Sous vide troubleshooting

Matt__34377

Hey all.

I've been finding when I cook beef and lamb sous vide for long periods of time (24hrs+) it comes out with a brown-green layer on the outside, but is perfect in the middle. It doesn't affect the taste and doesn't smell off but it's not very aesthetically pleasing. Haven't had this problem with pork or chicken, but I also haven't cooked either for any more than a few hours. Just curious what may cause this or if it is inevitable and it just has to be trimmed. I use Foodsaver bags to pack the meat. Don't know if that makes a difference.

Thanks so much!!

Isaac_Moreira_4911

We can see it very clearly on this recipe:http://www.chefsteps.com/activities/tough-cuts-transformed

At first i was intrigued but, since it's safe, no worries... It makes me think if it has something to do with the plastic bag. Eggs yolks turn green wen exposed to certain amounts of heat and just in the outside layer of the yolk because of the high sulfur concentration on that layer. I wonder if the long period of cooking is responsible for the formation of hydrogen sulfide due to the reaction from the sulphur that is present on the meat and the hydrogen that permeates the bag, since it's a really small molecule...