History of the Hamburger
The origin of the hamburger is suggested to be nomadic Mongolian and Tartar warriers who loved the taste of raw meat. They would tenderize filets of meat by placing them under the saddles of their horses while riding — I bet that was tasty!
Sailors at the port of Hamburg Germany were said to enjoy a meal of a thin patty of ground beef sausage fried in butter. The patty was served with a fried egg on top of the patty between two slices of lightly buttered bread. The sandwich was known as Deutsches Beefsteak. Supposedly, when sailors visited the port of New York, word of the Deutsches Beefsteak spread and sailor began to ask for "hamburgers". The term "hamburger" appeared on a menu (believed to be printed in 1834) from Delmonico's restaurant in New York, but, technically speaking, the Delmonico hamburger was not a "real" hamburger because it was not served between slices of bread.
The State of Wisconsin claims to be the "Home of the Hamburger" — They claim that the hamburger originated from a 15-year old boy named Charlie Nagreen. Charlie had a stand at the Outagamie County Fair to sell meatballs. Charlie soon learned that his meatballs were of little value to his customers, simply because they were difficult to eat while trying to enjoy the fair. So Nagreen flattened the beef and placed it between two slices of bread. And that was the first hamburger. His idea was a success and soon he was known to many as "Hamburger Charlie." Charlie returned to the fair every year until his death in 1951 and he would entertain people with guitar and mouth organ and his jingle:
Hamburgers, hamburgers, hamburgers hot; onions in the middle, pickle on top. Makes your lips go flippity flop.
Charlie Nagreen's hometown of Seymour, WI honored Charlie with the Hamburger Hall of Fame located at 126 North Main Street, Seymour, WI, USA. Seymour also holds multiple titles for the world's largest hamburger — The latest being an 8,266 pound burger cooked at Burger Fest on August 4, 2001.
In the 1890s, "Hamburg steak" referred to a piece of beef that had been pounded and tenderized rather than a ground beef patty. In Mrs. Rorer's New Cook Book (1902), Hamburg steak is described as beef put twice through a meat grinder and mixed with onion and pepper, closer to the present day hamburger.
By 1912 ground meat patties were being served in buns, and according to "The American Dictionary of American Slang", the suffix "burger" came to mean "any hot sandwich served on a bun, often toasted, with many condiments...." White Castle opened their first "hamburg stand" in 1921 in Wichita, Kansas, and the popularity of the hamburger grew as Americans took to the roads. In the 1950s the McDonald's chain began, spawning dozens of competitors.
According to "The American Dictionary of Food and Drink", Americans eat three hamburgers per week per person! This is about 38 billion annually, or 59 percent of all sandwiches consumed.
Selecting and Safely Handling Hamburger Meat
Below are some guideline for selecting and safely handling meat for hamburgers.
It is the fats in ground meats that make burgers juicy, and the lean that makes it meaty and satisfying. Use 80% lean ground beef or chuck.
"Hamburger" meat found in grocery stores may have added beef fat up to 30% by weight. "Ground Beef" will never have added beef fat.
Don't fall for "lean" or "extra-lean" ground beef — Always consider that percentage of fat. In order to be labeled "lean", the ground beef must have 25% less fat than standard ground beef's 30% limit. After doing the math, this means that to be labeled "lean", the ground beef can contain no more than 22.5% fat. Would you call that "lean"?
If you want to use leaner ground beef, try adding a little raw egg, tomato juice, Worcestershire sauce, or steak sauce to the ground beef to maximize the juiciness and flavor. Use breadcrumb to balance the added moisture.
For the best taste and optimum freshness, connoisseurs recommend organic ground beef. USDA-certified organic ground beef is made from animals that have not been injected with synthetic hormones or antibiotics, and that eat food free of animal byproducts and grown without pesticides.
The best burgers are all beef. The purity of ground beef is always better than "meatloaf burgers" in which vegetables and other ingredients are mixed with the ground meat. Use toppings and condiments to make the burger more exciting.
If you are concerned about cholesterol, you should know that beef flesh and beef fat contain about the same amount of cholesterol. This means a standard ground beef patty could potentially have slightly less cholesterol than the equivalent lean ground beef patty after cooking.
If you can get the butcher to grind the meat for you instead of picking prepacked ground beef, you know you're getting freshly ground beef and your burgers will probably taste better.
At the store, to choose a package of hamburger that's not torn and that feels cold. If possible, enclose it in a plastic bag so juices won't drip on other foods. Make ground beef and other perishables your final purchase of the trip.
The bright red color of ground beef is often used by consumers as a selection factor when purchasing hamburger, but a dark gray-purple color may not necessarily be a bad thing. All warm-blooded animals contain a pigment called myoglobin in meat tissues. Myoglobin is the primary oxygen-carrying pigment of muscle tissues. It is normally a dark grayish-purple color, but when it comes in contact with oxygen, it becomes oxymyoglobin and reacts by turning a deep red color. Meats that are vacuum-packed have not been exposed to oxygen long enough to turn red. It is for that eye-pleasing coloration that most fresh ground beef sold in clear packages at the market is packaged using a clear film that is oxygen permeable. The oxygen goes through the film and allows the meat to turn that pretty red color we associate with fresh beef. This is why it is not recommended to freeze meat in store packaging. Coloring can also indicate spoilage. If your package of ground beef is grayish all the way through and does not turn red when exposed to air for fifteen minutes or so, it is most likely spoiled. Usually your nose will tell you right off the bat, as spoiled ground beef will smell sour. It will also feel tacky to the touch. Don't take any chances with spoiled meat. When in doubt, toss it out.
Grinding meat makes it more tender, but the grinding process exposes more surface area of the meat to possible contamination. Bacteria multiply rapidly in the "danger zone" between 40 and 140°F. Store ground beef at 40°F and use or freeze it within two days.
After leaving the store, get perishables home quickly and refrigerate or freeze immediately. If your trip home will take longer than an hour, pack meats in ice in a cooler chest, especially in summer heat.
To freeze ground beef, remove from market packaging and divide into specific recipe portions. Wrap in plastic wrap or foil and place in airtight plastic sealed bags. Burger patties can be formed, separated by butcher paper or plastic wrap, sealed in a baggie and frozen for quick individual meals.
Ground beef kept frozen at 0°F should be safe for up to four months.
To thwart the growth of bacteria, it is essential to keep meat cold while defrosting. Never leave frozen meat out on the counter for more than two hours. Plan in advance to slowly thaw it in the refrigerator instead.
When handling raw beef, don't let raw juices contaminate foods that won't be cooked. Wash your hands with soap and hot water before and after handling raw beef to make sure you don't spread bacteria from one surface to another. The same goes for utensils and surfaces that have come into contact with the raw meat.
To avoid ground beef sticking to your hands, dip your hands in clean, cold water before handling the meat.
Don't reuse packaging materials.
When taking meat off the grill, don't put the cooked meat on the same platter that held the raw meat.
To be sure bacteria are destroyed, cook hamburgers to 160°F (medium doneness) or until the center is no longer pink and the juices are clear .
The color of cooked ground beef can be quite variable and it is not an accurate indicator that the meat is thoroughly cooked. At 160°F, a safely cooked patty may look brown, pink, or some variation of brown or pink. Many factors influence the color of the meat — Raw beef reflects green light at approximately 560nm which gives it its red color. The color that meat takes is partly determined by the charge of the iron atom in myoglobin heme and the oxygen attached to it. When meat is in its raw state, the iron atom has a charge of +2 and is bound to O2, an oxygen molecule. Meat cooked well done is brown because the iron atom has a charge of +3, having lost an electron, and is now bound to a water molecule (H2O). Under some conditions, meat can also remain pink all through cooking, despite being heated to high temperatures. If meat has been exposed to nitrites, it will remain pink because the iron atom is bound to nitric oxide (NO) — For example, corned beef or cured hams. Grilled meats can also take on a pink "smoke ring". Meats cooked over wood, charcoal, or gas flames—barbeque pork or beef, for example, or even poultry cooked in a gas oven—often develop "pink ring," which reaches from the surface to a depth of 8-10mm. This is caused by nitrogen dioxide (NO2) gas, which is generated in trace amounts (parts per million) by the burning of these organic fuels. It appears that NO2 dissolves at the meat surface to form nitrous acid (HNO2), which diffuses into the muscle tissue and is converted into nitric oxide (NO). NO in turn reacts with myoglobin to form a stable pink molecule. Raw meat packed in a carbon monoxide atmosphere also shows this same pink "smoke ring" due to the same molecular process. Notably, the surface of the raw meat also displays the pink color, which is usually associated in consumers' minds with fresh meat.
The only accurate method to ensure the meat is done, is to measure the temperature of the cooked meat — Use a digital instant-read food thermometer. Toward the end of the cooking time insert at least ½ inch into the thickest part of the patty. If the ground beef patty is not thick enough to check from the top, the thermometer should be inserted sideways. If uncertain about the temperature reading, take a reading in a second location. Try to minimize the number of times you have to stick the temperature probe in the burger. The more you stab your burger, the more juices you'll lose.
Another option for testing the internal temperature of your burger is to use a T-Stick ®.
One way to enjoy a less risky rare hamburger is to grind the meat yourself after a quick treatment that will kill surface bacteria. Bring a large pot of water to a rolling boil, immerse the pieces of meat in the water for 30-60 seconds, then remove, drain and pat dry, and grind in a scrupulously clean meat grinder. The blanching kills surface bateria while overcooking only the outer 1-2 millimeters, which grinding then disperses invisibly thoroughout the rest of the meat.
If you don't have a meat grinder, use a clean food processor — Pulse the food processor exactly 10 times, 6 times for steak tartare. More than 10 is way too fine, and you'll end up with a dense meat brick instead of a hamburger.
Never partially grill extra meat for later use. Once you begin cooking meat, cook until completely done to ensure that bacteria are destroyed.
Any leftover meat left out at room temperature for more than two hours should be discarded.
Cooked beef can be stored in the refrigerator for three days or frozen for up to three months. For further information about handling and cooking hamburgers safely, call USDA's Meat and Poultry Hotline at 1-800-535-4555 or visit www.usda.gov.
Shaping a Hamburger
Hamburger recipes repeat, "do not overhandle meat"! If you shape a burger into a compressed, dense burger, you are going to have a compressed, dense, tough burger after you cook it. The red lean and flecks of white fat should be distinctly visible in the patty. When the patty is compressed too much, the red lean and white flecks of fat meld into a pink blur,
Look at the patties in the image below  — The one on the bottom has been kneaded and compressed into shape. The one on the top, however, was (keyword, here) "gently" pressed into shape.
When shaping hamburger patties, remember that there's more shrinkage in higher-fat meats than lean meats. So, when using ground chuck or regular ground beef, form the patties slightly larger than the diameter of the hamburger bun-they'll shrink down to just about the right size.
Patty Size A Hamburger Today poll indicates some people like diminutive sliders, while for others, the bigger the better. 5 ounces, the size favored by reputable joints such as Bill's and Le Parker Meridien's Burger Joint, was the happy medium. And the people wisely decided to form the patty ½ an inch thick, a size which maximizes surface area browning, while still being thick enough to offer a medium rare center. A preference for 8 ounce burgers was narrowly voted as the number two favorite size.
Make a Dent
A hamburger patty, properly shaped will puff up as it cooks. This happens because the collagen  in the meat shrinks when heated. A collagen molecule resembles a stretched-out spring. When heated to approximately 130°F, the bonds keeping the spring taut are released, and it snaps into a jumbled coil, shriveling the tissue. The top, bottom, and side of a hamburger patty receive the initial heat from the grill. When the sides heat up and the collagen tightens the meat in the patty is forced up in the middle of the patty.
By making depressions in the patties with "gentle" pressure from your fingers, the resulting burger (below), while thick, is also flat and evenly cooked. 
Patties made with the same amount of meat but formed without a depression, such as those below, resulted in burgers with a distinct bulge in the center.
In Cooks Illustrated taste tastes, the best hamburgers were found to be approximately 6 ounces and 4½ inches in diameter and ½ inch thick.
Cross-contamination is the bacterial contamination of a food product from another source. There are three main ways cross contamination can occur:
Food to Food
Equipment to Food
People to Food
Food to Food Contamination
Food can become contaminated by bacteria from other foods. This type of cross contamination is especially dangerous if raw foods come into contact with cooked foods. Here are some examples of food to food cross contamination:
In a refrigerator, meat drippings from raw meat store on a top shelf may drip onto cooked vegetables placed on a lower shelf.
Raw chicken placed on a grill touching a burger that is being cooked.
Equipment to Food Contamination
Cross contamination can also occur from kitchen equipment and utensils to food. This type of contamination occurs because the equipment or utensils were not properly cleaned and sanitized between each use. Some examples are:
Use unclean equipment such as slicers, can openers and utensils to prepare food.
Using a cutting board and the same knife when cutting different types of foods, such as cutting raw chicken followed by salad preparation.
Storage of a cooked product, such as a sauce, in an unsanitized container that previously stored raw meat.
People to Food Contamination
People can also be a source of cross contamination to foods. Some examples are:
Handling foods after using the toilet without properly washing your hands.
Touching raw meats and then preparing vegetables without washing hands between tasks.
Using an apron to wipe your hands between handling different foods, or wiping a counter with a towel and then using it to dry your hands.
Preventing cross contamination
Follow these steps to prevent cross contamination and reduce hazards to food:
Keep the meat as cold as possible.
Wash your hands between handling different foods.
Wash and sanitize all equipment and utensils that come in contact with food.
Avoid touching your face, skin and hair or wiping your hands on cleaning cloths.
Store foods properly by separating washed or prepared foods from unwashed or raw foods.
Try preparing each type of food at different times and then clean and sanitize food contact surfaces between each task.
Cooking a Hamburger
Hamburgers should be cooked on a medium-hot fire—If you can only hold the palm of your hand about 5 inches over the grill for a few seconds, the fire is ready. Gently place the hamburgers on the grill and cook 2 to 4 minutes per side, depending on the heat of the grill.
Here are some tips for cooking your hamburger:
Don't undo all your effort to prepare the ultimate burger! Don't press the burger on the grill with your spatula to make it cook quicker or flatten it — All you're doing is squeezing the good juices out of the meat!
Salt your burger after you cook it because salt draws moisture out of the meat.
The burger is going to shrink — The higher the heat, the more the burger will shrink. The amount of shrinkage is going to also depend on fat and moisture content, but cooking at moderate temperature over medium-hot coals will help retain juices and flavors.
Don't overcook the meat! Overcooking draws out more fat and juices from ground beef, resulting in a dry, less tasty product.
Lightly grease the grill rack with power towls dipped in oil. This will help the crust stick to the patty instead of the grill rack.
Gently flip burgers with a spatula. Never jab the patty with a fork to turn it — You'll lose juices.
Only flip the burgers one time. To form a good crust, set the patty on the grill and leave it alone for several minutes.
Don't overlook the rolls. Ideally, the rolls should be soft and chewy with a light toast.
Properly melt the cheese. There is nothing worse than a burger with half melted cheese. Trap the heat by closing the grill over the patties. If cooking indoors, place a metal bowl over the burgers to melt the cheese.
What's the Best Cheese for Cheeseburgers?
On the 4th of July, we Americans don't merely celebrate our country's independence from the British Empire—we also pay our humble respects to that most American of comfort foods: the cheeseburger. But what types of cheeses work best? As I see it there are three variables to consider: meltability, tanginess, and the funk factor. Some choose to optimize for one of these variables, but there may be a perfect cheese to satisfy all three.
If you're going to go for cheeses that melt perfectly, processed cheese is the way to go. Whether it's Velveeta or Kraft American Singles, processed cheeses make up for their bland flavor with undeniably superior meltability. (They contain added emulsifiers which help prevent the separation of water, fats, and proteins when heat is applied.) Processed cheeses are also the way to go if you want to really showcase the flavor of the meat—the cheese will add a nice texture to the sandwich without interfering taste-wise. However, there are other meltable cheeses that potentially have much more flavor: Gruyère, Comté, Brie, Taleggio, Fontina, and many more.
If you're willing to forgo some of the smoothness of the cheeses listed above, and would rather have your cheese add a sharp bite to the sandwich, your best bet is to go for an aged Cheddar, Monterey Jack, aged Provolone, or even Parmigiano-Reggiano. While some of these cheeses may separate a bit when hot, they are also much more flavorful than your average processed cheese. Tangy cheeses also tend to balance the savoriness of the meat really well.
The Funk Factor
If you really want a cheese that will contribute a great deal of flavor to the overall cheeseburger experience, go for a blue. It is best to choose a blue that is fairly rugged so that you don't end up with a saucy mess. Think Maytag Blue rather than Gorgonzola. If you go the blue route, don't be upset if all you taste is the cheese—blue cheese is super strong and will often overpower the subtle flavors of the meat. But if funkiness is your thing, a blue cheeseburger can be a revelatory experience.
Ultimately I think that a really good aged Gruyère or Comté is the best way to go if you want to maximize all three factors. These Swiss/French Alpine cheeses melt really well (they are the fondue cheeses after all), they have a little bit of tang, and if you find the right specimen they can add that nice funky edge as well.
Let your burger rest after you remove it from the grill — A minute or so is fine. Flip it halfway through the rest period so the juices get distributed.
You always build a perfect hamburger from the bottom up:
Start with the bottom part of the hamburger bun. Place the cooked burger on top of it. The bottom part of the hamburger bun is going to absorb the juices from the burger and retain a lot of flavor.
To toast hamburger buns, either place face down on the grill or face up in the broiler or toaster oven for approximately one minute.
Salt and pepper the burger.
Add the cheese. Always add the cheese on top of the cooked burger. If you place the cheese between the burger and the bun, the juices and flavor from the hamburger will drip out! It's best to cut cheese while it's cold, but let it stand at room temperature for at least one hour before serving to allow flavors to bloom. If you want the cheese melted, place it on top of the burger during the last 1 to 2 minutes of cooking.
Add onion and tomato. The tomato reduces the strong almost over powering onion taste.
Use ketchup, mustard, Thousand Island dressing, or mayonnaise on the top part of the hamburger bun, or squirt or spoon on the vegetables.
You need enough fresh lettuce to elicit crunch, enough tomato to sweeten the deal, enough onion to bring heat, and only enough sauce to lend flavor.
Add the top of the hamburger bun.
Footnotes 1 Source: Bobby Flay seminar at the Food and Wine Classic 2008 in Aspen, CO 2 Undercooked meat may contain harmful bacteria, and the very young, the very old, and those with immune systems that have been weakened by cancer, kidney disease, and other illnesses are most at risk and vulnerable to illnesses associated with contaminated food. The symptoms of foodborne illness — such as diarrhea or vomiting, which can cause dehydration — can be very serious. Safe food handling practices at home or anywhere food is served is especially important for those in the "at-risk" group.
3 Source: On Food and Cooking by Harold McGee 4 Source: GOURMET, June 2002, p155
5 Collagen is the main protein of connective tissue. It has great tensile strength, and is the main component of ligaments and tendons. It is responsible for skin elasticity, and its degradation leads to wrinkles that accompany aging.
6 Source: COOK'S ILLUSTRATED, July & August 2000, p7
7 Source: "What's the Best Cheese for Cheeseburgers?", Posted by Jamie Forrest, July 2, 2008 at 1:15 PM, A Hamburger Today