Stainless steel pans are kitchen workhorses, but they have an ever so slight learning curve, particularly when it comes to searing food without it sticking. Letting the pan get nice and hot before even adding the oil is key, but determining the temperature of something by sight is not a skill most humans have.
Luckily, there is a very easy way to tell if your pan is hot enough for a little searing action without any sort of fancy gadget — you just need a little water. Though it may not look like it’s moving, stainless steel expands and contracts with changes in temperature and, according to the Food Network, heating it properly before adding the oil creates a temporarily “static”, nonstick surface.
As Home Ec 101 explains, this is thanks to something known as the 'Leidenfrost effect', a “physical phenomenon in which a liquid, close to a mass that is significantly hotter than the liquid’s boiling point, produces an insulating vapour layer that keeps the liquid from boiling rapidly.”
At this temperature, which is around 190°C, a droplet of water will ball and bounce around the pan, and take longer to evaporate than it would in a slightly cooler pan. (You can also observe this effect by sticking a wet finger in molten lead, but most people don’t have molten lead around.)
Fortunately, even if you don’t fully understand the physics behind this effect, you can use it to check your pan temperature; just get a small glass of water, and a measuring spoon. A spoon that holds an eighth of a teaspoon is ideal, but if you don’t have that you can always eyeball it using a quarter teaspoon. Heat the pan over medium-high heat, and add a few drops of water.
The water will eventually boil away, but it’s not time to add your oil yet. Keep adding water, an eighth of a teaspoon at a time, until it forms a single ball that rolls around the pan before evaporating. Add the oil, let it heat until it starts to shimmer, then add whatever you wish to sear.
You may have to turn the heat down slightly at this point to keep the pan from overheating, so experiment with your stove to find that sweet spot. Once you nail it, you’ll feel very fancy and chef-like, and your food will be the better for it.