Head-on Versus Headless
Normally I like to buy my products in an as-close-to-
natural state as possible, but shrimp are a major
exception. Shrimp heads contain enzymes that are
held in check while the shrimp is alive. As soon as
they die, however, those enzymes will slowly work
their way into the shrimp’s body, breaking down
tissues and causing them to turn mushy. Even within
a day or two the difference can be striking.
Deheading the shrimp at sea before they are frozen
prevents this mushiness. For this reason, unless I’m
buying shrimp that I can verify were caught within
half a day or so (and are preferably still alive and
kicking), I’ll opt for headless shrimp.
IQF Versus Block-Frozen
IQF stands for Individually Quick Frozen, and the
term means that each shrimp was frozen on its own
before being bagged. Block shrimp come frozen
together in a large block of ice. As a general rule,
the faster you freeze something, the smaller the loss
in textural quality, so go with the IQF. They also
have the advantage that they are much quicker to
defrost.