In-N-Out Burger products
When In-N-Out Burger first opened in 1948, the company only provided a basic menu of burgers, fries and beverages. The foods it prepared were made on-site from fresh ingredients, including its french fries which were sliced and cooked to order. Unlike other major competitors in the hamburger fast food restaurant business (Burger King, McDonald's and Wendy's), as the chain expanded over the years, it has not added products such as chicken or salads to its menu or changed its preparation methods.
Instead of a broad menu like other competitors, In-N-Out has become known for its Secret Menu, unadvertised variations of its burgers that are based on customer preferences, such as the popular "Animal Style."
All burgers consist of one or more 1/8 lb beef patties cooked to "medium-well", and served on a toasted bun. The standard style of burger includes tomato, hand-leafed lettuce and "spread", a sauce similar to Thousand Island dressing. In addition, customers are asked if they wish to add raw or grilled onions.
The bulk of the secret menu revolves around the burgers. In-N-Out's own website acknowledges the existence of this secret menu, publicizing "some of the most popular items" on what it calls the company's "not-so-secret menu."
"Animal Style" is one of the most popular "secret" styles; in addition to the standard toppings, Animal Style burgers include pickles, extra spread, grilled onions, and mustard fried onto each meat patty. "3×3" (pronounced 3-by-3), "4×4", or variations of "m" × "c", refers to a burger with a varied amount of meat patties, "m", and slices of cheese, "c": e.g. a burger with six meat patties and three slices of cheese is a "6×3". The In-N-Out "secret menu" section of the website only mentions the "3x3" and "4x4", which are registered trademarks of the company.
4x4 is the largest burger that In-N-Out currently makes. However, there have been instances of much larger sandwiches. On October 31, 2004, a group of friends ordered a 100x100 from a location in Las Vegas, Nevada, posting photos on the web of the burger.
In-N-Out has two low carbohydrate offerings, akin to the Atkins diet. "Protein Style", introduced in the 1970s, replaces the bun with large leaves of lettuce; while the "Flying Dutchman" is a 2x2 with no bun, no vegetables, and no spread. Unless a variation adds meat or cheese, the price is the same as a regular menu item.
Other secret menu items include:
- Grilled Cheese - "Two slices of melted American cheese, hand-leafed lettuce, tomato, spread, with or without onions on a freshly baked bun."
- Veggie Burger - A sandwich containing only vegetables, without beef or cheese.
- Chopped Chilies - Chopped yellow chili peppers are added to the burger.
- Spread - packets of refrigerated "spread", similar to Thousand Island dressing.
- Hot Yellow Chili Peppers - packets of two whole yellow chili peppers. These can also be added to the burger by requesting "Chopped Chilies" (see above).
- Pickles - pickles do not come on the burger and can be added upon request.
In-N-Out's burger customization offers customers a choice of four different onion styles. Raw onion is available by the slice (standard for "with onion") or chopped. Likewise, sliced or chopped styles are also available for grilled onions. How the onions are prepared will determine their placement on the sandwich. For instance, raw sliced onions are arranged with a burger's cold ingredients, while grilled onions are placed directly on the beef patty.
In-N-Out uses the Kennebec variety of potato for its fries and prepares them on-site as opposed to purchasing them pre-made from other companies. The company's french fries are cooked in "100% pure, cholesterol-free vegetable oil."
The following variations are available off-menu:
- Fries "Light" - Decreased cooking time for a softer product.
- Fries "Light Well" - Slightly increased cooking time for a crispy outside.
- Fries "Well" - Increased cooking time for a crispier product.
- Fries "Extra-Well" - Further increased cooking time for a very crispy product.
- "Animal Fries" - Melted cheese, spread, and grilled onions.
- Cheese fries - Fries with cheese.
The company offers lemonade, iced tea, coffee, three flavors of milk shakes (chocolate, vanilla, and strawberry), and soda. Unlike most fast food companies, In-N-Out serves soda from two different companies. It serves Coca-Cola Classic, Diet Coke, and Barq's Famous Olde Tyme Root Beer —except in Utah, where it serves caffeine-free Barq's root beer — from the Coca-Cola Company, and 7 Up and Dr Pepper from the Dr Pepper Snapple Group. The company advertises that its milkshakes are made with "100% real ice cream." 
- Root beer floats
- "Lemon-Up" — a mixture of lemonade and 7 Up.
- Lemonade/Tea mix — known as an "Arnold Palmer", a mixture of iced tea and lemonade.
- Choco-Vanilla Swirl shake — a mixture of vanilla and chocolate flavors
- Neapolitan shake — a mixture of vanilla, chocolate, and strawberry flavors
- "Large" shake and "Extra Large" shake. Large is a medium drink cup, Extra Large is a Large Drink Cup.
- Perman, Stacy (2009). In-N-Out Burger: A Behind-the-Counter Look at the Fast-Food Chain That Breaks All the Rules. New York: Harper Collins Publishers. ISBN 978-0-06-134671-2.
- Tom McNichol (2002-08-14). "The Secret Behind A Burger Cult". The New York Times. p. Late Edition - Final, Section F, Page 1, Column 1. Retrieved 2007-07-21. "Over the years, this trend has evolved into what's become known as the Secret Menu -- a list of popular burger variations that do not appear on the menu but are passed along by word of mouth."
- "Menu". IN-N-OUT Burger.
- "In-N-Out 100x100". @whatupwilly!.
- Daisy Nguyen (2004-03-26). "Bunless burgers old hat at In-N-Out". The Oakland Tribune. Retrieved 2007-06-17. "In fact, it was customers who gave it the name protein style," said Carl Van Fleet, the company's vice president of planning. "They also created it, in a sense, when they began requesting it in the early 1970s..."
- John Marcotte (2005-02-25). "In-N-Out’s secret menu". Badmouth. Retrieved 2010-12-20.
- John Marcotte (2005-02-24). "In-N-Out’s secret menu". Badmouth. Retrieved 2013-01-05.
- J. Kenji López-Alt (2011-03-11). "The Ultimate In-N-Out Secret Menu (and Super Secret Menu!) Survival Guide". Serious Eats. Retrieved 2013-01-05.
- "Esther Snyder -- co-founder of In-N-Out Burger restaurants". San Francisco Chronicle. Retrieved 2012-11-09.
- "MENU AND FOOD QUALITY". IN-N-OUT Burger. Retrieved 2012-09-12.
- "MENU AND FOOD QUALITY". IN-N-OUT Burger. Retrieved 2012-09-12.