It’s quite time consuming as you have to do each serration individually with the steel rather than running it along the length of the blade as you would do with unserrated knives but it is possible to do it yourself.
You need to run the steel two or three times into each serration in the same direction every time then run it a couple of times down the flat side of the knife.
They don’t need sharpening as often as regular flat knives so it’s not too onerous to do it every now and again.
OH sharpens most of his knives himself, but the bread knives, pinking shears and a few other special pieces, oddments and whimsies go to Elsner. They are very good.
These are probably the stainless steel type bread knives with a serrated edge. Normally these cannot be sharpened satisfactorily. It is best to adapt your bread purchasing to match the sharpness of the blade. When the knife is new you can buy "Basler Brot" and similar breads which have a thick, hard crust. Towards the end of the life of the knife you should choose softer breads like "Tessiner Zopf". When the knife has even problems with "Tessiner Zopf", then simply replace it.
you can still sharpen these using the edge of a whetstone by holding diagonally the knife and sharpening 4 times to cover 2 sides and 2 directions of the ridges.
I know all the professional advice says not to do this, as it changes the angle of the serrations and eventually wears them down completely, but as I see it:
- it wears down the serrations less quickly than badly sharpening the serrated side
- it's a bread knife not a surgical tool, it will still cut bread
If you prefer to eat stale bread, which can become very hard after a few days, it may be that a conventional bread knife is not the best tool for the job. Maybe something like this will last a bit longer and, anyway, you can simply replace the blade if it becomes blunt.