In sous vide, size matters. Recently, I began using an inexpensive set of plastic calipers that I picked up online. They have proven to be a very easy and effective tool for taking the measurements I need to feed into the SousVide Dash app, and as a result I am likely to use them for almost everything I cook sous vide.
The thickness of a piece of food has a very direct impact on the length of time it needs to cook sous vide. Cooking time is roughly proportional to the square of the smallest dimension of the food. So if one steak is 50% thicker than another, it will take approximately
1.5 * 1.5 – 1 = 2.25 – 1 = 125%
longer to cook. So it is critical that we measure the dimensions of food accurately.
Recently, I discovered the General Tools 141ME Pocket Caliper and added it to my sous vide toolkit. It is made of plastic, and costs less than $8 with free shipping. Similar models can be found elsewhere on the web for as low as $2, though shipping can jack up their prices quite a bit. Here’s what it looks like measuring the diameter of an egg:
Notice how easy it is to read the scale down to the millimeter of 1/32nd of an inch.
Of course there are a number of other methods in common use for measuring the thickness of foods to be cooked sous vide. Some people use an ordinary ruler, though it is sometimes tough to eyeball exactly where the food lines up. Some people have taken it even further and written apps that display a ruler at actual size on the screen of a smart phone. So now you still have the problem of lining things up, but you are also putting your smart phone down onto the kitchen counter where something could easily spill on it.
Over on eGullet.com, PedroG produced a handy sous vide thickness ruler that you can print out and use on the edge of your countertop. I have used this before, and I always liked it except for the fact that it is only ruled at 5mm intervals. I also have to reprint it regularly when it gets wrinkled, folded, or wet.
In my experience, none of the other methods above has been as good as this set of calipers.
I have had great luck with the calipers with a variety of foods. Aside from being extremely accurate, they are small and lightweight enough to fit easily in a kitchen tool drawer, yet durable enough for kitchen use. Since they are plastic they wash easily with standard dishwashing liquid and water if anything spills on them. So far I’m very happy with them and would recommend them to others who cook sous vide.