Stainless Steel: All About Food Grade 304, 18/8 and 18/10
What's the difference between the different grades of stainless steel (304, 430, 220, etc.)? What do the different numbers mean (18/8, 18/10, 18/0, etc.)?
The "grade" of stainless steel refers to its quality, durability and temperature resistance. The numbers (18/8, 18/10, etc.) are the composition of the stainless steel and refer to the amount of chromium and nickel (respectively) in the product.
So, what do the numbers mean?
18/8 and 18/10: These are the two most common grades of stainless steel used for food preparation and dining, also known as Type 304 (304 Grade) and are part of the 300 series. The first number,18, refers to the amount of chromium present and the second represents the amount of nickel. For example, 18/8 stainless steel is comprised of 18% chromium and 8% nickel.
304-grade stainless steel is also comprised of no more than 0.8% carbon and at least 50% iron. The chromium binds oxygen to the surface of the product to protect the iron from oxidation (rust). Nickel also enhances the corrosion resistance of stainless steel. Therefore, the higher the nickel content, the more resistant the stainless steel is to corrosion.
18/0 - Contains a negligible amount of nickel (0.75%) and therefore has a reduced corrosion resistance (is more likely to rust than 18/8 or 18/10 but still high quality) 18/0 is also referred to as Type 430, is part of the 400 series and, unlike 300 series stainless steel, is magnetic.
200 series: You may often find stainless steel food containers made from 200 series stainless steel. These are typically less expensive than 304 grade as manufacturers essentially substitute manganese for a nickel. Although food safe, they are not as resistant to corrosion and not as high quality as 304 grade.
Is stainless steel safe?
Stainless steel is one of the most common materials found in kitchens today. It's used in everything from appliances to cookware, dishware, flatware, and utensils because it is durable, easy to sanitize and corrosion resistant to various acids found in meats, milk, fruits, and vegetables. Most importantly though, stainless steel is a safe option when it comes to use with food and beverage, as there are no chemicals that can migrate into your food from these products.
Stainless steel, glass, cast iron, wood, ceramics with lead-free glaze and bamboo are believe to be the safest materials to use in the kitchen.