Mechanics of the FoodSaver System

As you may have imagined, the FoodSaver System uses a vacuum device to remove air surrounding the food or drink you want to preserve. As with any vacuum, air is moved from one place to another, which creates a drop in pressure at one point and an increase in pressure at another point. As you may remember from physics class, nature abhors a vacuum and tends to prefer equilibrium. When the pressure is lower in a space than the ambient air pressure, air moves to fill the void.

Air’s movement to fill a void is called communication, and air can communicate quickly — at a speed of about 1,115 feet per second (340 meters per second) [source: LaesieWorks]. That’s as fast as the speed of sound, but that speed can be overcome. This is what the FoodSaver system, and any device that creates suction by creating a drop in air pressure, does. Using a motor that spins a series of fans, air is pushed out of the space — in the case of the FoodSaver, a plastic food storage bag — faster than the ambient air can communicate into the void that’s created. As a result, the bag shrinks around the food and is essentially vacuum-sealed. Upon opening, the bag will make a whooshing sound as air outside the vacuumed space rushes in to fill the void.
The result? Without ambient air exchange, food sealed by the FoodSaver stays fresh about five times longer than it would without storage [source: FoodSaver]. One review of the FoodSaver V3840 reported that sealed packages of meat showed no signs of freezer burn after a month in the freezer [source: Kitchen Contraptions].
The mechanics of the FoodSaver vacuum also allow for quick food preparation as well as storage. A method of marinating called sous vide (“under vacuum” in French) uses a vacuum sealer hose extension and a tray to remove air and open meat for marinating. The void creates a suction effect within the tissue of the meat, causing it to absorb marinades quickly. The FoodSaver System specifically uses a pulse vacuum method for marinating, which vacuums air out of the marinating tray for several minutes, rests for 30 seconds and then resumes air removal once more.
In addition to the vacuum unit, the FoodSaver System also uses a series of sensors to detect conditions inside and outside of the bag. A liquid detection sensor notices when liquid spills out of the top of the bag and automatically shuts the vacuum off. Another sensor detects the presence of a bag and triggers the motor, which starts the vacuum process. When the pressure inside the bag reaches a low level, the machine seals the bag shut using a heating element that fuses each side together.
As complex as the FoodSaver’s mechanics sound, the machine is actually quite easy to use. Read the next page to find out how to use the FoodSaver System.
 
For more detail: How the FoodSaver System Works