Cooking with an immersion circulator falls into the low-and-slow category. That means you're using relatively low heat over a relatively long time to cook food. Instead of cranking up the stovetop or grill and cooking a cut of meat in less than 10 minutes, you immerse the vacuum-sealed meat in a hot water bath for up to a few days. But why would anyone do that?
The gradual cooking method allows you to cook through food completely from the outside to the core. By setting the heat of the water at a precise temperature, you can transfer heat to cook the food evenly. Other methods of cooking can result in uneven cooking. For example, a grill might be so hot as to cook the outside of a cut of meat while keeping the inside undercooked. Leaving the food on long enough to cook through could mean you end up burning the outside edge.
By cooking at lower temperatures, you can also avoid damaging the food you're cooking. Cook food at too high a temperature and you'll break down the cellular walls within the food itself. Using the correct temperature in a water bath, you can avoid overcooking foods.
According to chefs, the vacuum seal helps ensure that food cooked in the sous-vide style tastes as flavorful as possible. They say that because the food isn't losing juices and flavors to the air and water around it, they remain within the food itself. And the air-tight seal on the plastic bag helps keep food moist as it cooks, meaning you won't end up with a dried-out meal at the end.
Because water makes up a large amount of the mass of many foods, using a cooking method that preserves moisture within a food also avoids shrinkage. If you've ever grilled a hamburger and noticed that the finished burger is noticeably smaller than the patty you made, part of the reason is because the burger loses mass in the form of water as you cook it. The water evaporates out and the burger loses that mass.
With a precise immersion circulator, you can also count on the consistency of this cooking method. As long as you account for the type and amount of food you're cooking, using this method should produce the same results every time. While you may have to estimate cooking times for less precise methods of cooking -- such as using a charcoal grill -- the sous-vide method relies on nearly scientific precision to create replicable results.
The biggest drawback of the sous-vide method is that it requires a lot of time to cook certain foods -- sometimes requiring several days. It's not the cooking method to break out 20 minutes before dinner. But with the right time and equipment, cooking with an immersion thermal circulator can help you create a flavorful meal.