#What is the Brown Stuff in Oysters? A Closer Look at This Common Concern
Oysters are one of the most popular shellfish around Their briny flavor and soft, succulent texture make them a delicacy unlike any other However, when preparing oysters at home, you may notice some brown or green gunk inside the shells. The question is – what is this mysterious brown stuff in oysters?
As an oyster lover myself, I used to wonder about this too. That’s why I decided to do some research to uncover the truth about the brown slime that can sometimes accompany our favorite bivalves. Keep reading to learn what’s really inside those shells and whether it’s safe to eat.
##What is the Brown Material Inside Oysters?
The brown substance frequently found in oysters is not feces as some assume. It is actually a combination of algae and sediment that the oyster has filtered from the water and collected as food. Oysters are filter feeders which means they pump large amounts of water over their gills to trap tiny plankton and algae for nourishment.
As the oyster feeds, some of this nutritious material gets caught in its shell along with dirt and debris filtered from the water. This mixture of food and sediment accumulates in the shell, taking on a brown or green tint.
The color comes from phytoplankton, which are tiny marine algae. Phytoplankton contain chlorophyll and carotenoid pigments, which lend a green or brown hue to the material.
##Is it Safe to Eat the Brown Stuff in Oysters?
The good news is that the brown sludge inside oysters is totally safe and natural to eat. Since it’s comprised of the same phytoplankton and algae that oysters consume for food, many consider it a delicacy.
The phytoplankton boast an abundance of nutrients, such as:
- Protein
- Vitamins A, C, E
- Antioxidants
- Healthy fats like omega-3s
- Minerals like iodine and iron
Some oyster aficionados even claim that oysters with the brown substance inside taste sweeter and more flavorful. The phytoplankton provide a boost of extra marine essence.
So rest assured that slurping down the brown algae along with the oyster meat is not only safe, but good for you!
##Does the Brown Material Mean the Oyster has Gone Bad?
Nope! The brown slime does not indicate spoilage or contamination. As long as the oyster still looks, smells, and tastes fresh when you shuck it open, the presence of algae does not make it inedible.
Signs that an oyster has gone bad include:
- Foul, sulfur-like smell
- Milky colored liquid in the shell
- Dry, shriveled up meat
- Gaping shell that won’t close
As long as none of these warning signs are present, you can feel comfortable eating oysters with phytoplankton buildup inside. It’s a natural byproduct of their filter feeding behavior.
##When Does the Brown Gunk Appear in Oysters?
The algae accumulation occurs more frequently during the active growing times for phytoplankton. In most areas, this is typically spring through fall when water temperatures are warmer.
In the colder winter months, oysters feed less actively, so they take in less phytoplankton. Their shells stay cleaner as a result.
The brown slime is also more common in oysters from the intertidal zone closer to shore. These oysters tend to feed on more sediment and build up larger amounts of algal material.
Oysters further offshore or deeper underwater filter clearer water and collect less debris. So they often don’t have as much brown gunk.
##Tips for Cleaning the Brown Stuff Out of Oysters
If the sight of the brown algae puts you off from eating oysters, know that you can easily clean it out before serving. Here are some tips:
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Place oysters in a colander and rinse under cold running water. Gently rub shells with fingertips or a brush to remove algal buildup.
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Soak oysters in cold water with lemon juice or vinegar for 5-10 minutes. The acid helps dissolve the gunk.
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Place oyster shells on a bed of crushed ice for 30 minutes. The ice chill makes the algae shrink and detach from the shell.
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Use a sharp, flat knife to carefully scrape out the brown substance after shucking the oyster meat off.
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For cooked oysters, briefly blanch or steam them before shucking. Blanching helps loosen the algal film from the shells.
##Conclusion
Though it may look unappetizing, the greenish-brown ooze inside oysters is actually a good sign. It means you’re getting a boost of nutritious phytoplankton with your delicious oyster meat.
As long as your bivalves smell fresh and look healthy, don’t be afraid to slurp up every last drop. The algae only adds a concentrated dose of briny oyster essence.
However, if the sight is off-putting, a quick rinse or scrub of the shells can remove the majority of the gunk. Then you can enjoy your oysters pristine!
So next time you pry open an oyster and spot some brown, think of it as an edible badge of honor. Your oyster has been hard at work filtering the freshest food from the sea, just for you!
Is it safe to eat oysters during months without the letter R?
Yes, it absolutely is safe to eat raw oysters during months without the letter “r” (e. g. , May, June, July, August). If you’re in Australia and New Zealand, you’re probably thinking that’s when oysters are best!!!.
So where did this idea come from?
Most oyster experts say that this saying comes from a time before modern oyster farming technology, when oysters could only be raised from oysters found in the wild. In the Northern hemisphere, oysters spent much of their energy reproducing during the r-less, summer months. During that time, it was best for harvesters to leave the the oysters alone to reseed the beds.
Some articles, like this New York Times piece, credits William Butler, an English physician to King James I, with stating, “The oyster is unseasonable and unwholesome in all months that have not the letter R in their name,” in 1599. But according to a 2017 New York Times article, the quote is also credited to Henry Buttes in an 1599 English cookbook, Dyets Drie Dinner. Luckily for you and me, Nigel Moore, an intrepid oyster enthusiast / history buff, wrote an in-depth blog post about this whole thing.
In light of this, you can see that the R-month rule is no longer relevant to the oyster business today. Here are the two R rules that I follow: Refrigeration and Regulation.
Refrigeration: Don’t eat oysters that haven’t been kept cold. The FDA says that live shellfish should be kept below 40 degrees F. This is especially important in the summer when there is a higher chance of vibrio growing in the water.
Regulation: Don’t eat random oysters that you find on the beach, unless if it’s from a designated recreational shellfish harvest zone. Also, don’t buy oysters from people or places without proper documentation. To be extra conservative, first check to see if the company’s name is listed on the FDA’s Interstate Certified Shellfish Shippers List.
What do oysters eat?
Oysters eat phytoplankton or small bits of algae suspended in the water. They are filter feeders, which means that they obtain their food by filtering water in and over their gills. Adult Virginica oysters can filter up to 50 gallons of water per day. Sometimes they’re referred to as bottom feeders or detritivores, but don’t turn your nose up at them because of that.
To demonstrate their fascinating ability, here is a time-lapse of oysters in filtering action.
Now you may be wondering… if oysters eat anything that swims by and they’re in water full of “nutrients,” then aren’t we all just eating garbage?
The reason you still can’t order oysters from New York Harbor is because of this. This is also the main reason why we need to protect our waters from getting even more dirty. In New York Harbor and other places in the U.S., the Clean Water Act has really helped make the water better. S. , but we’ve still got a long way to go.
Oysters are voracious vegetarians, but fairly picky about what they nosh on. Despite the absence of a brain, oysters “know” what they can and cannot digest. Bob Rheault, Executive Director of the East Coast Shellfish Growers Association, says, “Even when they’re as small as dust specs, they do this.” As much as 90% of the time, the oyster can sort identically sized algae particles (like Isochrysis and Chlorella) even when they are mixed with a thick silt soup. The isochrysis goes into the gut, and the chlorella and silt go into the fake poop, which turns it bright green! I have done this with radiotracers and the degree of efficiency is remarkable. This is one reason the American oyster is so flexible and can live in waters with a lot of silt while many other animals struggle and die from suffocation from gills that get clogged. ”.
What is the green stuff inside an oyster?
FAQ
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