Thornton - The Sous Vide Bible for UK: 1000-Day Effortless Everyday Meals to Make at Home

Over the course of several years and many, many tests, I've hit upon a couple cool tricks and tips to address problems that sometimes come up when you're cooking sous vide. Here are three that I've found to be the most useful.

No Vacuum Sealer? Use Water Displacement to Seal Your Food in Zipper-Top Bags

Having an easy way to remove air from plastic bags can be handy for all sorts of applications, from marinating meat more effectively to preventing freezer burn and, of course, cooking things sous vide.

Vacuum sealers are designed to do this, but good ones can be prohibitively expensive, and there's a quick, easy, inexpensive option, called the water displacement method, that requires nothing more than a zipper-lock freezer bag and a tub or pot of water.

To do it, start by placing your food inside a zipper-lock bag, then seal the bag, leaving just the last inch or so of the seal open. Next, lower the bag into a pot or tub of water. As the bag gets lowered, water pressure will push air out of the bag through the small opening you've left. Just before the bag is completely submerged, seal off that opening and pull the whole bag out of the tub.

Keep Your Sous Vide Bag Submerged With a Binder Clip

One of the most common sous vide difficulties that I get emails about is floating bags. A few things can cause a bag to float. The first is an imperfect seal, meaning the air is trapped in there to begin with. (This is especially likely to happen if you are using the water displacement method.) With high temperatures or prolonged cooks, vapor can also form inside the bag as water is heated and evaporates, or as air bubbles trapped inside meat or vegetables escape. Bags can also float if the food you're cooking is less dense than water (think sous vide bacon with extra-fatty pieces).

With sous vide cooking, it's absolutely vital that your bags stay submerged and that trapped air bubbles are pushed to the top of the bag and away from the food. This is the only way to guarantee that your food is heating properly, which is important for both food safety and quality.

So how do you get a persistently floating bag to sink? All you've got to do is clamp a large binder clip (like these ACCO clips) on the bottom of the bag, then slip a heavy spoon into the mouth of the clip. The head of the spoon will keep it from falling out, and the weight should keep your food submerged. For especially stubborn bags, you can add a few spoons.

Add Ping-Pong Balls to Your Sous Vide Water Bath

If you cook something sous vide for a long period of time, the water in the bath container can dip to such a low level that your circulator will shut off completely. This not only interrupts the cook time but can pose a serious risk to food safety. To prevent evaporation, you can cover your water bath with plastic wrap or aluminum foil, or cut a sous-vide-device-shaped hole out of an appropriately fitting lid, but I've found that the easiest solution is to dump a bunch of Ping-Pong balls in the bath.

By floating a layer of Ping-Pong balls on the water's surface, you'll simultaneously insulate your bath and help steam to condense and drip back down. The great thing is that Ping-Pong balls will conform to the shape of whatever container you're using and allow you to easily drop bags in and lift them from the bath mid-cook. They're also completely reusable. I keep about 50 of them stored with the rest of my sous vide kit.