re: Gumbo a little thin...

You can do as suggested and let it simmer a bit uncovered which will reduce the liquid. Another option is to either use some of the jarred roux or make another small roux. Warm the roux and add a little of the simmering gumbo liquid to it, stirring to make somewhat of a slurry. Then, stir that into the gumbo and see if you get the texture you want. You can keep doing it until you get the texture, but if it's only a little thin, it shouldn't take much.