We solve the cryptic 18/8 and 18/10 codes often seen on marketing materials for stainless steel water bottles in this Q&A
Q: I saw that some water bottles are made of 18/8 stainless steel, while others are 18/10. What is the difference between 18/8 and 18/10 stainless steel? Which is better?
A: Before answering the question, let us first understand what exactly is stainless steel.
To qualify a metal as 'stainless steel', it must satisfy the following conditions:
- Contains steel, which itself is made of mostly iron with a carbon content between 0.2% and 2.1%.
- Contains at least 10.5% of chromium, which makes stainless steel resistant to staining, rusting and corrosion.
But metal manufacturers may also add additional elements such as nickel, molybdenum and manganese, or increase the amount of chromium in the basic recipe for stainless steel to achieve specific properties that they want. That's why you can find more than 100 different types of stainless steel being used for a wide range of purpose.
18/8 versus 18/10 Stainless Steel Bottles
Now, let's decipher what do 18/8 and 18/10 mean.
The first number actually refers to the percentage of chromium in the stainless steel, while the second number indicates the amount of nickel.
So, 18/8 means that 18% chromium and 8% nickel have been used in the production of the stainless steel. You can probably guess what's in 18/10. That's right, 18% chromium and 10% nickel!
Does the extra 2% of nickel matter? Yes, it seems. First of all, extra nickel enhance the corrosion resistant of the metal to acidic and alkaline solutions. So a stainless steel graded 18/10 is more corrosion hardy than one that is 18/8.
Secondly, extra nickel also means higher cost. It may not be a lot for one stainless steel bottle, but when you think in terms of tens of thousands of bottles, the extra few cents can add up to quite a lot.
Having stated the differences, note that in terms of strength and weight, there is virtually no difference between the two grades of stainless steel.
Besides, when you are comparing stainless steel bottles, the grade of stainless steel used shouldn't be the only factor in mind.
The thickness of the metal which will affect the durability and its resistance to knocks and falls, the reputation of the company, the warranty given, the design and how user friendly is the bottle, as well as how attractive the bottle looks are also some factors you should consider.
You can get a 18/10 stainless steel bottle, but if it leaks whenever it's not in an upright position, then you're going to have nightmares using it no matter how corrosion resistant the bottle may be.
But if everything being the same, I'd say go for a stainless steel bottle that is made of 18/10.
Have fun shopping!