind in chocolate and serving it as a simple candy.

  Hervé This on Molecular Gastronomy

  PHOTOS USED BY PERMISSION OF HERVÉ THIS

  Hervé This (pronounced "teess") is a researcher at the Institut National de la Recherche Agronomique in Paris known for his studies of chemical changes that occur in the process of cooking. Along with Nicholas Kurti and others, he started a series of workshops entitled "International Workshop on Molecular and Physical Gastronomy," first held in 1992 at Erice in Sicily, Italy.

 

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