Winter Effects On Oyster Quality

From February to April, we tend to see quality issues on certain varieties of oysters. It’s something that happens each year, so we put together this FAQ to help address your winter concerns.

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What are oysters doing during winter?

When we’re asked to think of animals that hibernate, bears, bats and other small mammals usually come to mind. But did you know, oysters also “hibernate” during the winter? Contrary to children’s books and fairy tales, animals in hibernation are not sleeping. Hibernation is a form of dormancy in which animals conserve energy to survive harsh environmental conditions. Oysters go dormant during winter because water temperatures can stay below freezing for months. Evolution has also taught them that there is no food in the water when everything is iced over.

How do oysters survive their winter dormancy?

To prepare for winter dormancy, oysters feed like crazy during the fall to build up glycogen, their sugar stores — which is why they are so sweet in autumn. When the water temperatures drop to 40° F, it signals the oyster to stop metabolizing and go dormant. The oyster will barely pump during this time and survive on its glycogen to get through the winter. When the waters warm up and food is back in the water, the oysters will become active again and start feeding. They will pump, filter, and eat from spring to fall until water temperatures drop again, triggering another cycle of dormancy.

oyster quality cycle_pangea.PNG

What is winter kill?

Inevitably, there are oysters that will die during winter dormancy. This phenomenon is called winter kill. Oysters run out of glycogen to stay alive or they are too weak to withstand the harsh conditions. The worst part is, some of these oysters die remaining shut. This makes them difficult to detect even when harvesters go through them by hand.

What are some signs of winter kill?

Because some oysters die shut, they cannot be detected until they are shaken up or shucked open to reveal dry, shriveled, smelly meats. Dormant oysters are weaker and have difficulty healing themselves, so any chipping during harvest, culling, packing, or transit can lead to liquor loss.

Once we hit late February and into March, we are basically asking the oysters to do the most impossible journey possible. Out of the water, through the packing house and shipped across the [Canadian] border by refrigerated truck. If at any point in that journey, the oyster [attempts] to feed or gets jostled in a harsh manner that loosens the abductor muscle, the oyster will spill some of its precious liquor and there’s no opportunity to replace the liquor… The oyster will not likely open again until spring when he’s either bone dry from survival or is sufficiently convinced that the water temperatures are steady again.
— Jacob Dockendorff, PEI Producer

Why does winter kill affect certain varieties more than others?

If you are a Pangea Shellfish customer, you will notice that certain oyster varieties are unavailable from March to May like wild-harvested Malpeques. These are the months when winter kill is most apparent, and Canadian supply is a great example.

Canadian waters get colder earlier in the year than locations down south. This also means the oysters enter dormancy earlier than its southern brethren. If a Canadian oyster enters dormancy in early November, it may not start feeding again until May when waters warm. It basically needs to survive on its glycogen that whole time! It’s impossible to ask the oysters to be in tip-top shape from March through May when they have not eaten for six to seven months.

You will also see signs of winter kill in New England oysters as we approach March, but it’s not as noticeable because their dormancy period is shorter. New England oysters are likely feeding until the end of November and start feeding again in late March. They have to survive about four months compared to the six months Canadian oysters endure.

Average Water temperatures in Summerside, PEI.  Water temps drop to 40F by early november and do not warm back up until late May. Oysters are dormant that entire period.  Source: NOAA

Average Water temperatures in Summerside, PEI. Water temps drop to 40F by early november and do not warm back up until late May. Oysters are dormant that entire period. Source: NOAA

Average Water temperatures in Barnstable, MA.  New England water temps do not drop to 40F until late November / December, which allows the oysters to feed longer and remain in dormancy for a shorter amount of time compared to Canadian oysters.  Source: NOAA

Average Water temperatures in Barnstable, MA. New England water temps do not drop to 40F until late November / December, which allows the oysters to feed longer and remain in dormancy for a shorter amount of time compared to Canadian oysters. Source: NOAA

Which varieties are less susceptible to winter kill?

Winter kill is less of an issue for southern varieties because of warmer water conditions, but generally, farmed oysters have a better chance of survival than wild oysters. Growers make sure their oysters have the best access to food throughout the year and condition them to have stronger abductor muscles. Farms also have different wintering and culling methods to tackle winter kill and limit its effects on product quality. So, despite Canadian oysters being more susceptible, many of the cultured Canadian varieties look nice throughout the season.

When will quality improve?

When the oysters finally start pumping and feeding again, it will take a couple of weeks for their quality to improve as they replenish themselves. Timing will vary by area because water temperatures differ by location, but we will see most varieties in better shape by late May.

Is there anything I can do to limit the effects of winter kill?

Yes! Be gentle. The oysters are weak, so any tough handling will result in dry or dead oysters. Give them extra attention and protection, especially in transit.

If you encounter a smelly bag, make sure to go through the bag or box because it could just be one dead oyster responsible for the smell. Discard the dead and rinse the rest. The remaining live oysters are just fine!

If there are any issues, contact your supplier. Dead oysters can go unnoticed until shucked, so giving your supplier feedback can help them assess the situation.

Duxbury Bay, January 2019, Mike Cesarini.

Duxbury Bay, January 2019, Mike Cesarini.

Special thanks to our Canadian producers for contributing to this piece.

Have a winter quality question not listed here? Ask it in the comments section below.

Outlook on Oysters 2017

Outlook on Oysters 2017

This year was a roller coaster of events. We had a mild winter which alleviated some stress from ice outs of years past yet we were more susceptible to algal blooms, recalls and closures from the summer’s drought. We saw more oyster bars popping up all over the country as the Nation’s appetite for bivalves is becoming more insatiable. Here is the start of what may be in store for 2017. 

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Introducing the Pangea Oyster Flavor Wheel


Why we created a tasting wheel

Sometimes it's difficult to describe or even distinguish the taste of one oyster from another, so we wanted to create a tool to help people reference what they are tasting. Like wine, oysters, are greatly influenced by their environments, so they express a lot of that "merroir" through their flavor. There are many flavor wheels in the specialty foods industry (e.g. wine, coffee, and cheese). Some are definitely more complicated than others, but they all try to do one thing, which is to help the taster explain or map nuances in flavor and aroma.

What makes our wheel different

When we created this wheel, we wanted to make sure it was comprehensive, but also approachable. We didn't want a mash of words simply in wheel form. Instead, the wheel is meant to be a map that guides the tasting experience from start to finish.

We believe that texture is a huge component in describing an oyster's flavor profile and have dedicated a good portion of the wheel to that category. In other wheels, smells before consumption have been emphasized, but based on our experience, it's hard to detect more than an oyster's refreshing ocean smell (unless it's a foul oyster, in which case you shouldn't eat it). Texture, or mouthfeel, can range widely among varieties due to the oyster's species or growout method. Therefore, we wanted our wheel to have a sufficient number of descriptors in this area. 

How we define taste, texture, and finish

Taste can only be five things: sweet, salty, bitter, sour, and umami -- the "protein" taste. Our perception tells us we can taste more than this, but if you were to plug your nose while eating, you would only be able to detect these five things. It is only when we open up our nose, we are finally able to experience the changes in our mouth, also known as the aroma. We can tell the texture of what we are eating through chewing. Chewing creates friction and heat, which intensifies the aromas that are being experienced. When the bite is finally swallowed, some aromas may linger for some time or dissipate slowly, rounding out what we call the finish.

How we chose the vocabulary

With Bekah's skills as a chef and plenty of research, we went through a lot of oysters. We noted different tastes from our own oysters; we looked through Oysterology® information from our vendors; we looked through our weekly interoffice tasting notes; there was a lot of online research; and we even shared it with experts from other specialty foods industries. In summary, the words were pulled from many resources to create a succinct and descriptive wheel. This is the first version of the wheel, so as we learn and taste more, the wheel and its vocabulary will continue to evolve.

How to use the wheel

Start with the taste section. Make sure to note the oyster's salt content by using a brine scale of 0 to 5 (0 being no salt; 5 being full ocean salinity). Follow the wheel clockwise to note its texture and finish. An oyster may have multiple attributes in each section, so make sure you pay attention!

If you encounter an unpleasant oyster, faults are built into the wheel. The wheel does not explicitly call out faults because it is subjective, so we include it in the wheel to let the taster to determine for herself.

Tasting Tips and Suggestions

When you do get to your tasting, consider the suggestions below to ensure a complete flavor experience:

  • Do not discard the oyster's liquor. We see many oyster eaters who do this, but if you lose the oyster's brine, it will be hard to identify its salt content!
  • Chew the oyster 3 to 4 times. If you throw it back like an oyster shooter, you will completely miss evaluating its texture and much of its aromatic finish.
  • Have a palate cleanser between oysters. Water is always a good option, but alcoholic beverages or crackers work well too.

As we mentioned, this is a work in progress, and we will continue to update this as we taste and learn. Please contact us if you have suggestions or feedback for making this version more effective. We would love to hear your experiences with using the wheel or any questions navigating it. We're really excited to share this with you, and we hope you find it useful the next time you're slurping one back!


The Culling Process: Oyster Grades and Sizes

Culling, sorting oysters by shape and size, is an important step in getting oysters to market. Restaurants prefer oysters that have strong shells, easy to find hinges, beautiful shapes for presentation, and of course, deep cups filled with meat. Unfortunately, not all oysters are created equal, so growers and harvesters have to sort through their stock to find these restaurant beauties. Each grower has his or her own set of rules in determining what defines the highest grade of oysters, also known as "choice" or "select" oysters. Oysters that don't meet that grade are known as "standards" and are typically sold cheaper than their prettier counterparts.

The good news is there is always a home for any grade of oyster! Despite its shell shape, an oyster still has its flavorful meat inside, so commercial grade oysters, the lowest grade of oysters, go to shucking houses to become processed as shucked oyster meats. Many chefs enjoy using in-shell oysters for oyster meats and stuffing, so standard grade oysters are a good choice because they're freshly shucked and affordable.

Standard oysters vary in size and shape

Standard oysters vary in size and shape

select oysters are more consistent and uniform in shape

select oysters are more consistent and uniform in shape

Since growers and harvesters determine their own rules and grades, there are many descriptors and terms used to describe oysters. This is most obvious when it comes to oyster sizing. Each region has their set of terms to describe shell lengths, and even within a region, there are some nuances among growers.

We put together a summary of the different sizes and grades on the right to assist with your future oyster buying. All the different terms can get confusing, so we hope this chart will make it more straightforward and clear. You can save and share the chart just by right-clicking on the image.

To learn more about culling, watch the video above as Ben discusses his process on the Standish Shore Oyster Farm.

Always ask your suppliers about your oysters, like details on size and grade, because the more you know means the better buying decisions you'll make.

Chart of Oyster Grades and Sizes

oyster grades and sizes

The Different Methods of Growing Oysters

The Different Methods of Growing Oysters

In New England, summer is the time when oyster growers are working hard on the farm to get their baby oysters ready for open waters. Summer is also the time when growers are getting the upcoming season's crop ready for sale in the fall. As we discussed in a previous post, different culturing methods can produce totally different oysters, and there are many of them! Growers choose their preferred grow-out method based on a number of factors including their geography, potential predators, town regulations, and climate. We're going to expand on the most common methods because oyster culture terminology can get confusing, but hopefully this will also shed some light on your oysters and how they are spending their summer!

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The Argument For Farmed Oysters

The Argument For Farmed Oysters

In today’s world, there seems to be a perception that farm-raised seafood is inferior to wild-caught seafood. Farmed oysters are a very sustainable choice and equally lovely compared to their wild counterparts. Don’t believe us? Read more for the proof.

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What are pea crabs and why are they in my oysters?

What are pea crabs and why are they in my oysters?

If you've ever encountered a pea crab in your life, it's very likely that you saw one while eating an oyster! These little critters live in the gills of oysters, and sometimes will come out to play when your half shell is sitting on a plate. Many chefs and diners find them unappetizing or a nuisance, especially if they're scuttling across an oyster, but since little is known about them in the culinary world, they may be misunderstood. In 1907, The New York Times published an article titled "A Rare Delicacy, Little Known" and called pea crabs "one of the sweetest and quaintest viands known to man... so generally neglected that more than 50 per cent of the people who think they know something about good eating have never tasted the dish." So what are pea crabs? And what should you do the next time you see one?

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Are oysters really aphrodisiacs or just a Valentine's Day marketing ploy?

Are oysters really aphrodisiacs or just a Valentine's Day marketing ploy?

Oysters have long had the reputation of being an aphrodisiac. They say that Casanova, the French adventurer/womanizer, used to eat fifty oysters a day. Perhaps that's what helped him get all the ladies! So does it work? Are oysters really aphrodisiacs? Or is this all a marketing ploy to generate more oyster sales during February?

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Our 2015 Outlook For Oysters

The oyster experienced a renaissance in 2014. So what's in store for 2015?

As we look back on 2014, the oyster had a great year. Oysters received so much press and attention that it even got a shout out on the home page of the New York Times, accompanied with a video appropriately titled "Oysters Make a Comeback." Entering 2015, there is no doubt that this oyster craze will continue. Numerous oyster bars are slated for 2015 openings and more consumers are having oysters for the first time. They say the best way to predict the future is to look at the past, so join us as we recap the significant oyster trends in 2014 and what it means for 2015.


1. The Emergence of Oyster Farms and Branding

There are many reasons the oyster market is booming, but one of the primary reasons is the growth of oyster farms and brands along the East Coast. According to Bob from East Coast Shellfish Growers Association, production has doubled over the last five years, and he now estimates there are over 400 niche oyster brands on the East Coast alone. "It's like wine," Bob says. "There are a ton of brands and choices, and each one is unique."

Like terroir, oysters have their merroir, and this is a huge draw for chefs. The farm-to-table movement has created an excitement around understanding where and how ingredients are sourced, and this is no exception for oysters. Private labeling and exclusive distribution of brands have allowed chefs, restaurants, and distributors to tell the oyster story that is unique to them. And consumers love it, so much so that it has sparked a market for oyster farm tourism and even an app to geolocate specific oysters.


Expect to see more farms and brands appear on the market, but also a shift towards vertical integration through exclusive distribution or private labeling as players strive to differentiate themselves and capture greater market share from loyal consumers. There are oyster farms that are already vertically integrated where the farm directly supplies its own branded restaurants (e.g. Island Creek Oysters and Matunuck Oysters) and farms who grow the same oyster with multiple names for distributors or restaurants to claim exclusive distribution rights. More farms are now marketing directly to consumers to build brand loyalty and generate demand whether by shipping product direct-to-consumer or offering consumer experiences such as tours.

2. Rise In Industry Profits Draws Shady Business

As with any industry, the potential for sales and profits will draw those looking for easy money to make bad decisions. In 2014, there were some high profile cases of oyster fraud, theft, and poaching that drew a decent amount of attention from the press and the respective local communities.


Seafood fraud has been a common industry problem that extends beyond oysters. However, as more consumers and restaurants become more engaged with their food and sourcing, traceability will become a higher priority. The Interstate Shellfish Sanitation Conference is working on a more robust traceability plan to be released in the near future. The Vibrio regulations passed this year required growers and distributors to log harvest and transactional details, which provided more traceability, but may have been administratively cumbersome.

TIP As always, work with a reliable vendor and read the tag for yourself. If your Blue Points are being harvested out of Virginia, you are probably not buying Blue Points. This is basic stuff, but be your own detective.


3. Oyster Supply Highly Dependent On Weather

In 2014, all of us felt the winter and spring oyster shortage in some way. The brutal winter did a number on many areas and coupled with other industry factors like the Gulf oyster shortage, it threw the oyster industry into a frenzy.


Unfortunately, most of the factors that plagued the 2014 shortage have not changed. Gulf oysters are not recovering, so expect the Gulf to supplement from the Chesapeake. New England growers continue to grow more oysters each season, but demand continues to outpace supply, therefore farms may sell out again.

The wild card determining supply will be the weather. Weather conditions ranging from wind to ice can prevent oystermen from harvesting farmed and wild product. When farmed oysters are sold out, wild fisheries sustain the market until farmed oysters are back in business. If weather is bad, expect supply to be as tight as 2014.

TIP Teach and educate your customers to be flexible. Yes, I know it's hard, and they want it on their menu all month long, but weather is unpredictable. Help them understand (or refer them to our blog) about what's going on and offer multiple/back up options. Set expectations with your customers now before supply issues come up.

4. More Stringent Vibrio Regulations

Overall, the number of reported Vibrio illnesses across the Northeast at this time is low compared to recent years. Scientists suspect one reason may be that water temperatures were significantly lower than normal early in the summer, which was unusually temperate.
— Connecticut Department of Agriculture

It's obvious that Vibrio risk increases when oyster consumption increases -- more people have the potential to be exposed to the bacteria. This past summer, we saw the new Vibrio control plans in place, which regulated the window of time oystermen could harvest before icing. The short time windows limited the oystermen's catch, and therefore affected available supply. Reported Vibrio illnesses in the Northeast were "low compared to recent years," but could be due to it being cooler than usual in the early summer. Shellfish closures included Martha's Vineyard, MA and Huntington, NY. No confirmed cases were tied to Connecticut, which had a huge recall of Blue Points in 2013.


The regulators' goal is to decrease number of reported illnesses, and the 2014 results would indicate that something is working, so expect strict Vibrio regulations to continue. With that said, Blue Point supply and other affected oysters may be limited again during the summer, but hopefully, oystermen are better prepared this coming year, so supply should be at least the same or better than 2014.

So that about wraps up 2014. It's been a heck of a year, and we can't wait for 2015 and all the challenges that await. Cheers to our customers, vendors, and fans for making 2014 great, but 2015 is going to be even better, so stick around! As always, let us know how we can help, and of course #eatmoreoysters.


Special thanks to Bob Rheault of East Coast Shellfish Growers Association for contributing.