A question about carbon steel knives

Friends have just returned from Japan with some stunning knives, one of which is carbon steel. After the first use, however, this knife has become stained and discoloured (rust?). Can anyone help with some advice on how to restore the knife, and how to properly maintain it?

I've also mentioned to my friend that the best way to maintain the edge on his knife if by cutting on wood rather than plastic. He's bought a stone, but should he use a steel regularly, and grind on the stone occasionally to put the edge back on? Or use the stone more frequently?

Thanks in advance!

Celia

We have three carbon steel knives that we use regularly. Immediately after use we clean them with a sponge that has Scotch Guard on one side (being careful not to hit the knife edge), and dry and put away. If you don’t dry right away, they will rust! The Scotch Guard with soap will take the stains out, at least most of them. They will always be somewhat stained, and never look like stainless steel.

What Carl says. "Good" carbon steel is the standard for holding an edge - the best stainiess is maybe almost about as good. Steel and stone as you would for a good stainless knife. You can polish the surfaces with #0 or #000 3M plastic fake steel wool - it really works well and it's cheaper than ScotchBrite. -- I think the #0 is the same as the light-duty Scotch-Brite, but no soap in it.

John

"Stunning" carbon-steel knives from Japan, the ones with the layered soft-hard-soft steel, are very special indeed, and do require some special care. I would not recommend the use of a steel, which is really more about pushing a softer steel edge back into line than anything do to with true sharpening; I don't find steels that effective or useful for harder knives. Ideally, you would use natural waterstones to keep the knives sharp, but you can certainly do very well with artificial waterstones or diamond stones (I do not recommend the diamond stones that have a pattern of holes). One in 800 grit and one in 1200-2000 grit would be a good working set; a 6000 grit stone (plus the requisite nagura stone to raise paste on the 6000 grit stone, except in case of diamond) would get you the finest edge that these knives can muster, which is likely to be amazingly sharp. You can obtain such stones from online woodworking suppliers like The Japan Woodworker; if you're interested in the natural stones, there's a guy on eBay selling them directly from Japan for much more reasonable prices than the woodworking shops have. His listings are overwhelming in their complexity, but the stones I've gotten from him are great.

As for avoiding rust, the best thing to do is, yes, to dry thoroughly before stowing, but also to keep a thin coat of camelia oil or mineral oil on the knife. Even so, it is quite a challenge to keep these knives from discoloring somewhat, so I wouldn't worry about dark patches. Actual rust, you can take off with a scotch pad or "rust eraser," being extremely careful not to cut yourself.

Even before I moved to Japan I had several carbon steel japanese knives. I plan on buying a few more while I am living here.

Agree with comments to wash and dry thoughouly as soon as you are done using the knife. Even then the knives will take on a patina, the color will depend upon what you cut. The knife I use for boning has hardly discolored, but the one I use when cutting things like onions and citrus has obtained a wicked looking heliotrope color to the blade. It is the protective patina that your friends will want on their knives not the rust.

Most of my friends in the states who have known nothing but stainless steel are taken aback when they have seen the blades of my japanese knives. I have to explain that no they are not dirty, they are just not stainless steel.

Thank you all! I'll pass this info onto my friend.

Cheers, Celia

What Bryan said. Scrub it down and put a thin coat of oil on it.

I use a wine cork. I dip one end into some water and then some very fine grinding powder (like for grinding telescope mirrors or automotive use). After some rubbing on the blade, it's almost like new (you'll never remove all stains on a carbon-steel knife).

Thanks Larry and Chef. Larry, I'll pass on the grinding powder tip.

Larry, my friend just called and asked me to pass on his thanks - your suggestion worked a treat. His knife is now "almost like new", and he's dried it carefully and given it a thin coat of vegetable oil.

Glad to be of service.

I use a wine cork. I dip one end into some water and then some very fine grinding powder (like for grinding telescope mirrors or automotive use). After some rubbing on the blade, it's almost like new (you'll never remove all stains on a carbon-steel knife).

This. Not sure where dad learned it but the wine cork works well, plus, gives you a tad bit more clearance that a scrubby pad. I just use a scouring powder, but I like the grinding powder idea, Larry.

I use a wine cork. I dip one end into some water and then some very fine grinding powder (like for grinding telescope mirrors or automotive use). After some rubbing on the blade, it's almost like new (you'll never remove all stains on a carbon-steel knife).

I do the same as Larry. I use the cork as a fine sandpaper. I've even used a little Comet on the end of the cork and rubbed the knife's sides.

I never worry too much about appearance, just about function, although I suppose one would want to keep the new Japanese blades looking nice if possible.

I just stone the working blades I have in carbon steel (a boning and a regular chef's knife) and don't worry about appearance - oiling after use will certainly help, though.

Anyone have experience with Mac knives? I have a Wüsthof grand prix but it's not great with potatoes or hard larger veggies.

Drew

Drew - I've heard good things about them but the only direct experience is with a paring knife we have. It's a very good little knife.

We have an 8.5 inch Herter's (anyone remember them?) Chef's knife, a 5.75 inch Sabatier Mini Chef's knife, and a 6 inch Chicago Cultery boning/slicing knife. They are all over 40 years old, all are in great shape, and all are not pretty to look at.