We see a lot of people asking us, about preventing evaporation, with lot of suggestions ranging from custom cut cambro tank lids to just “keeping the water topped up”. A method, which only uses plastic wrap, is the most popular today and it is relatively easy to prepare, if you have 10 minutes per day to do it. Although easy and very effective to stop evaporation, it uses a lot of cling film and we all know the cost of each roll. Doing this daily costs a lot of money per year.
Here is an explanation of how to use this type of solution and I show this as it is the best I have come across recently. First, fill your tank/pot etc. to the required level depending on your circulator. Add your bagged food so you know the level is correct before you seal it up. Then, seal the entire container with plastic wrap, overlapping a few times so that it’s fitted firmly and down the sides enough that it won’t slip later. You then cut a small hole that barely fits your circulator. Hold its base against the plastic till you can judge it by eye. Be careful not to slice into any bags. Slide the circulator in and fasten. If you’ve been careful it’ll be a snug fit, which is perfect. Turn it on and start your cook. It’s also handy to write the time / temp on the plastic if it helps you remember when to take it off.
Excerpt from:
http://www.sousvideblog.com/preventing-evaporation-for-extended-sous-vide-cooking/
Problem… what happens if you need to get into the pot, or you want to check the tenderness, or what if there is a power failure, etc.etc.etc.
Rely have a solution, ‘BoB’. We have manufactured one of our ‘Ultrabags’ to have a zip on it and become a two in one product. In the bag are 450 polished PP balls that are FDA approved for foodservice. Simply tip the bag on top of the water and hey presto a perfect barrier to stop condensation. Also it is very easy to enter and exit product. We have trialled the product extensively and find little or no water loss over 72 hours at 70°c. The spheres can be collected in the bag and washed in a dishwasher, or stored for later use. The cost is a one off, about the same price as two rolls of film. The bag is also useful. It is after all an Ultrabag and can be used as a flexible sieve. At 200microns it can clarify stocks and get perfectly strained products. We believe the product can last for many years. Contact Lynda or myself for more details. 03 55620002., or www.relyservices.com.au