Don't worry, I had to look up the meaning of hard anodised too when I sourced these beautiful kettles!
It is effectively a means of hardening aluminium, normally quite soft (try scratching your door liners; it's easy), and making it more hardwearing. It's a process involving baths of electrolytes and electric current but it means that hard anodised aluminium lasts longer.
Our hard anodised kettles are not perfectly non-stick but as it is not a coating but rather the actual body of the kettle it means that the nevertheless excellent properties that it does have will last a lifetime. It's very easy to wipe off spatters and splashes of other cooking from the kettles we sell.
