Shrimp Sizing

Shrimp is sold by size. Shrimp sizes are expressed in counts per pound or per kilogram. For example, 16/20 means 16 to 20 shrimp per pound. Larger sizes are designated by the term "under" or abbreviated as"U" or"UN." These are expressed as U/10, for example. Other large sizes are U/12 and U/l5 (also referred to as 13/15 for some origins of shrimp). The smaller the count, the larger the size of the shrimp, and generally, the higher the price. Small sizes of shrimp, like coldwater cooked and peeled, will have counts ranging from 150/250, 250/300, etc.

When purchasing shrimp, getting an accurate count is very important. The count should fall within the range stated on the label.

Sizes are sometimes expressed as names instead of numbers, such as jumbo, large, and medium. Although names are widely used, there is no official guideline on what those names signify. If a name is used, particularly at retail, it must be accompanied by the number of shrimp per pound, i.e., the count. The number system is most accurate.

Counts are different when applied to peeled and/or cooked shrimp. The term "finished count" refers to the actual number of peeled shrimp per pound in the package. Another term, "peeled from" count, refers to the count per pound of the shrimp prior to peeling.

Uniformity Ratio

Consistency in count is another important consideration. No matter how shrimp are counted, they should be uniform in size. In other words, the shrimp within a box or bag should be similarly sized within the stated range. To determine the uniformity ratio (UR) of a pack, visually select and weigh not more than 10 percent (by count) of the largest and 10 percent of the smallest shrimp. The chosen samples should be undamaged. Then calculate the UR by dividing the weight of the largest by the weight of the smallest.

The lower the ratio, the more uniform the count. If all the shrimp are exactly the same size, the UR will be 1.0. Given that this ratio is impractical, ratios of 1.25 to 1.75 are more commonly encountered.

There are packs on the market in which sizes vary greatly. While the quality of the shrimp may be good, the random counts may not suit the needs of every operation where uniformity is important. These packs are sometimes referred to as "boat run". However, a more recent industry practice calls them "blended sizes". In these instances, the counts may be 40/60 or 50/80. The uniformity ratio obviously doesn't apply to this pack.