I thought that any of plastic bag is good for a long time sous vide cooking! Now, put ashes on my head, and regret that I did not check it! Why? Read the whole story!
Three weeks ago i bought a good quality plastic bags (said to be reliable manufacturer). The box of the plastic bag said: this product can be use in a freezer and a MICROWAVE OVEN! Hoho, if i can use it in microwave, it bears the warmth, ergo it's perfect for sous vide cooking! I tried it immediately, put some half cutted champion, some butter, little bit salt and pepper into the plastic bag, and drop it to 70 °C (160 F) sous vide bath. Tadammm! 1 hours later the mushroom well cooked, i've got a perfect taste meal, which had only to pour a small amount of cream.
Ok! Let's try a little bit harder quest! What if i cook some green asparagus longer time, for example 2 - 3 hours? The following day was the day of experiment. I put some green asparagus and butter into the plastic bag, and gently dipped into the water, so that the excess air go out of it. I closed the bag, and pay attention to what is going to happen in the 75 °C (168 F) sous vide bath.
I totally forgot my other activites, therefore i had to go to my friends.
From 2 - 3 hours was 5 - 6 hours! After, i came back my first thing is to check the state of my asparagus. I saw, that the water color greenish, and little obscure. I've switched off the sous vide machine, and tried to taken out the bag from the hot water.
That point struck the crash! The bottom of the bag was opened in the soldering, the bag filled with hot water, and the valuable nutrients get mixed up in it. How I shall make the trouble, even the asparagus slid into the water through the slot.
The plastic bag did not endure the long hours heat. At least, i packed the asparagus into bacon, and baked in the electric oven... :(