Stainless Steel: Heat Check

Knowing when your stainless steel pan is hot enough is essential to avoid food sticking. Luckily, there's a simple way to test the temperature without any fancy gadgets. This method is called the water drop test or the mercury ball test, and it works thanks to the Leidenfrost effect, a phenomenon where a liquid close to a mass that is significantly hotter than its boiling point produces an insulating vapour layer that keeps the liquid from boiling rapidly. In the case of water on a hot stainless steel pan, the water will form a small ball that glides around the pan before evaporating. This indicates that the pan is hot enough.

The water drop test: a teaspoon of water should form a blob and glide around the surface

The water drop test is a simple and effective way to tell if your stainless steel pan is hot enough without needing a thermometer. It works thanks to the Leidenfrost effect, a physical phenomenon where a liquid close to a mass that is significantly hotter than its boiling point produces an insulating vapour layer that keeps the liquid from boiling rapidly. In this case, when the pan is hot enough, the water will form a ball and roll around the pan's surface without fizzing, splitting, or evaporating.

To perform the water drop test, first heat your pan over medium-high heat for 2-3 minutes. Then, add a teaspoon of water to the pan. If the water droplet forms a single ball and glides around the pan, your pan is hot enough. If the water fizzes, splits into multiple droplets, or evaporates, the pan is not hot enough. You may need to keep adding water, an eighth of a teaspoon at a time, until the desired effect is achieved.

It's important to note that the water drop test only works for uncoated stainless steel pans. Coated stainless steel pans, such as those with a Teflon or ceramic coating, should not be preheated without food or oil as this can lead to the release of harmful fumes and a loss of non-stick properties.

Additionally, while the water drop test is a reliable method, it can take some practice to get the hang of keeping your pan within this narrow temperature window. You may need to reduce the heat slightly after adding oil to prevent the pan from overheating.

The Leidenfrost effect: water should form small beads that move around and don't evaporate quickly

The Leidenfrost effect is a physical phenomenon where a liquid, close to a solid surface that is significantly hotter than the liquid's boiling point, produces an insulating vapour layer that keeps the liquid from boiling rapidly. This effect is commonly seen when cooking, when drops of water are sprinkled onto a hot pan.

If the pan's temperature is at or above the Leidenfrost point, which is approximately 193°C (379°F) for water, the water skitters across the pan and takes longer to evaporate than it would at a lower temperature. The water forms small beads that move around the pan and do not evaporate quickly. This is because, at temperatures at or above the Leidenfrost point, the bottom part of the water droplet vaporises immediately on contact with the hot pan. The resulting gas suspends the rest of the water droplet just above the pan, preventing any further direct contact between the liquid water and the hot pan. As steam has much poorer thermal conductivity than the metal pan, the heat transfer between the pan and the droplet is slowed down dramatically. This also results in the drop being able to skid around the pan on the layer of gas just under it.

The Leidenfrost effect can be used to tell if your stainless steel pan is hot enough for cooking. Simply heat the pan for 2-3 minutes and add a teaspoon of water. If the water forms a blob and glides around the surface, the pan is hot enough. If the water fizzes, splits into tiny droplets, or evaporates, the pan is not hot enough.

The mercury ball test: water should roll around like a ball of mercury on the surface

The mercury ball test is a reliable way to test if your pan has reached the perfect temperature to become non-stick. It is also known as the "water drop test".

To perform the test, first, ensure your pan is washed and dried thoroughly. Then, place the pan on medium-high heat and wait for it to heat up.

Next, gently drop a teaspoon of water into the pan. The water should form a single ball that rolls around the pan before evaporating. If the water fizzes, splits into multiple droplets, or evaporates too quickly, the pan is not hot enough.

Once the water has formed a ball and is rolling around the pan, pour off the water and add oil to the pan, spreading it across the surface. You should then add your food right away, as you don't want the pan to overheat.

The mercury ball test works because when stainless steel cookware heats up, the metal expands, making the microscopic pores smaller so food particles can't get in. This creates a non-stick surface.

The mercury ball test is not the only way to test if your pan is hot enough. Another method is to simply hover your hand 4-5 inches above the surface of the pan. If you can feel heat coming off the pan, it is hot enough.

Heat the pan: heat the pan for 2-3 minutes before adding oil

Heating your stainless steel pan before adding oil is an important step to ensure your food doesn't stick to the pan. Stainless steel pans have a slight learning curve, but heating them correctly will ensure you get the best results.

The first step is to place your stainless steel pan on the burner and set the heat to medium-high. This setting allows the pan to heat up gradually and evenly. Allow the pan to heat for about 2-3 minutes. It's important not to rush this step as it ensures your food will cook evenly and be released from the pan more easily.

Once the pan has heated for 2-3 minutes, you can perform the "water test" to check if the pan is hot enough. Simply flick a few droplets of water onto the pan. If the pan is hot enough, the water will form a ball and glide around the surface of the pan, like a ball of mercury. This is called the "mercury ball test" and it indicates that the metal has expanded, creating a non-stick surface.

If the water fizzes, splits into tiny droplets, or evaporates, the pan is not hot enough yet. Keep heating the pan and continue to add water, a few drops at a time, until the water forms a single ball that rolls around the pan.

Once the water test indicates that the pan is hot enough, it's time to add the oil. Pour off the water, quickly add a thin layer of oil, and spread it across the pan. Wait for the oil to heat up for about 30 seconds to a minute, or until it begins to shimmer, before adding your ingredients.

It's important to note that you should not add oil to a screaming hot pan as it may burn. If the water droplet rolls around the pan very quickly, you can lower the heat slightly before adding the oil. Additionally, be sure to use enough oil to coat the bottom of the pan evenly. This will help prevent food from sticking.

Oil temperature: oil should be shimmering and coat the bottom of the pan

Oil temperature is crucial when cooking with a stainless steel pan. Adding oil to a hot pan creates a barrier between the food and the pan, preventing sticking. To know when your oil is hot enough, look out for a shimmering effect. The oil will also coat the bottom of the pan in an even layer with just a little shimmying of the pan. Think of it like an oil slick or heat waves rising off the sidewalk on a hot day.

The shimmering effect is a result of the oil thinning out and moving in a looser, more fluid manner as it heats up. This is when you know your pan is hot enough to add food. If the oil doesn't coat the pan, you likely don't have enough oil, and you risk food sticking to the pan.

If you're cooking something in a shallow pan fry with 1/8" of oil or more in the bottom of the pan, you can insert the end of a wooden spoon or a chopstick into the oil to check if it's hot enough. If the wood bubbles, the oil is ready.

It's important to note that you should always heat your stainless steel pan before adding oil. This is because the metal of the pan expands slightly when heated, closing any minuscule fissures, pores, or gaps in the surface. This creates a smoother surface for the oil to slide on and prevents food from getting stuck in the pores as they close.

Additionally, heating the pan first and then adding oil helps to prevent the oil from getting trapped in the fissures as the pan cools, making it easier to clean. It also brings the oil up to the appropriate temperature faster than if you were to add it to a cold pan.

So, the key steps are: heat the pan, add oil, wait for the shimmering effect, and then add your food.

Frequently asked questions