This week, we’re taking a look at stainless steel cookware. Stainless is supposed to be one of the best and safest forms of cookware, but as I’ve said before, quality matters. So how do you know if one type of stainless steel is better than another? Is there a way to test stainless steel for quality?
Let’s find out!
Question of the Week
Martha asks:
I was reading your article about cookware.. Last year I bought a set of stainless steel pans. How do I know if they are good quality?… and according to the information they are top quality. I try with a magnet and it will stick all over the pan just not inside… How can I make sure they are safe to cook? I’m totally changing my non-stick for more stainless or cast iron. Thank you for all your info. I cook a lot with butter… I love it!
This is a topic that a lot of people seem to be unsure about—I know I definitely was for quite a while! You hear so many different things about stainless steel. Some say it’s totally safe and non-reactive. Some say it leaches dangerous heavy metals into your food. Some say it’s the best thing ever and the only cookware you should use. Some say it’s only safe if it’s magnetic steel, which it sounds like you’ve heard before. You might have even heard it from me—that’s what I thought was the best way to test for quality, too! I’ve since learned some more information that might help you out.
So, let’s start with that whole magnetic thing. This is a confusing topic!
What’s the deal with magnetic stainless steel?
The theory of the “magnet test,” is sort of this rumor going around in which you’re supposed to test the quality of the stainless steel with a magnet. But really what this tests for, is whether or not the steel is austenitic, or made of a metal alloy which contains chromium and nickel.
There are three main types of structures in stainless steel—austenite, ferrite, and martensite. When you see stainless steel labeled as 18/8 or 18/10 this is telling you how much chromium and nickel is in the steel. The first number indicates 18% chromium, and the second 8% or 10% nickel. The nickel is the key to forming austenite stainless steel. Both the 18/8 and 18/10 are therefore austenitic.
So the “magnet test” is to take a magnet to your stainless steel cookware, and if it sticks, it’s “safe”—indicating no nickel present—but if it doesn’t stick, then it’s not safe, and contains nickel (which is an austenite steel). It is true that if a magnet were to stick to the steel, that it would not be a nickel (austenite) alloy.
There’s a problem with this theory, however. For one thing, there are no stainless steel pans which are magnetic on both the outside AND the inside. Someone please correct me if I’m wrong, but I have searched and searched and searched, and have yet to come across a fully-magnetic piece of stainless steel cookware.
And there is a good reason for this—austenitic, or nickel-containing, non-magnetic stainless steel, is highly resistant to corrosion, which is super important if you’re cooking directly on it. If the piece was fully magnetic stainless steel, it would corrode and not last very long without the nickel to stabilize the metal. Even though it would be nickel-free, I don’t think I would even want a magnetic, 18/0 stainless steel pan for this reason!
You will find magnetic stainless steel in the layer on the outside of some quality pieces of stainless steel. This is to make it compatible with induction stovetops, which involve the use of a rapidly charging electromagnetic field to heat cookware. High-quality stainless steel, good quality manufacturers use three layers of metal—the austenite layer of steel on the inside, ferrite steel on the outside, and a layer of aluminum sandwiched between the two for optimal heat conductivity (steel alone does not conduct heat evenly). Lesser-quality stainless steel is usually just one layer of austenitic stainless steel.
But there is still a difference in quality between the types of austenitic, or non-magnetic, stainless steel. You’ll sometimes find that austenitic stainless steel is weakly magnetized, and that’s because of the manufacturing process. You can actually form ferrite and martensite by “cold-working” the steel, which does make it more prone to corrosion and leaching.
The formulation of austenite in high-end, quality stainless steel cookware is created with a process which is careful to avoid this. It leads to an austenite alloy which is very stable and resistant to corrosion and leaching of metals. I’m no metallurgist, but in my opinion, a carefully-formed and highly-stable, non-corrosive, nickel-containing stainless steel is safer than a purely magnetic stainless steel which could break down and corrode over time. (And which doesn’t even exist on the market, anyway!)
If you know anyone who has had good quality stainless steel cookware for a number of years, you can tell just by looking at it compared with cheap stainless steel, that it is indeed very resistant to corrosion and holds up well over time.
But, to answer your original question,
How do you know if your stainless is high quality?
Well, unless you’re a metals expert and go inspect the factory where the steel is made to see whether or not their manufacturing process creates a pure austenite without corrosive materials formed, you’re not going to know for sure whether or not the craftsmanship of your stainless is of the highest quality. I think your best bet is to simply buy high-quality stainless steel from the start, from a brand with a reputation for good quality. But, I think I have figured out one way that you can determine if the stainless cookware you already have is potentially reactive.
The Vinegar Test
I read that you can test the quality (or more accurately, the reactivity) of the steel by boiling some water with a tablespoon of baking soda in the pan for a few minutes. If the water has a metallic taste, then the steel is reactive and of lesser-quality.
But from what I’ve learned about stainless steel, my understanding was that it’s the acidic foods you have to worry about, when it comes to any leaching from stainless steel. And baking soda is alkaline. So, I decided to do a little science experiment and try a different test!
Here’s what I did:
I poured a couple tablespoons of plain white vinegar (which is of course, quite acidic) into two spoons — good quality spoon, and another generic stainless steel spoon I had lying around. I also put some of the vinegar into a glass cup as a control.
After a few minutes, I taste-tested the vinegar from each.The good quality spoon`s vinegar tasted exactly like the vinegar in the glass cup. But the vinegar in the cheap, generic stainless pan tasted like metal. Blech. The taste is still in my mouth as I type!
I’m pretty convinced my vinegar test is a decent way to determine the reactivity of your stainless steel. Try it out on yours and see if it passes! But if it doesn’t, I wouldn’t freak out over this. Just be mindful about cooking with very acidic things like tomato-based sauces and stuff, and avoid storing these foods in your stainless steel.
thank you to Emily Benfit at (http://butterbeliever.com/how-to-tell-quality-of-stainless-steel-cookware/)
When sourcing raw steel plate, purchasing managers have three primary steel plate sources: retailers, suppliers (also known as distributors) or mills.
Retailers include everything from big-box chains – such as Home Depot – to independent metal specialists, in-stores and online. With retailers, customers can simply walk into a store or browse a website, select an item and purchase the item at will.
Suppliers are “material middlemen.” They buy steel plate in bulk from a mill at discounted rates, store it in high quantities in warehouses and then sell the material to buyers with medium or high quantity needs.
Suppliers often sell by the “truckload,” or between 20,000 lbs. and 40,000 lbs. Suppliers offer a greater selection of steel plate product at lower per-hundredweight cost than retailers, since they deal primarily in bulk.
Mills are the producers of steel plate materials and offer a varied selection of steel plate product. In most cases, mills only sell direct to buyers in need of very large volumes of steel plate.
Service centers are another common source for processed steel plate (such as plate cut to specific sizes or shapes), but we will not focus on service centers in this article due to the variety of metal processing service options.
Related: Common Ways Steel Plate is Processed
So which steel plate source is best for you? The answer depends on buyer needs surrounding five primary factors:
Understanding your specific needs in each category will help determine which sourcing method(s) may be best for you.
The most distinct difference between buying from retailers, suppliers and mills is the degree of convenience offered by each source.
Retailers are highly convenient. They carry very few steel plate products, but have these products readily available at all times. Retailers typically allow buyers to place a steel plate order via their website, which gives buyers the option to buy plate in just a few clicks.
Suppliers are significantly more convenient than mills, because they often have deep inventories and multiple inventory locations. They can respond to steel plate needs quickly (sometimes even within the same day), whereas mills usually require more than a month lead time on an order. Some suppliers, like Leeco Steel, are beginning to offer customers the option of ordering steel plate online via an ecommerce website to add convenience to the buying process.
Additionally, suppliers usually have experienced in-house teams that understand how to deliver large steel plate orders, which is an important convenience for many medium-to-large volume buyers.
Mills offer the lowest level of convenience, as they fill their production “books” (AKA: schedules) months in advance. Suppliers and retailers can handle these longer lead times due to large on-hand inventories, but buyers typically cannot. This is why only large buyers with specific, known material needs tend to purchase steel plate directly from mills.
Retailers usually accept cash, check or credit card payments at the time the order is placed, making them highly convenient for smaller buyers.
Suppliers and mills almost never accept credit card payments due the large value of the average order. In fact, most suppliers and mills require buyers to undergo a business credit evaluation before the buyer can even buy.
Once a supplier or mill extend credit limits, buyers do have the convenience to place orders in advance but pay when material is received. In these situations, mills adhere to a strict 30-day payment window.
Suppliers have dedicated credit evaluation teams to assess credit risk and can therefore offer more flexible payment windows (i.e. 45-60 days), making them more convenient for medium-to-large buyers.
Retailers offer a limited variety of steel plate products. They typically only carry common grades, such as ASTM A36 and AR400, and usually only in smaller sizes.
Mills, of course, offer the highest degree of product variety, as they can produce-to-order hundreds of grades across a wide range of thicknesses, lengths and widths.
Suppliers may not carry as wide of a variety of grades as mills, but they can often quickly procure whatever grades and sizes are needed because they buy from a network of mills. In these situations, suppliers offer a service to customers by doing the sourcing leg-work for them.
Steel plate is priced per hundredweight – or cwt. Retailers offer significantly higher cwt than suppliers and mills as a tradeoff for the convenience of immediate product access and easy cash or credit payment.
Related: How much does steel plate cost?
Suppliers have stronger buying relationships with mills that allow them to buy steel plate at more competitive rates than retailers and most large buyers. Additionally, suppliers usually have lower operational overhead, as they have fewer facilities and greater fulfillment efficiencies, since their orders are larger in volume.
Mills can sometimes offer a lower cwt price than suppliers (depends on the grade), but they only sell to very high-volume buyers, and orders can take months to fulfill. What buyers might get with cost savings, they lose with convenience and speed.
The volume of a buyer’s need often helps narrow the choice of supplier. Retailers specialize in handling low-volume needs, especially orders less than 200lbs. Orders under 200lbs. can be shipped via standard ship methods, unlike heavier orders that require freight transit.
Suppliers’ sweet spot is any order greater than 20,000 lbs./10 tons (about half a truckload) up to whatever inventory limitations the supplier has for the requested grade and size.
It’s not that suppliers would never fulfill a low-volume need, it’s often that they simply do not have small-sized material. Most steel plate stocked by suppliers is 8-10ft wide by 20-40ft long. This would be well beyond the volume need of many retail customers, who typically request plate under 2ft wide by 2ft long.
Mills, on the other hand, thrive on high-volume orders. Mills produce heats – or batches – of steel plate products, usually in quantities of 120-150 tons per heat. When mills supply to direct buyers, they are usually supplying one or more heats multiple times per year.
One huge advantage of buying steel plate from suppliers or retailers is reduced inventory risk. Buyers can receive the exact inventory they need, when they need it, and not have to worry about running short or not having space to store excess material.
Suppliers offer the lowest amount of risk related to inventory levels, since they themselves have healthy levels of material on-hand and have a network of mills from which they purchase. If one mill delays an order, suppliers can turn to other mills for the material.
Retailers also offer low inventory risk, but have less demand visibility than suppliers (who often sell a bulk of their orders via contract, and can predict demand). For this reason, retailers have higher inventory depletion risk than suppliers.
Purchasing through mills comes with a lot of inventory risk. Buyers typically must buy larger loads of material and store the material until depleted. This requires ample storage facilities and the ability to move and manage steel plate (i.e. overhead magnetic cranes).
Additionally, mills are more at risk of running behind in production. These delays in inventory could leave a buyer scrambling to find material to bridge the gap between depletion and the next mill delivery.
Retailers, suppliers and mills each offer different methods for buying steel plate, and it is important to consider which method best suits your order needs and which source is able to accommodate those needs.
Retailers offer the most buying methods, with the option to purchase steel plate in-person, on a website or over the phone. This gives buyers great flexibility in how they can purchase plate materials. However, buying from a retailer tends to be more impersonal, so they may not be able to accommodate special requests for less common grades or extensive processing.
Suppliers traditionally take steel plate orders through direct communication with a sales representative. But some – like Leeco – also offer the option to buy through an ecommerce website. Flexibility in how orders are placed allows buyers to customize the purchasing process based on their requirements. Buyers with simpler needs who are looking to quickly order a popular plate grade can opt to buy online, while buyers with more complex, specific needs can work directly with an experienced sales representative.
Mills offer the least flexibility in buying options, as they typically take orders via phone or email with a sales representative. Most mills due not offer the option to buy steel plate online.
With each steel plate supply source, there are strengths and trade-offs. Determining how important each factor is for you – as well as any other factors important to your business – will help guide you towards the right steel plate supply source.
Leeco® Steel is the largest supplier of steel plate in North America and services clients big and small with a wide range of volume and delivery needs. We would be happy to quote your next project and would be honored to be your steel plate supplier of choice. Submit an inquiry here.