Grading Oysters 

Commercial Oysters Grading Standards

Zapco Aquacultures Tumbler and Floating Bag system was designed to produce single seed oysters that are uniform in shape and size . This means it is s very easy to grade and harvest compared to natural grown oysters.

Grading naturally grown oysters is very difficult as the size and shape are not uniform making processing very time-consuming and labour-intensive. 

The market size for an oysters is from 3″ to 4 1/2″ for oysters in the shell. Shucked oysters are designated according to size ranging from the largest “counts” to “smallest”standards.

standard . . . . . . . . . . . . . . . . . . 240 to 400 meats / gallon
select . . . . . . . . . . . . . . . . . . . . . .190 to 239 meats / gallon
extra select . . . . . . . . . . . . . . . .160 to 189 meats / gallon
count . . . . . . . . . . . . . . . . . . . . . .under 160 meats / gallon

There is always a home for any grade of oyster. Despite its shell shape, an oyster still has its flavourful 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.

We have put together a summary of the different sizes and grades . All the different terms can get confusing, so we hope this chart will make it more straightforward and clear for you. If you are donating oysters to your local oyster reef any size oyster over 2 1/2″ up wards is perfect.

Remember if you are going to eat your own oysters make sure you check with your local authorities whether oysters in your location are safe to eat.

Chart of Oyster Grades & Sizes

Shell Size

Atlantic Ocean

Canadian Maritime

Pacific Ocean

2 to 2.5 inches

– – – – –

– – – – –

Cocktail

2.5 to 3 inches

Petite

Cocktail

X-small

3 to 3.5 inches

Market

Small

Small

3.5 to 4 inches

Market

Large

Small

4 to 5 inches

XL

Large

Medium

5 inches +

Jumbo

Large

Large

Grade

Price

Characteristics & Use

Commercial

Budget

Very difficult to shuck – used for oyster meat processing

Standard

Moderate

Some curved or lightly misshaped shell – can be used for meat processing, stuffing, or half-shell consumption.

Choice or Select

Premium

Nice cup depth and shape – typically used for half-shell consumption