How often do you need to change the water in your Sous Vide machine? Given food never touches the water I don't think I need to change it every time, but it does seem like I should change it once in awhile. Any rules of thumb?
The water frequently sits in the danger zone for bacterial growth, and even though it is a sealed bag, fats can migrate through the plastic (not considering contamination to the outside of the bag either from cross contamination or from juices drawn out during vacuuming/sealing).
I would suggest changing the water if:
Additionally from the PloyScience site:
So you can probably throw a little vinegar into the water to up the pH and make it more hostile to bacteria (though it will smell up the house when you use it).