Seafood boil is the generic term for any number of different kinds of social events in which shellfish is the central element. Regional variations dictate the kinds of seafood, the accompaniments and side dishes, and the preparation techniques (boiling, steaming, baking, or raw). In some cases, a boil may be sponsored by a community organization as a fund-raiser or a mixer. In this way, they are like a fish fry, barbecue, or church potluck supper. But boils are also held by individuals for their friends and family for weekend get-togethers and on the summer holidays of Memorial Day and the Fourth of July. There are also companies that can cater a boil for large and small events. While boils and bakes are traditionally associated with coastal regions of the United States, there are notable exceptions. For example, the Fiesta Oyster Bake  (San Antonio) began in 1916 as an alumni fund raiser for St. Mary's University. It is now attended by over 70,000 people during its two day run and is a major music and cultural event in the city.
Shrimp, crab, and crawfish boils can be found across southern Louisiana. But it is the crawfish boil that is most closely associated with the region. The Breaux Bridge Crawfish Festival has been named one of the top 10 food events by USA Today and is a showcase for Cajun music and culture. Major crawfish boils are held by churches and other organizations as fundraisers throughout the spring. Tulane University holds an annual "Crawfest" in April, and the University of New Orleans holds an annual crawfish boil for all students at the end of the spring semester (Students unwinding on Crawfish and Unprecedented Fun--SUCAUF). Smaller events can be found in backyards and parks throughout April, May, and June. Locals traditionally eat crawfish, as well as crabs, without tools such as shell crackers or picks.
One reason for the popularity of crawfish may be price. During the height of the season (late spring) the price may be less than a $1.50/pound retail for live crawfish (2006) with crawfish prices currently being around $.99/pound. Shrimp and crab are higher valued cash crops, and can be a less affordable option for larger groups.
A boil is usually done in a large pot (60 to 80 quarts) fitted with a strainer and heated by propane. However, some traditionalists see no need for a strainer and make use of a net or a wire mesh scoop. Seasonings include crab boil packets, cayenne pepper, hot sauce, salt, lemons, and bay leaf. Ears of corn, new potatoes, onions, and heads of garlic are usually included in shrimp and crawfish boils. Some people will add smoked sausage links and/or mushrooms. When cooking crawfish there is a debate over whether or not the crawfish must first be purged by covering them with clear water and a generous amount of salt for a few minutes. Advocates argue that this forces the crawfish to rid their bodies of impurities. Others argue that it doesn't work and is an unnecessary step. A "Boil Master" is in charge of making sure the ingredients go into the pot in the proper sequence and controls the timing of the steps. There are is no right or wrong when seasoning a crawfish boil and many experienced boilers simply go by feel although there are some guidelines to follow and a great deal of opinions on how a boiled crawfish should be seasoned.  Many recipes call for a short boil followed by a period of soaking with the heat turned off. The contents of the pot are removed, drained, and then dumped onto a newspaper covered table. Sometimes, crawfish may be dumped into the traditional watercraft in which crawfishermen have historically used to traverse the bayous and swamps; a pirogue. Bottles of hot sauce, lemons and melted butter are usually available, along with cocktail sauce at a shrimp boil. Some families like to use Italian salad dressing or ketchup, or a mixture of both.
Howard Mitcham and his Guild of Chimney Sweepers (named in honor of a dinner that Charles Lamb hosted for the London sweeps) hosted a shrimp boil every year for French Quarter bohemians during the 1950s and 60s. He notes, "At our last big party we boiled 400 pounds of shrimp and 400 fat crabs for 200 guests and we drank eight thirty-gallon kegs of beer. For music we had Kid Thomas and his Algeiers Stompers, the famous old gut-bucket jazz group from Preservation Hall, and the Olympia Funeral Marching Band". The Chimney Sweepers technique was to use new thirty-gallon galvanized garbage cans, filled one third full of water and brought to a boil with seasonings. The shrimp were divided into 25 pound batches and stuffed into new pillow cases and tied off. Twenty-five pounds of shrimp took about 25 minutes to cook. One batch came out and the next went in.
There are two kinds of social gatherings in South Carolina that revolve around shellfish. One is very much like a Louisiana boil, usually involving shrimp, corn on the cob, sausage, and red potatoes and is considered part of Lowcountry cuisine. Known variously as Frogmore Stew, Beaufort Stew, a Beaufort boil, a Lowcountry boil, or a tidewater boil, they tend be a bit milder than their Louisiana Cajun and Creole cousins. For example, it is not unusual for a Lowcountry recipe to call for a mixture of hot and mild crab boil seasonings, e.g., Zatarain's and Old Bay, whereas a Cajun recipe may start with crab boil packets and add large amounts of cayenne pepper and hot sauce. While shrimp are most often used, crabs and or crawfish may be included if available. This is also a bit different from a Louisiana boil, which usually involves just one kind of shellfish.
This hearty one-pot dish is always a crowd-pleaser. When Frogmore Stew was first cooked in the 1960s, Frogmore was a little hamlet on St. Helena Island, near Beaufort, South Carolina. In the 1980s, however, the postal service abolished the name Frogmore. That changed the name of the popular dish to Lowcountry Boil or Beaufort Stew-except, of course, among the proud (and peeved) residents of Frogmore.
Richard Gay, whose family owns Gay Fish Company on St. Helena, created the dish in the early sixties. "I was on weekend duty in the National Guard," he says, "and I'd sometimes get a lot of shrimp, put it in a pot with sausage and corn, and boil it up. Within an hour, we could have a complete meal for 100 people. The boys teased me that since I was from Frogmore, we'd name it Frogmore Stew. We put out copies of the recipe at the seafood market at the dock and began selling the other ingredients as well."
The most well attended function to feature Frogmore Stew occurs in July at the 10 day Beaufort Water Festival (in the 54 years of the festival it has grown to be the largest totally volunteer run festival on the south eastern coast), the event feeds 2400, the recipe includes 1200 lbs of shrimp, 2400 ears of corn, 600 lbs of sausage, 72oz of seafood seasoning and is served with 350 lbs of coleslaw, 250 gal of iced tea, 2400 rolls and 90 watermelons.
The other kind of event is the Oyster Roast. Sheet metal or a fine mesh grill is placed over hot coals. Oysters are piled onto the grill (after having the mud washed off their shells). Wet burlap sacks are draped over the shells and the oysters are half grilled and half steamed. A shovel is used to scoop them onto nearby tables (plywood sheets on sawhorses works as well as anything). The shells have popped open (and are still hot), but the oysters are attached and just need a little coaxing to come free. This is particularly popular in the winter (the 'R' months) when the oysters are good and a hot fire keeps the coastal chill at bay.
Both of these events are often large social functions in which a neighborhood, family, or friends gather for fellowship. Music, drinking, and dancing, especially the Carolina shag, are also common at these events. The most famous example of such a function takes place in Columbia, South Carolina, in early December, on King Street.
The Chesapeake Bay is the largest estuary system in North America and provides an abundance of blue crab, Chincoteague oysters, and clams. It is located at the boundary between the South and Mid-Atlantic states and shares culinary traditions with both. Crab houses (also known as Crab shacks) serve freshly steamed crabs and are found along both shores of the bay.
The Maryland Crab Boil (known as a Crab Feast– "Crab Boil" is generally not a phrase used in Maryland) is a popular event for small groups of friends. Despite the name, the cooking technique is actually steaming. Crab pots have a raised bottom that keeps a fitted basket above the liquid. A couple of inches of beer (or water) mixed with vinegar is brought to a boil. The crabs are placed in the basket and sprinkled liberally with a seasoning mix (usually Old Bay), and then placed in the steamer. Twenty minutes later the bright red crabs are pulled up and turned out onto trays or platters. Tables are covered with layers of brown paper and wooden mallets and serrated knives are made available for cracking claws and picking out meat. Typical side dishes are cole slaw and corn on the cob.
In New England, a clam bake is traditionally done on a beach. A pit is dug in the sand and lined with stones. A fire is built on top of the stones from driftwood. Once the fire dies down, seafood is placed on the stones and covered with seaweed and a canvas tarp. The residual heat from the stones along with steam from the moisture of the seaweed combines to cook the food. While lobster is often featured at clam bakes, some authors suggest that in practice, lobster will not be fully cooked by the time the stones have lost most of their heat.
An alternative to the labor-intensive bake is the New England Clam Boil. Like other regions, corn, potatoes, and sausage are popular additions. Recipes from the region suggest that little or no seasonings are added. Beer is often used as the boiling liquid.
The events listed above are generally regarded as the definitive versions. But variations exist around the country.
This variation on the Louisiana boil features shrimp and crawfish as well as Dungeness crabs (not a Louisiana item). The boil seasonings are also quite typical of the Louisiana style, but with the inclusion of oranges.
The Charente-Maritime département of France on the Bay of Biscay, is noted for the abundance of mussels. The Éclade des Moules is a bake often held on the beaches outside of La Rochelle. The mussels are arranged in concentric circles on a plank so that the hinged part of the shell is facing up. Pine needles are mounded on top to a depth of a foot or so and set afire. The needles burn down quickly, producing a rich resinous smoke. Two or three minutes after the fire goes out, the ashes are swept away and the mussels are eaten directly from the shell along with country bread, butter, and white wine.