How Frozen Oysters on the Half Shell Have Changed the Way Restaurants Cook Oysters

Introduction: What is a Frozen Oyster?

Frozen oysters are oysters that have been preserved by killing and then freezing them, after which they are sealed in an airtight container. This process prevents the loss of liquid from the oyster as it freezes and thaws. Fresh, whole cans of frozen oysters can be consumed over a period of time (even just a few weeks), or cooked to be “opened” for immediate consumption. Frozen oysters have been used by restaurateurs in Asia, Europe and the United States since the mid 1960’s. The storage of a large number of oysters for a later time, without the use of ice, saves both space and energy. Such huge quantities are also better able to be handled and stored in refrigerated warehouses. Many small commercial fisheries have opened up in order to take advantage of this new type of food preservation technology.
Today, frozen oyster dishes can be found in restaurants almost anywhere that seafood is served. They are a common dish at formal dinner parties and, in recent years, have found their way into upscale restaurants that cater to an older clientele. Frozen oysters are also sold in supermarkets as a readily prepared item at a reasonable price.

frozen oysters on the half shell
frozen oysters on the half shell

The History of Frozen Oysters

The frozen oyster business was born as a response to the post-World War II boom in American travel and tourism in Europe. The reason that it was invented is because the oysters were dying out due to over fishing and pollution. Oysters were so precious to America’s economy (it is estimated that $1.5 billion a year was spent on oysters in the mid 1950s) that it was in danger of extinction. So, to preserve them, they were brought to Belgium and cooked on site. The oysters could then be placed into plastic bags and shipped back to the United States where they would be frozen. The frozen oysters were known by a variety of names, all ending in “trestave.” The most popular was “Frühstuck” (German for “fresh”).
It wasn’t until 1946 that the first oyster industry on the East Coast was established. In fact, up to that point, most oysters were harvested far out at sea by boats. The freezing process would take three to five days and is where much of the expense came from: frozen oysters cost six times more than fresh ‘treestaves.
The method for freezing the oysters was devised by a Belgian named Jean-Baptiste Thys. He would first gather oysters in several barrels inside of a shack, where he would “drain” them with an electric current to kill anything that they had. He then put the shells into a freezer that was kept at below freezing temperatures to slow down their growth, and also to stop any mollusks from moving out of their shells. He would then return to the shack, with a large masonry mortar, and begin crushing the oysters against a stone block with a pestle. He would then return to the freezer and pour them straight into the bags of frozen oysters.

frozen oysters on the half shell
frozen oysters on the half shell

What to Expect from a Traditional Overnight Saltwater Brine

A frozen oyster is not a “true” oyster. It will have a very different texture and flavor than a live, non-frozen oyster. In the most traditional methods, the oysters are placed into bags of brine and packed under vacuum pressure. The vacuum creates an extremely low pressure inside the bag, allowing oxygen to enter the oyster. This oxygen is what dissolves away the metals that turn up in high profile headlines about poisoning every month (and in some cases every week). As part of the brine, a pinch of sugar and salt is added to the bag to prevent spoilage and allow the oysters to be shipped out. Once the vacuum is released and the oysters are removed from their packaging, they are placed into a bath of water that is below freezing. Now, add the oysters to coolers with ice packs until they are frozen solid.
So how long do you leave them in the brine? A few days maximum for a large batch of oysters, more time for smaller portions. A 24-hour period can be expected for every gallon (4 L) of ice, up to 48 hours if necessary.

frozen oysters on the half shell
frozen oysters on the half shell

Thawing Method of Frozen Oysters on the Half Shell

If you choose to eat a frozen oyster on the half shell, you can thaw it at room temperature in the brine that it was packed in. This is a much more time consuming process that involves cooking the oysters over an open flame and watching them carefully. The contents will be cooked before they are cooled and put into an airtight bag. They will not have to be cooked again. The oysters are placed into a metal pan, topped with a metal dome, and placed on the grill to begin thawing. The heat from the fire is used to thaw the oyster, which takes about four minutes.
The oyster is then carefully picked up and placed into an airtight container. It may be wrapped in plastic or paper before this process and placed into the refrigerator to await consumption. After the oyster has thawed, it can be eaten either on the half shell or opened up and eaten with a fork.
Frozen oysters are more susceptible to bacteria than fresh ones, so it is best to avoid eating them for at least 48 hours after you have purchased them. A frozen oyster will be much fresher if it was frozen within an hour of being harvested.
The brine that the oysters were packed in when they were put into the freezer will be all that they require to thaw them, since they are already cooked when they are frozen. This means that you have no additional work to do other than carefully watching the oysters. The time involved in thawing out a frozen oyster on the half shell is about 4 minutes, compared to 30 minutes for a fresh one.
There are several brands of frozen oysters on the market. Your best bet will be to check with your local supermarket or regional fish distributor to find out which brand has the freshest oysters that are available. If you cannot find the brand advertised, then you may want to look for another brand.

frozen oysters on the half shell
frozen oysters on the half shell

Shucking Process of Frozen Oysters on the Half Shell in Commercial Settings Today

The oyster can be eaten as is, or opened with a knife, fork and spoon. An oyster shucker will then place the oysters into an ice chest full of ice. This helps keep the temperature cool while they are served. Frozen oysters can be kept in the ice chest for up to six hours before they should be put in the refrigerator and served. After being shucked and placed in the ice chest, the oysters should be blended with a mortar and pestle. This blends a little of the seawater into the oyster meat which creates a unique texture. The oysters can then be served as is, or can be further crushed by hand.
The shucking process requires that both hands be used instead of one, which allows two people to share in the preparation of fresh oysters. The shucking process also requires the use of a knife, fork and spoon. The first step in the shucking process is to remove the oyster’s top shell. This top shell must be removed before the oyster can be served because the top shell will block any additional flavors from entering into the oyster’s flesh. To remove this top shell, a small knife or oyster cracker should be used to open it up. Once this is done, there are two shells: one that sits above the meat and one that sits below it. The body of the oyster should then be cracked out of the shell beneath it with a knife. Once this is done, the top shell can be removed and the oyster meat can then be consumed or served on a plate.

frozen oysters on the half shell
frozen oysters on the half shell