January 18, 2021
Oyster Sizing and Grade Guide
While sizing practices differ between countries, in the UK, live oysters are graded into 4 sizes with grade 4 being the smallest, and 1 being the largest. Size is determined by measuring the longest length of the shell, while continental markets tend to grade oysters based on their weight. Oysters are separated into 5 groupings: European, Pacific, Kumamoto, Atlantic, and Olympia.