Flavor – flavor development

Sous vide not only keeps the proteins (main component) at a lower temperature, but also the spices/oils/flavorings. Heat helps release the taste and aroma of all the ingredients, and the sous vide might not be hot enough to do that.

So, while it kind of kills the simplicity, you could always sautee the seasonings in oil before adding them to the sous vide bag (not until cooler though). Or just keep them separate and recombine for serving. Sous vide itself (not the vacuum part) is mainly for maintaining/achieving a controlled internal temperature, and skilled cooks don't only sous vide a dish; they might sous vide and then finish under a broiler for texture, or with a torch. If the sauce isn't working inside the bag, make it work outside the bag.

Alternately, put the ingredients in the bag the day before, and let them marinate overnight in the fridge. The vacuum action is essentially just a speeded up marinade, so this should do the same.

Also, make sure you're using enough (but not too much) SALT.

Finally, call the Sous Vide Supreme company. They know their product's capabilities and limitations and might have some good recommendations.

Just my guesses.

I have had this problem and thought it was the taste of tin-foil that I used to rolled up and put into the belly of the fish to stand it up in the oven. So, I was very interested to hear an interviewer on the radio 3RRR in melbourne, talking to a chef who mentioned fish, like Snapper, are susceptible to that metalic taste if they are caught and die too slowly. The slower they take to die, the more stress the fish goes through and the stress hormone accumulates in the flesh particularly around the belly. I think they said a pinker snapper is better than a pale one for taste.