Sous vide means “under vacuum” in French, and it’s an extremely precise cooking technique that’s been employed in restaurants for decades. Now, it’s become affordable for the home cook as well! Food is put into pouches, air is removed. Then they’re placed in a tub of temperature controlled water. Some cooks can be as long as 72 hours, and yield amazingly tender results.
You don’t have to have a vacuum device (I have a Food Saver) you can just use an immersion method to remove the air from your pouches.