Skip to Content

What happens to a blue lobster when you cook it?


Blue lobsters are incredibly rare – occurring in only 1 out of every 2 million lobsters. Their brilliant indigo color is caused by a genetic defect that causes the lobster to produce an excessive amount of a particular protein. When blue lobsters are cooked, their unique coloration results in some interesting changes compared to normal reddish-brown lobsters. Keep reading to learn more about how heat impacts the proteins and pigments in blue lobster shells during cooking.

Why Are Blue Lobsters Blue?

Lobsters get their normal reddish-brown hue from astaxanthin proteins built up in their shell over their lifetime. Astaxanthins are carotenoid pigments produced by algae and plankton, which turn lobsters red when they eat these organisms.

Blue lobsters, on the other hand, get their rare color from an overproduction of a different protein – crustacyanin – in their carapace (shell). When an overabundance of crustacyanin is present, it binds to the astaxanthin pigments and turns the lobster blue.

This overproduction of crustacyanin is caused by a genetic mutation, similar to conditions like albinism in other animals. While cool to look at, it does not appear to affect the lobster’s lifecycle or lifespan.

How Does Heat Impact the Pigments?

When a blue lobster is cooked, whether by steaming, boiling, or other wet cooking methods, the heat causes changes to the pigments and proteins responsible for its coloration:

  • Astaxanthin begins breaking down at temperatures above 100°C/212°F.
  • The crustacyanin proteins start to denature and unwind in hot water, causing them to lose their ability to bind to astaxanthin.
  • As this color-binding reaction is lost, the brilliant blue hues start fading back to red.

This unwinding of the crustacyanin proteins occurs because heat increases the kinetic energy and molecular vibrations within the lobster shell. This energy disrupts the delicate protein structures, causing them to deform and denature.

What Visual Changes Occur During Cooking?

As a blue lobster is cooked, several striking visual changes can be observed:

  • The blue color will start fading within the first 1-2 minutes of cooking.
  • Often, the color change will progress from the tail forward towards the head.
  • After about 10 minutes of wet cooking, the blue hues are completely gone, leaving a reddish-brown lobster.
  • The color transition may appear patchy, with some spots maintaining blue longer than others.
  • The blue colors will never return once cooked, even if chilled.

Here is a simple table summarizing the visual changes:

Time Color
0 mins Vibrant blue throughout
1-2 mins Blue fading, especially on tail
5 mins Mostly reddish-brown, some blue spots
10+ mins Fully red appearance

As these changes indicate, the unstable blue pigments degrade quickly with heat, while the much more stable astaxanthin proteins remain intact.

Why Do the Changes Happen So Quickly?

You may be wondering why the brilliant blue hues fade so rapidly during cooking. There are two primary reasons:

  1. Low thermal stability of crustacyanin – The crustacyanin proteins are delicate and not very heat tolerant. Their structures unwind quickly with increasing temperature.
  2. High porosity of lobster shells – Lobster exoskeletons are full of tiny pores to allow gas exchange, which lets hot water rapidly penetrate deep into the shell.

The combination of these two factors means heat can swiftly reach the vulnerable crustacyanin proteins and cause them to denature.

For contrast, dense exoskeletons of insects and crabs better protect their interior pigments from heat damage. This results in slower color changes when cooking them.

How Does Cooking Impact Flavor and Texture?

While the color changes are the most dramatic effect, cooking also impacts the flavor, meat texture, and shell texture of a blue lobster:

  • Flavor – Cooking condenses and concentrates the flavorful proteins within the lobster meat, resulting in a richer, more intense taste compared to raw.
  • Meat texture – Heat denatures and firms up the proteins in lobster meat, turning it from a translucent raw texture to an opaque, flaky cooked texture.
  • Shell texture – The shells become more rigid but slightly brittle after cooking. Too much cooking makes them crack more easily.

The ideal cooking time preserves maximum flavor while achieving the desired texture for both the meat and shells. Steaming or boiling for 8-12 minutes is generally recommended.

Does Color Change Impact Nutrition?

Many people rightly wonder if the pigment changes impact the nutrition of blue lobster meat. The answer is thankfully no – the color alterations are purely cosmetic and do not affect nutritional quality.

A few key facts about cooked blue lobster nutrition:

  • Still high in protein like regular lobster, with around 20g protein per 3 ounce serving.
  • Rich in B12, selenium, copper, zinc and other minerals.
  • Contains omega-3 fatty acids, mainly DHA and EPA.
  • Low in saturated fat and calories, providing only around 90 calories per 3 ounces.

So while the appearance changes, the excellent nutritional value remains whether the shell is blue or red!

Can You Delay the Color Change?

Some chefs or lobster fans may try to delay the inevitable color change during cooking for presentation purposes. A few potential methods include:

  • Chilling the lobster meat before cooking to prolong heat penetration into the flesh.
  • Boiling in a large pot of water to reduce temperature change rate.
  • Tempering – bringing to heat slowly instead of dropping straight into boiling water.
  • Cooking in the shell to preserve pigments longer.
  • Cooking for the minimum amount of time needed for food safety and texture.

However, these methods can only slow the color change by a minute or two. Eventually the delicate crustacyanin proteins will unwind. But skilled chefs may be able to time dishes like tempura or stir-fries to serve immediately after cooking before all the color is lost.


While many are familiar with how heat impacts a normal brown lobster, the brilliant blue hue of rare genetic mutant lobsters introduces some interesting protein chemistry into cooking. Their one-of-a-kind coloration comes from proteins that rapidly denature when exposed to hot water or steam. Within minutes, a vibrant blue lobster will fade back to red as these unstable pigment-binding proteins unwind and release their grip on astaxanthin. While the visual impact is stunning, cooking has little effect on the prized flavor and nutrition – so blue lobster remains a deliciousdelicacy however you prepare it.