SHE. – What are the differences between flat oysters and hollowed oysters?
Hugo Boutrais. – The flat oyster is an oyster endemic to France with the characteristic of being flatter as well as rounder in its shape. In France, it is associated with the Latin name Ostrea edulis. This oyster became rare in the 1960s, following significant mortality due to an oyster-specific disease. It is still produced and cultivated in France, but in smaller quantities. 95% of the oysters grown and marketed in France are hollowed oysters. The more elongated shape is hollow below and the shell is flat above. The Pacific oyster belongs to the species Magallana gigas, which was previously called Crassostrea gigas. It was introduced in 1960 and imported from Japan, following the flat oyster problem. Between Japan and France there are many climatic similarities, which is why this oyster does very well in France.
As for its taste, the flavor of the flat oyster is quite delicate, with an acidic side, sometimes even a little stony. There is a highly iodized garnish for the fine oysters and a sweeter, nuttier garnish for the special ones.
The flat oyster requires a slightly different opening method. We open it at the hinge, at the bottom, when we open the hollowed-out oyster on the side.
SHE. – What is your advice for opening an oyster without hurting yourself?
HB – It takes a little help to learn, with some fundamentals. First of all, you have to hold the knife well: let very little of the blade protrude from the knife holder. People tend to grab the knife by the handle and try to open the oyster by applying pressure. That’s when you get hurt, when you slip. What you should avoid at all costs is keeping the blade at bay. Instead, you should take the blade in your hand and hold it tightly, allowing only a centimeter of the blade to protrude from your grip. Obviously, you can use a protective glove. There are mesh gloves, which are effective. Otherwise, you can use a thick cloth to protect the hand holding the oyster. Beginners hurt the hand holding the oyster. Then, when you become an expert, you hurt your other hand. It is the other hand that slides over the oyster. To open, you must insert the knife two thirds of the way. We have the “butt” of the oyster facing us and identify the place where the muscle that holds the two shells is. To identify it, it is at the level of two thirds of the length of the shell. Generally this is where we try to insert the blade between the two valves. We scrape to cut this muscle that forms the joint of the oyster. What is also essential is to check that there are no shell fragments left in the oyster. Very important, there is a part of the oyster that often stays stuck to the upper part, which is flat. The best thing is that this veil remains “solidarity” with the entire shell. This is what allows us to preserve the shell and present it in the best possible way.
SHE. – Should we throw the first water?
HB – The first water is always quite salty and loaded with minerals. It is not very tasty, I recommend throwing it away. The oyster can replenish its water up to seven times and the second water will be tastier.
SHE. – What is this water for?
HB – An oyster filters water, naturally. She lives in this sea water and always has this reserve of water, her reserve of life. As long as it is full of water we will say that it is alive. If it ever loses this water, it dries up and, little by little, dies. I like to say that the oyster has 7 lives like a cat that rests on the 7 waters that it can remake (on average).
SHE. – How do you know if an oyster is fresh?
HB – When you open it, an oyster weighs quite a bit. We feel the weight of its water. It is neither trivial nor contemptible. A very fresh oyster is an oyster that will have lost its water without replacing it. If it is closed it sounds hollow. When we package the oysters, we put them together. We listen. If the sound is hollow, it means the oyster is dry. It’s not necessarily dead, but it has lost a lot of water. You can check it by touching it. We open it and then touch the gills a little. If she shrinks, she is still alive. It is a seafood that is eaten alive. If it’s still moving, we can still eat it. The first thing to check is the presence of water. If it’s already open, that also means it’s dead. If it’s too easy to open, it’s not good. It doesn’t smell good, in the first figurative sense of the word. A fresh oyster smells like oysters. An oyster that is not fresh smells very bad, there is no doubt about that. When you don’t know this smell, it is actually the smell you can smell when you leave fish offal in the trash.
If it’s already open, if it yawns, you should try closing it to see if it holds. If we see that it maintains its closure, it means that it still has strength and is edible.
SHE. – How to ensure that oysters stay fresh after purchase?
HB – The ideal temperature is between 4 and 10°C. The bottom of the refrigerator, where you keep vegetables, is ideal. We do not always have another option, but it is best to avoid dry places. It is better to be wet and cold. How to reproduce wet cold instead of dry cold? The refrigerator is dry and cold. To have a wet cold, we keep the oysters flat, hollow side down, because they need to retain water. When it gets tired, the oyster opens a little, and if it is crooked, the water leaks out. While if she is tired, but upright, the water stays inside and she survives more easily. Optionally, you can cover the oysters with a damp cloth to avoid this excessive exchange between the dry side of the refrigerator and the wet side of the shell, this prevents thermal shock and desiccation. Shelf life is on average 7 to 10 days. There are actually no days where you can keep and eat them while they are alive.
SHE. – Is there an obligation to buy these oysters at the last minute?
HB – No, on the contrary, we can do it in advance. 5-6 days notice is fine, even 10 days notice for special offers. In the case of fine and classic oysters, it is a little more risky because they are fragile. By the way, that’s why they are cheaper. But I would say 5 days in advance.
SHE. – At what temperature should oysters be served?
HB – If you store them cold, it is good to leave them at room temperature for 1 or 2 hours so that they warm up again. If an oyster is served at 10-12°C, this is not a problem. Otherwise. It will be tastier, when you eat it cold it usually tastes a little salty. The cold amplifies the sensation of salt.