I have had a few items float a little in my sous vide supreme machine. Mostly veggies. How do I keep them from floating up and stay submerged?
Two things cause bags to fill with air during low temp cooking. The expansion of air that already exists in a product (typical in vegetable cookery), and gas that results in bacterial growth (a problem with some cuts of meat). For vegetable cookery weighting helps, but this is almost always an issue unless you compress a really hard vacuum with a commercial machine. For most home cooks, the best solution is to use zip lock bags, monitor, and then release the air and reseal as it builds up. For meat cookery, try pre-searing for 20 - 30 seconds per side...or dipping in boiling water to kill off any surface bacteria prior to bagging and cooking low temp. Also the sous vide supreme comes with a rack to aid in keeping items submerged. That can help too.
I've had this problem and after trying various things, I've found that this works pretty well:
- I make sure the SVS is filled to the max line
- I cut my own bags from a roll, and make them rather longer than is really necessary - about the internal height if the SVS
- When vacuuming, make sure the contents are kept at one end of the bag
- Then, I place the bags vertically in the SVS, using the stand to hold them in place. By doing this, as the bag starts to float, the top of the bag his the inside of the lid of the SVS and stops the bag rising further - keeping the contents below the water level
My husband came up with a food safe solution for this problem - silicone coated magnets. He had some manufactured and has used them successfully in his own sous vide cooking. Available on Amazon.
The easiest solution is to shove something heavy in the bag with your vegetables before you pack it... like a knife... or weight the bottom of the bags by attaching something heavy to the outside.
From an Anova guide on the subject:
When getting all the air out and preventing the bags from moving is not enough, we look to the next level of options to get those floating bags in check. Weigh the bags down. We can achieve this using both internal and external weighting systems.
Alternately, you can use these same weights externally, instead clipping their sealed pouches to the bottom of your cooking bag with a small bulldog or alligator clip! This is especially helpful when you are batch cooking and plan to transfer your packages directly from the water bath to the refrigerator or freezer (with appropriate chilling in between, of course!).
Other options include "burping" the bag (works better with ziploc-style bags) or putting a heavy weight on top of them to keep them down, usually something heavy, with holes that won't itself be a victim of floating. A vegetable steamer basket (the flower style ones) works well for this.
There are a nice collection of ideas in the article, so it's a good read if the ones I've chosen to mention don't work for you.