I'm Just Here For The Food Part 14

Olive-Stuffed Pork Loin Application: Brining and RoastingBrine the pork. Stir the sugars, salt, peppercorns and cider vinegar in a 4-quart saucepan over medium heat until everything is dissolved. Remove from the heat and add the ice. Stir until the ice has melted and the brine has cooled. Submerge the tenderloin in the brine and stash in the chill chest for 2 hours. Stir the sugars, salt, peppercorns and cider vinegar in a 4-quart saucepan over medium heat until everything is dissolved. Remove from the heat and add the ice. Stir until the ice has melted and the brine has cooled. Submerge the tenderloin in the brine and stash in the chill chest for 2 hours.Make the stuffing. Take the olives and olive oil for a spin around ye ole food processor until a semi-uniform paste is formed. Take the olives and olive oil for a spin around ye ole food processor until a semi-uniform paste is formed.Preheat the oven to 375F.Stuff the pork. Cut the tenderloin lengthwise down the center, but do not cut all the way through the meat; leave about inch connected. Make two more incisions on each side of the center cut; again leaving inch. Spread the olive paste into each groove and tie the loin with the butcher's twine to bring it back to its original shape. Place the tenderloin onto the rack set in the half sheet pan lined with parchment paper. Set on the center rack of the oven and roast for 25 to 30 minutes or until the meat reaches an internal temperature of 145F. Remove and rest at room temp for 10 minutes before slicing. Cut the tenderloin lengthwise down the center, but do not cut all the way through the meat; leave about inch connected. Make two more incisions on each side of the center cut; again leaving inch. Spread the olive paste into each groove and tie the loin with the butcher's twine to bring it back to its original shape. Place the tenderloin onto the rack set in the half sheet pan lined with parchment paper. Set on the center rack of the oven and roast for 25 to 30 minutes or until the meat reaches an internal temperature of 145F. Remove and rest at room temp for 10 minutes before slicing.Yield: 4 servings Software : 1- to 2-pound pork tenderloin, 1- to 2-pound pork tenderloin, trimmed of exterior fat, connective tissue and the like.

For the brine:1 cup dark brown sugar 1 cup sugar 1 cup salt 1 tablespoon black peppercorns 2 cups apple cider vinegar 1 pound ice cubes Forthe stuffing : cup green olives, pitted cup green olives, pitted cup kalamata olives, pitted 2 tablespoons olive oil Hardware : Cutting board Cutting board Chef's knife 4-quart saucepan Food processor Butcher's twine Half sheet pan Rack for half sheet pan Parchment Meat thermometer

CUTTING DIAGRAM.

Pickled Ginger (Gari) (Gari) Although most Americans know gari gari as the pink stuff on the side of the sushi plate, it can be consumed anywhere its sharp, sweet bite would be welcomed. I serve it with roast pork and fried chicken, and I've been known to chop it up in egg salad. When a brine has enough vinegar in it, we call it a "pickle." The result in this case is clearly a pickle. as the pink stuff on the side of the sushi plate, it can be consumed anywhere its sharp, sweet bite would be welcomed. I serve it with roast pork and fried chicken, and I've been known to chop it up in egg salad. When a brine has enough vinegar in it, we call it a "pickle." The result in this case is clearly a pickle.

Application: BriningPeel the ginger with the soup spoon. Thinly slice on the mandoline and place it in a 1-quart gla.s.s jar. Set aside.Combine the rice wine vinegar, sugar, and salt in a small saucepan and bring to a boil over medium-high heat. Remove from the heat and pour over the ginger in the jar. Cool, uncovered, for 30 to 40 minutes, then place in the refrigerator. Cover after 1 hour in the chill chest. Refrigerate for 1 week before using. If kept refrigerated, the pickles will keep until the end of time...or at least a month.Yield: 1 quartSoftware : 1 pound fresh ginger root 1 pound fresh ginger root 2 cups rice wine vinegar 1 cup sugar 2 teaspoons kosher salt Hardware : Soup spoon Soup spoon Mandoline (or other thin slicer) 1-quart gla.s.s canning jar, scrupulously cleaned 2-quart saucepan

Rhapsody for Red (Meat) This is a good marinade to use before any cooking method, but I prefer it for pieces that require a longer cook time-like lamb shoulder, which I marinate, sear, then wrap tightly in aluminum foil and cook for 2 or 3 hours at 300 F.

Application: MarinatingPlace all the ingredients in a lidded container and shake vigorously to combine. Place along with target meat in a large zip-top freezer bag. Seal the bag until almost closed. Insert plastic straw in remaining opening and suck as much air as possible from the bag. Seal the bag completely and refrigerate 2 to 8 hours.Remove the meat from the bag-do not rinse-and cook meat as desired.Note: This recipe makes enough marinade for a single flank steak. For more or less meat, increase or decrease the amounts proportionately. This recipe makes enough marinade for a single flank steak. For more or less meat, increase or decrease the amounts proportionately.Software : 4 tablespoons soy sauce 4 tablespoons soy sauce 4 tablespoons Worcestershire sauce 2 tablespoons red wine vinegar 2 tablespoons teriyaki sauce 2 tablespoons lemon juice 2 cloves of garlic, left whole but lightly crushed 1 tablespoon Dijon mustard 1 tablespoon extra-virgin olive oil Target cut of meat Hardware : Lidded plastic container Lidded plastic container Large zip-top freezer bag Plastic straw

Spice Rubs

I recently bought a jar of spice mix. The jar in question bore a bright, shiny, full-color photo of a smiling celebrity chef. The back label (in black and white) listed six ingredients, the first of which was salt. I bought one jar of the chef's mix as well as new containers of each of the spices listed in the ingredient roster. Once home, it took me about hour to replicate the mix. Using a pharmacy scale, I then calculated the amounts of each spice I used and the approximate cost. Now I know why the chef is smiling. I guess the people who buy this particular product a.s.sume the celebrity chef knows something they can never know and that knowledge justifies a 400 percent markup (make that 500 percent; those glossy, full-color photos are expensive). With the exception of Old Bay, chili powder, and the occasional curry powder, I try to steer clear of prepared spice mixes.

Don't get me wrong-I am a spice sn.o.b. I buy all my spices via the Internet or mail order. I know when I place an order with say, The Spice House or Penzeys Spices, I will get the best product available this side of the Spice Islands (see Sources). Sure, they might be a little pricey, but they're potent, which means I'll use less and therefore get more for my money. I avoid grocery store spices-there's just no way to know where they've been or how long they've been there.

Whenever possible I buy spices in their whole form. Like coffee, the minute a spice is ground it starts to lose its potency, so the less time that pa.s.ses between grinding and use, the better. Whole spices also have a much longer shelf life than ground, so less gets thrown away. To grind spices, use a clean pepper mill, or spice or coffee grinder (see Spice Rules Spice Rules).

If the spice in question is a seed (such as c.u.min, coriander, or sesame), I always toast them before grinding. This activates or "opens up" the essential oils that give the spices their distinctive flavors. To toast spices, heat a small saute pan, preferably non-stick, over medium-high heat and add the spice. Keep the pan moving to avoid burning. Toast until the spice is fragrant, but not browned, and transfer it to a plate to cool thoroughly (if ground when hot, the spices can steam inside the grinder and get gummy).

HERBS AND SPICES.

When the leaf of a plant is used as a flavoring agent, we call it an herb. Most herbs can be used in either their fresh or dry state. I'm not a huge fan of dry herbs unless they're headed for a soup or pot of spaghetti sauce. That's because I can add them near the beginning of the cooking process. Try that with fresh herbs and you'll find that whatever good they have to offer will disappear. By the same token, adding dry herbs at the end of cooking doesn't work because the pieces have to rehydrate before they can contribute anything in the way of flavor.When the dried seed, pod, root, or bark of a plant is used as a flavoring agent, it's a spice. Some plants render both. Cilantro, for instance, is a green herb most often found in Mexican dishes. The seed of the plant (technically fruit) is called coriander and most often finds itself in Asian fare...go figure.

ANOTE ON SALT.

Don't be scared by the amounts of salt in these recipes. Although salt will season the meat, its main purpose is to enhance the texture of the meat and make it more receptive to smoke; a key point in the barbecue world.

Although I'll keep whole spices like coriander around for up to a year and star anise and nutmeg even longer, ground spices and dry have a six-month life span at best. Buy some little circular labels at your local office Maxi-mart (usually located right next to the Mega-mart), stick one on the bottom of each container with an expiration date that's six months from the day you filled it. If the container's still full when that day comes, you might reconsider that spice's place in your kitchen.

And speaking of that place in your kitchen, proper storage of spices is key. That groovy spice rack with the retro gla.s.s vials may look spiffy but it's lousy food science. Spices hate light almost as much as they dislike air-so keep them tightly sealed and keep them out of sight. You also should fight the temptation to store spices in a drawer or cabinet near a heat source like an oven or dishwasher. Volatile acids vanish quickly in hot environments.

The Rub

Marinades can be wonderful, but when it comes to getting a lot of flavor onto meat quickly, spice rubs are the way to go. This is especially true if the meat in question possesses a relatively high surface-to-ma.s.s ratio (flank steak, skirt steak, chicken b.r.e.a.s.t.s, and tuna steaks are all good examples). And unlike marinades, rubs don't add to the preparation time of the meal.

Every single commercially available spice mix I've been able to get my hands on has listed salt as either the first or second ingredient. Salt content is a huge demon in the world of spice rubs and seasonings. Suppose you like the profile of a rub-say, its heat. You might think "I'll add more rub to make my food spicier." That seems logical, but it's also going to make it saltier.

That's why there is no salt in the ingredient lists of the recipes that follow. Add salt to the rub as needed-better yet, salt the food before you add the rub. Isn't it great to be in control of what you eat?

ESSENTIAL OILS.

Herbs and spices can bring flavor and aroma to foods because they contain powerful compounds referred to as essential oils, "essential" because they were once thought to hold the essence of the plant. These oils can be manufactured in just about any part of a plant: flowers smell pretty because of glands that produce oils in the base of the bloom; poison ivy makes you itch because of oils that spread out across the surface of its leaves. The flavor and aroma of spices are made possible by oil deposits in seeds (c.u.min), pods or fruits (nutmeg), bark (cinnamon), and even stems (sa.s.safras).In addition to flavorings, essential oils are used to odorize everything from perfume to paint. Essential oils also were the basis of many traditional medicines and were often used in dental products. (Remember the little bottle of clove oil Dustin Hoffman kept in his pocket after being "worked on" by Laurence Olivier in Marathon Man Marathon Man?)Essential plant oils, whether from orange zest or coriander seeds, are highly volatile, that is they evaporate very quickly when exposed to the air. The problem is, you have to grind them to get their full flavor and aroma-and that's about as exposed to air as you can get. What can you do? (See Spice Rules.)

There's a reason why they call it a rub. Many recipes call for seasonings to be sprinkled onto the target food. But it's not enough. Once you've liberally sowed the surface, ma.s.sage that rub into the meat-work it into those nooks and crannies. Most of this "first strike" will seem to magically disappear. Let it rest for a few minutes and the salt that first went onto the meat will pull moisture to the surface, providing fertile ground for another strafing of goodness. Depending on the concentration of flavor desired, this process can be repeated up to five times.

The choice of rub depends not only on the target food but on the cooking method as well. For instance, I wouldn't use the same rub on ribs that I intended to braise as a piece of tuna I intended to sear. For one thing, they have different flavor and texture profiles. The rub that is used on the Blackened Tuna Steak Blackened Tuna Steak doesn't need the a.s.sistance of fat to release its flavor, so it's perfect for the relatively lean fish. The pepper and chile flavors in the rub for doesn't need the a.s.sistance of fat to release its flavor, so it's perfect for the relatively lean fish. The pepper and chile flavors in the rub for No-Backyard Baby Back Ribs No-Backyard Baby Back Ribs not only foil the fattiness of the meat, but some of the ingredients (such as capsaicin, the hot stuff in chiles) are fat-soluble as well, so their flavor is actually activated by the fat as it cooks out of the meat. not only foil the fattiness of the meat, but some of the ingredients (such as capsaicin, the hot stuff in chiles) are fat-soluble as well, so their flavor is actually activated by the fat as it cooks out of the meat.

If you intend to dry sear your target meat, you might want to avoid spices that turn bitter in the face of high heat, specifically black pepper and anything containing chiles, including bell pepper. Of course the blackening craze of the 1980s gave some folks a taste for burned, so if you like carbon...well, it's your food.

These rubs are easy to make, but you don't just get to throw all the spices together and be the hero. Most of the spices need to be toasted separately, then cooled thoroughly prior to being ground and mixed. This is a bit more work, but the result will be more p.r.o.nounced flavors. Note that once toasted, spices will only keep for three months-and only if tightly sealed.

SPICE RULES.

DON'T: * * buy spice sets just because you like the packaging. buy spice sets just because you like the packaging. * * name music groups or any members thereof after spices. name music groups or any members thereof after spices. * * buy spices in bulk unless you've got a darned good reason...like you own a restaurant, barbecue compet.i.tively, or are working on a remake of buy spices in bulk unless you've got a darned good reason...like you own a restaurant, barbecue compet.i.tively, or are working on a remake of Dune Dune. * * store spices where you can see them. store spices where you can see them. * * store spices near heat sources. store spices near heat sources.

DO: * * buy whole (rather than ground) spices. buy whole (rather than ground) spices. * * keep an extra pepper grinder around for grinding small amounts of spice. keep an extra pepper grinder around for grinding small amounts of spice. * * keep an inexpensive electric coffee grinder around for grinding larger amounts of spice. keep an inexpensive electric coffee grinder around for grinding larger amounts of spice. * * make your own spice mixes. make your own spice mixes. * * Mount the center grind shaft of a pepper grinder to a battery-powered drill or screwdriver. It's a very effective way to grind spices. Mount the center grind shaft of a pepper grinder to a battery-powered drill or screwdriver. It's a very effective way to grind spices.

Chicken Rub Rubs really need high heat to "activate" their flavors, so this is best used with recipes for seared, grilled, or roasted chicken. Here's one: rub a chicken breast with this spice mixture, then pan sear it, and slice the finished chicken into strips to serve over pasta.

Application: Rub RubToast the spices separately as described in Spice Rubs Spice Rubs, using a small nonstick saute pan, then grind in a spice or coffee grinder.Combine all the ingredients in a mixing bowl, then transfer to an airtight storage container for up to 3 months. When you're ready to use the rub, add salt as necessary.Notes: The measurements in all of the rub recipes are provided as ratios: just make sure you stick to one measuring device (thimble, ladle, dump truck) and the result will be perfect. I generally use a 2-ounce ramekin. For this Chicken Rub, use half a ramekin of toasted ground fennel seeds, 1 full ramekin of toasted ground coriander seeds, half a ramekin of toasted ground c.u.min seed, and so on. Note that these proportions are based on ground-not whole seed-quant.i.ties, so measure the spices after they're ground. The measurements in all of the rub recipes are provided as ratios: just make sure you stick to one measuring device (thimble, ladle, dump truck) and the result will be perfect. I generally use a 2-ounce ramekin. For this Chicken Rub, use half a ramekin of toasted ground fennel seeds, 1 full ramekin of toasted ground coriander seeds, half a ramekin of toasted ground c.u.min seed, and so on. Note that these proportions are based on ground-not whole seed-quant.i.ties, so measure the spices after they're ground.As far as chile powder is concerned, I try to always use those that are pure. For example, a powder that is made of nothing but pa.s.sila chiles is better than a mixture of several varieties (along with who-knows-what other spices and fillers).Software : part toasted ground fennel part toasted ground fennel seeds (see Notes Notes) 1 part toasted ground coriander seeds part toasted ground c.u.min seeds part toasted ground celery seeds part toasted ground white peppercorns part toasted ground black peppercorns part toasted ground red pepper flakes 1 part dried, rubbed sage 1 part file powder 1 part ground dried onion flakes part chile powder (I use pa.s.sila; see Notes Notes) 1 part confectioners' sugar part garlic powder part ground cinnamon Hardware : Small saute pan, preferably Small saute pan, preferably non-stick Spice or coffee grinder Mixing bowl Airtight storage container

This rub is amazingly good on popcorn.

Fish Rub This is great for grilling, broiling, and blackening all types of fish, and it's also good on shrimp, scallops, and lobster. Just keep in mind that rubs require high heat to "activate" their flavors.

Application : RubToast the spices separately as described in Spice Rubs Spice Rubs, using a small non-stick saute pan, then grind them in a spice or coffee grinder.Combine all the ingredients in a mixing bowl, then transfer to an airtight storage container for up to 3 months. When you're ready to use the rub, add salt as necessary.Software : part toasted ground fennel part toasted ground fennel seeds (see Notes Notes) part toasted ground c.u.min seeds 1 part toasted ground celery seeds part toasted ground white peppercorns part toasted ground black peppercorns part toasted ground red pepper flakes part confectioners' sugar part paprika part garlic powder 1 part ground dried onion flakes 1 part chile powder (I use guajillo; see Notes Notes) part file powder Hardware : Small saute pan, preferably Small saute pan, preferably non-stick Spice or coffee grinder Mixing bowl Airtight storage container

Beef Rub This is great for pan-searing, grilling, blackening, or broiling just about any cut of beef. Just remember that rubs need a high-heat cooking method to "activate" their flavors.

Application: RubToast the spices separately and grind them as described in Spice Rubs Spice Rubs, using a small non-stick saute pan and a spice or coffee grinder. Combine all the ingredients in a mixing bowl, then transfer to an airtight storage container for up to 3 months. When you're ready to use the rub, add salt as necessary.Software : 1 part toasted ground coriander 1 part toasted ground coriander seeds (see Notes Notes) 1 part toasted ground c.u.min seeds part toasted ground celery seeds part toasted ground white peppercorns part toasted ground black peppercorns part toasted ground red pepper flakes part confectioners' sugar part garlic powder 1 part mild chile powder (I use New Mexico; see Notes Notes) part ground dried onion flakes part file powder part dried rubbed sage Hardware : Small saute pan, preferably Small saute pan, preferably non-stick Spice or coffee grinder Mixing bowl Airtight storage container

Haste Makes Paste A rub and a marinade in one, use this for roasts that will be broiled, grilled, or-roasted. It's not pretty (the paste will burn in places), but the meat will be delicious, especially if the meat is lamb. The paste will also make a mess of the grill (it will stick, but the meat won't). I usually fire up some extra charcoal and throw it right on the cooking grate just after I remove the meat. The charcoal burns off the offending residue and then falls through to the bottom grate-no muss, no fuss.

Application: RubPlace the garlic in the bowl of a food processor and finely chop. Add the remaining ingredients and process to a pastelike consistency.Rub the mixture over the entire surface of the target meat, cover, and refrigerate from 4 hours to 2 days. Cook as desired.Do not add any more paste once the cooking begins.Software : 4 cloves of garlic 4 cloves of garlic 10 mint leaves 1 tablespoon dark brown sugar 1 tablespoon kosher salt 2 teaspoons freshly ground black pepper 6 tablespoons strong mustard Target meat Hardware : Food processor Food processor

CHAPTER 8.

Sauces

Once used to smother the taste of spoiled food, now used to enhance natural flavors.

All the World's a Sauce

By and large, most home cooks don't do sauce... and that's too bad. Traditional sauces are indeed scary-as all dinosaurs (even the cute ones) are. They're scary because they are not of our time. They are of a time when toqued Frenchmen walked the earth, backed by armies of fourteen-year-old apprentices who probably didn't live to see forty because the air in the kitchens, with their wood-burning ovens, would rot their lungs. The kitchens these culinary T-Rexes occupied bear no resemblance to the rooms we cook in, nor did the groceries that filled them. These guys worked with whole everything: they didn't buy a steak, they bought a side of beef. They didn't buy a fish filet, they bought the fish. They purchased cartloads of produce and had that army of apprentices at the ready to clean it all. This meant a lot of leftovers: meat sc.r.a.ps and bones and fish heads, carrot tops, mushroom stems-that sort of thing. Being clever and innovative, the ancient chefs didn't want to waste these items. They made sauces, and everyone was happy.

Fast-forward a couple hundred years and people are still buying books packed with recipes for the mother sauces and their archaic offspring. This makes about as much sense as going to the barber to have leeches slapped on a wart.30 Still, there are lessons to be learned from les dinosaurs les dinosaurs. They made sauces out of leftovers and so should we, as long as the process doesn't require that you hire a brigade of a.s.sistants.

Most cla.s.sical sauces fall into these extremely overgeneralized categories: * Sauces based on stocks* Sauces based on emulsions* Sauces based on roux

A stock is a liquid in which collagen from animal bones and connective tissue has been dissolved and converted into a protein matrix called gelatin. Broth and stock are not the same thing. A broth is essentially any liquid that's had food cooked in it, be it meat or vegetables. Bones are not required for a broth, but they are for a stock. Thus, there is no such thing as vegetable stock. is a liquid in which collagen from animal bones and connective tissue has been dissolved and converted into a protein matrix called gelatin. Broth and stock are not the same thing. A broth is essentially any liquid that's had food cooked in it, be it meat or vegetables. Bones are not required for a broth, but they are for a stock. Thus, there is no such thing as vegetable stock.

An emulsion is a colloid is a colloid31: two liquids, which do not like each other, are forced into a colloidal relationship via dispersion of one into the other in the form of microscopic droplets. Vinaigrette dressings are temporary emulsions; unless there is an emulsifier present (such as lecithin or Polysorbate 80, for instance, or pulverized vegetable matter, like mustard) vinaigrettes will always separate in the end. Mayonnaise and hollandaise are also oil-in-water emulsions (mayo is raw, hollandaise cooked), but they are more stable than vinaigrettes because of emulsifiers present in the egg yolks. b.u.t.ter is an emulsion made up of water droplets in fat.

A roux is an equal mixture of starch (usually from wheat flour) and fat, which are mixed together and cooked. A flavorful liquid is then added and the starch particles, encased in the fat, are free to be distributed in the liquid. With the addition of heat, they swell and burst, thickening the liquid. American gravy (the kind usually served at Thanksgiving), "sawmill" gravy, and most pan gravies are examples of roux sauces. is an equal mixture of starch (usually from wheat flour) and fat, which are mixed together and cooked. A flavorful liquid is then added and the starch particles, encased in the fat, are free to be distributed in the liquid. With the addition of heat, they swell and burst, thickening the liquid. American gravy (the kind usually served at Thanksgiving), "sawmill" gravy, and most pan gravies are examples of roux sauces.

Stock

I don't make stock often, but when I do I always feel like I've gotten away with something, like I've pulled some kind of alchemical con job on nature.

Stocks have always provided a way to juice a little more value out of the ingredients on hand. Veal bones are a pretty terrific source of collagen, but I rarely have a cow carca.s.s lying around the house. I do, however, have chicken bones, hen bones, and duck bones from time to time-and a freezer to store them in.

When I've got five or six racks of chicken plus a couple of duck carca.s.ses, I break out my biggest pot and a pair of tin snips. Since smaller pieces mean faster collagen extraction, I break the frozen carca.s.ses into pieces (if they're too tough, I use the snips) and add them to the pot. I add enough cold water to cover the bones and bring to a boil.

Now here's the screwy part. Collagen is not the only thing in the pot. Many other water-soluble substances will emerge from the bones once the water hits a boil. They will collect at the top of the pot and, since their presence serves to reduce the surface tension of the water, once water vapor starts to rise from the bottom, there's going to be a whole lot of foaming goin' on. Ever seen foam riding the waves on a windy day at the beach? Same stuff.

As soon as it does, drop the heat so that you maintain a low boil.

Many stock makers, wishing to discard this foam, turn to slotted spoons, ladles, you name it. I use one of those little square nets they use to catch neon tetras down at the pet store. As soon as I get a big netfull I unload it by turning it upside down under cold running water. After five minutes or so of defoaming, stop and watch. Odds are you'll be in the clear and can go ahead and toss in a couple of quartered onions, a couple of carrots split down the middle, at least three ribs of celery broken in half, and a palmful of black peppercorns. No green herbs yet. And no salt.32 THE WHOLE BIRD.

One of the reasons I always buy whole chicken is to get the rack: the carca.s.s, complete with wings, rib cage, and backbone.32 There are, of course, other reasons to buy whole: There are, of course, other reasons to buy whole: * * The less processing a food has undergone, the cheaper its per-pound price will be. The less processing a food has undergone, the cheaper its per-pound price will be. * * All things being equal, whole birds will keep longer than pieces will. All things being equal, whole birds will keep longer than pieces will. * * Many meat cutters hack the pieces apart instead of taking the time to separate them at the joints. Many meat cutters hack the pieces apart instead of taking the time to separate them at the joints.

So in buying a whole bird you pay less money and get all those great pieces to make stock with. I make stock only a few times a year, so I bag, tag, and freeze the bones as I gather them. (A chest freezer in the bas.e.m.e.nt is a wonderful thing.) SURFACE TENSION.

It was in 1751 that Johann Andreas von Segner, a German physicist and mathematician, first introduced his ideas about the surface tension of liquids. Today, we understand that molecules at the surface of a liquid attract each other to create something that's been referred to as like a skin or a stretched membrane. (It's because of this tendency that some insects are able to stand on the surface of a pond.) Water molecules are so attracted to each other that when presented with a different environment, such as air, they will shape themselves into spheres to expose as few molecules as possible to that environment. It's easy to find an example of this phenomenon right at home in your kitchen. Check out a slowly dripping faucet. As the drops of water form, they sag or stretch out into almost a teardrop shape before falling.Surface tension explains why pure water cannot be bubbled or persuaded to foam. And this goes not only for water but also for any pure liquid. To coax water into foaming, you have to break the tension by adding something that can work its way into the water.