The pork belly can be replaced with a piece of pork shoulder cut in half horizontally.
Ponzu is a citrus-based, slightly acidic soy sauce. It can be found in the Asian products section of your grocery store.
To remove the air from a freezer bag with a slider closing or a silicone bag, hold the bag open at the top while slowly lowering it into the water. The pressure of the water will squeeze the air out of the bag. Just before the top of the bag reaches the water, zip it closed.
If using a freezer bag with a slider closing or one made of silicone, do not submerge the seal of the bag. Clip the top of the bag to the side of the cooking container ensuring the seal will not go underwater to prevent liquid from leaking into the bag.
It is important to ensure the food is fully submerged under water throughout cooking. If the food bag floats, use a heavy, heat-resistant utensil, a plate or RICARDO magnetic weights to hold the bag down and keep the food submerged.
To regulate the temperature and make sure the water level doesn’t trop too much, cover the pot with plastic wrap or use a RICARDO silicon lid, designed for this use.
The rutabaga purée can be prepared while the pork is cooking sous vide and then refrigerated. Simply reheat the purée while you are browning up the pork.