Gumbo question for Chef Carey

[Jenise]

A friend posed a question to me this weekend that I couldn't answer.

A former resident of New Orleans, Joan mastered gumbo long ago, and last week she whipped up a batch. Her roux was a deep mahogany, she said. Then she added green bell pepper, celery and onion. Then okra, then tomatoes, seasonings, and eventually shrimp. At this stage it was a good golden color. About five minutes before she was to serve it, she added what she estimated to be 2-3 lbs of frozen dungeness crab meat (home packed without chemicals or preservatives, we all catch our own here), and the gumbo turned black.

Not just dark brown, BLACK, Joan emphasized.

What caused such a rapid and total color change?

[ChefCarey]

A friend posed a question to me this weekend that I couldn't answer.

A former resident of New Orleans, Joan mastered gumbo long ago, and last week she whipped up a batch. Her roux was a deep mahogany, she said. Then she added green bell pepper, celery and onion. Then okra, then tomatoes, seasonings, and eventually shrimp. At this stage it was a good golden color. About five minutes before she was to serve it, she added what she estimated to be 2-3 lbs of frozen dungeness crab meat (home packed without chemicals or preservatives, we all catch our own here), and the gumbo turned black.

Not just dark brown, BLACK, Joan emphasized.

What caused such a rapid and total color change?

This is usually caused by cooking okra in an inadequately seasoned cast iron pot???? Don't know if that was the case here or not.

[Robin Garr]

This is usually caused by cooking okra in an inadequately seasoned cast iron pot???? Don't know if that was the case here or not.

I didn't want to jump in before you answered, Joseph, but I was wondering if this was just a coincidence of timing - maybe the roux was right on the point of turning from dark brown to black roux anyway, and it just happened at the point where she threw the threw the crab in? It's only a short step from dark roux to black roux, and the latter isn't necessarily burned if the cook meant to do it ...

[Jenise]

Robin, but the stew didn't turn immediately black. The mahogany color was diluted to golden with the addition of the tomatoes and chicken broth and it stayed that way during what she said was 45 minutes of simmering. The black occurred only upon the addition of the crab just before serving.

And Chef--see above. I checked with Joan just now and she said she simmered the pot for 45 minutes before adding the crab. Oh, and she used a Creuset Dutch oven.

[Robin Garr]

The black occurred only upon the addition of the crab just before serving.

That really IS strange! I should have figured you wouldn't be asking if the solution was as simple as what I said.

I'm totally befuddled, though. What could there be in crab that would cause a reaction like that? Joseph was certainly our best guru for a gumbo question, but ... this one's strange.

[Jenise]

Yeah, tis a mystery, allright! I made her describe to me exactly what she added, in what order, and how much time elapsed between steps--sure wasn't anything there I could see.

Joseph was

Still is.

[ChefCarey]

Yeah, tis a mystery, allright! I made her describe to me exactly what she added, in what order, and how much time elapsed between steps--sure wasn't anything there I could see.

Joseph was

Still is.

Gumbo ergo sum?

[Mike Filigenzi]

This sounds like the kind of thing that happens when you change pH, but how a batch of frozen crab would change the pH of a gumbo is beyond me. I can't imagine anything acidic being used with the crab???

Mike

[Paul Winalski]

This sounds like the kind of thing that happens when you change pH, but how a batch of frozen crab would change the pH of a gumbo is beyond me. I can't imagine anything acidic being used with the crab???

The tomatoes had already rendered the gumbo acidic. The crab probably released something that chelated the iron, or turned it into ferrous oxide. Perhaps the hemocyanins or some enzyme from the crab blood had a catalytic effect.

-Paul W.

[Jeff Grossman/NYC]

Squid hidden amongst the crab? :^)

[Jenise]

Jeff, LOL. Wish I'd been quick enough to suggest that!