Carbon steel knife care/maintenance

If you cut lots of lemons and onions, you should plan to spend the first couple of weeks with a slightly damp towel and a very dry one within immediate reach. Every time you finish cutting something like this, wipe well with the damp towel, and if you are pausing for even a minute or so follow up with the dry. After a time, the knife should develop a distinct dull-gray-blue patina. Until it does so, some of your first slices of acidic foods are going do discolor fast if you don't do something about it -- this is particularly true of onions. So you may want to have a bowl of cold water to dump your cut onions into, which will rinse off the weirdness fast.

One great solution is to do something like make French onion soup, or set up your prep station to break down a huge mass of onions all in one go. Make sure you've already started the patina -- cutting almost anything for a day or two will do that. Then just wade into your onions, wiping damp often as you go. By the end of the shift (or task, if this is at home), your knife will be very far along the way to a great patina that will not react with onions and lemons in the future.

 

At first, yes, the onions will discolor and possibly smell funny if you don't drop them in water. How much, and how strongly it smells, depends enormously on the knife. But this effect goes away quite quickly -- especially with the quantities you're going to be cutting. Just don't freak out when, after a single day of onion prep, the knife looks much different from the way it did when you got it.

Some steels will take a continual light polish, no matter what they cut, and will develop a very light misty-gray color. I personally have only seen this in fairly high-end usuba, but then I don't have the widest experience. Most people don't try to maintain a constant polish on a gyuto anyway, so you just let it dull to where it wants to go. My Masamoto KS-3127, for example, quickly takes on a strangely attractive dull color that to my eye says, "I am evil and wish to do dreadful things to foods. Let's go play." It's what some people seem to see in certain motorcycles, though I can't much identify with that one. By contrast, my Aritsugu usuba and my unnamed blue-steel yanagiba (long story, but it's medium high-end) simply have a faint not-quite-shiny thing that says, "I have a sufficient patina, so don't worry about it." And then there are people who use mustard and stuff to force a really deep blue-gray patina.

I can't speak to the knife you're going to be using, but I do think that for the first day or two of heavy service, you're going to need to assume that anything strongly acidic may not only affect but be affected by the knife, and work around that.

 

After slicing acidic foods or any foods for that matter, I briefly rinse and then dry the blade.

When sharpening using my Norton stones, I spray them with water and not oil as a "lubricant" that floats off the particles.  Using water, I get a much sharper edge and achieve it more quickly than with oil.

If you insist on using oil for your stones, go to a tack and feed store (horse supply) and get yourself a gallon of mineral oil because it'll cost less than $15.  Don't bother with the commercial products labeled as honing oil since their usually mineral oil rebadged.

 

You'll smell the food reacting with the steel, not just the steel.  In the case of onions the smell will be somewhat sulphrous; in the case of meat, somewhat coppery; etc.  I suggest rubbing the knife down with a baking soda paste before each shift for the first week or so, whether or not you're ultimately going to force a patina.  That will keep the stink down significantly.

This whole thing may be a red herring with me reacting to kokopuff's advice, but... Don't bother using oil stones on a Misono Sweden, whether dry, with water or with oil.  They're too slow.  Furthermore, I own and use Norton India stones for a lot of different knives, but neither they nor Crystolons will not give you anywhere near the finish a Sweden should have.  I forget (or never knew) where we stand vis a vis your knowledge of water stone lore, but if you don't know which stones are appropriate for you, your level of expertise, your budget and your Sweden, just ask.

So many commas, so little time,

BDL

 

I have no idea how your beautiful Misono carbon knife will react to acidic food.

But, the main reason why carbon knives aren't my favorites happened when I cut 3 pine-apples to make jam with a carbon knife. Unbelievable how fast and violent the acidity from these fruits react with the steel! It stinks, a lot! You also need to know I just mirror-polished that thing!

Couldn't be plain oxidation or the blade would show rust. Instead it showed most of the rainbow colors. Luckily enough the knife doesn't react all that much when cutting meat, the purpose I bought the knife for.


 

 

 

By the way, this is how the knife looked like after polishing for many hours... a week before I did the pine-apple jam!

 

@BDL:  I was referring to older carbon steel and not some newly manufactured Misono knife.  I also find that my India stones perform their tasks much more quickly by using water instead of oil as the liquid of choice.

And based on the few photos I've perused of the Misono Sweden, I see no surface pitting on that blade and therefore I'm led to believe its metallurgy differs from the that of the older Sabatiers that I own.

And funny, I never noticed any off odors from my old Sabatier after cutting most any acidic food including fruit.  And to blazes with the mirror finish: it doesn't work for me.

 

Carbon Sabatiers can take, hold and benefit from a finer grit than a fine India.  They're in that happy group of knives which sharpen almost equally well on oil stones and water stones; a "Surgical Black" or Translucent Arkansas make good finishers for them, and so do coticules if you want that much polish.  I sharpen mine -- and I have a bunch -- on Indias, Arks, a variety of water stones, and a variety of strops and stropping compound.  They take such a great edge so easily it almost isn't fair.

A Misono Sweden gets just as sharp and certainly holds the edge better.  It just can't compete with Sabatier's profiles -- that takes a Masamoto.

The idea of using any liquid is not to lubricate the stone but to float the swarf and keep the stone from clogging.  Oil, the most viscous of the good liquids does that best, but unfortunately it also slows the process the most.  And ultimately the oil/swarf mix works its way into the stone's pores and is very difficult to clean -- making the stone very slow indeed. 

In my experience, sharpening dry on (nearly all) oil stones (specifically including but not limited to Norton India stones) works even better than water, which works better than soapy water, which works better than oil.  You'll have to clean your stones more frequently, but since the dishwasher does most of the work... 

However, it's something of a red herring since no one suggested sharpening on oil.  Or, did they?

BDL

 

BDL:  when I transitioned my stones from oil to water, I soaked them for 2 to 4 months in kerosene to relieve them of their previous oil treatments as it were.  In your opinion, would it still be okay to clean them in the dishwasher without there being any residual oil odor or oil film coating the dishwasher?  In the dishwasher, do you also use dishsoap for cleaning the stones?  Do you place the stones in the dishwasher along with other kitchen plates and utensils?

 

In the dishwasher with soap and everything else.  Sometimes it takes more than one ride.  In extremis or as an alternative they may be boiled in water with a little dishwasher detergent in a non-reactive pot for ten minutes or so. 

If the stones are very dirty, they might need to be scoured with scouring powder and a brass bristled brush before washing.  I do this routinely. 

If the stones are old and stained and the combination of scouring, the dishwasher leaves them clean but still looking dirty, and you care, try rubbing them with Mr. Clean Magic Eraser.  I like to keep my stones pretty clean as a check on their effectiveness.  Clean stones are faster and scratch less.

You can also scour with mineral spirits or kerosene to remove staining, but must wash the stones very thoroughly after.

BDL

 

Niiice reply!

 

Interesting threat, and what I like the best is that there is no name-calling or other insulting here!