Tuesday, October 4, 2011

Knife geekiness

Say you want to learn Japanese knife sharpening techniques.  Where do you go?  The only place I know of on this coast is Korin in New York.  That is a bit inconvenient for me at the moment so I thought of a better place -- Google.  I don't mean the search engine (though that was very helpful too), I mean the Google office in Cambridge, MA.  That office probably offers the highest concentration of geekiness in the Metro Boston area and this characteristic seems to be very highly correlated with people's obsession over their knives.  Google also happens to be the work place of Scott McKay who has an extensive Japanese Knife Collection.  I don't mean the stuff you buy at William and Sonoma.  I mean serious stuff.  Some of it is so serious, it has never touched a cutting board.  You wouldn't want to cook with a museum quality knife, would you?  But there are many lovely Japanese knives that Scott does use for cooking and thus needs to maintain.

I've met Scott at the Culinary Historians of Boston many years ago, and decided to contact him with a plea for sharpening help.  Scott gladly agreed and told me to come with my knives, tomatoes, and onions.  I also brought band-aids.  After reading Matthew Amster-Burton's article, I figured there was no way I was getting out of this experience without some blood.  Scott brought his knife collection and a few sharpening stones.  

I was learning to hone a knife on a stone since that's preferable to a rod (a.k.a. steel) for Japanese knives.  First we had to find the right angle.  To do that, Scott told me to set the knife flat on the stone, put the fingers right on the edge and gradually lift the back of the knife until there was no gap between the edge and the stone.  To maintain the angle, I had to keep my fingers right on the edge as I pushed the knife forward and backwards on the stone.  It was actually quite easy, except for not cutting myself.  I walked away from this experience unscathed, but I was cheating a little.  I put my fingers right on the edge to find it while the knife was stationary, but when I started pushing the knife on the stone, I moved my fingers a little back.  

After practicing for 20 minutes I felt pretty good about the process.  Did the knife get sharper?  Not that I noticed, but I've only used the Mac (Jason's birthday present to me) for 1 week, so it was very sharp to begin with.  The good news was that I hadn't made it duller, which could easily happen if I was not using the stone correctly.  

After I got home, I was so inspired that I pulled out my cheapy Norton stone and used a similar technique to what Scott showed me with some tips from Chad Ward's wonderful egullet post to give my Forschner a more narrow angle.  One thing I did differently this time is I sprayed the stone periodically with water.  I realize it's an oil stone, but oil seems too messy and slows down the sharpening process a lot since it reduces friction.  The few times I used the stone before, I tried it dry since Cook's Illustrated said it worked fine dry.  But that metal slurry the knife forms on the stone when the water is added really seemed to help.  

I was aiming for 15 degrees.  With a little trig I was able to figure out how high I should lift the back of the knife given its width and the angle that I wanted.  I don't think I've used a sine function in over 12 years.  It was kind of fun to use high-school math again.  The edge came out quite nice.  

This is not a minimalist dish from a molecular gastronomy establishment.  It's my sharpening test.  One grape tomato was sliced with a Forschner and one with a Mac.  Can you tell which knife was used for which row?  If I can make 1mm slices of tomato, I think my knives are in working order.  Onions still feel a bit harder for a Forschner, but I am guessing that's just the geometry of the knife.  The Japanese knife is thinner, so cutting takes less effort.   Now if only I could have the Mac blade with a Forschner handle, I'd be in heaven.  

Now that my Japanese stone has arrived, I was able to give both my Mac and Forschner a much more polished edge.  The Japanese stones are much smoother than western.  The one I got is 1000 grit for the coarse side and 4000 for the fine.  My Norton stone isn't labelled, but I am guessing it's 300 for the coarse and 800 for the fine.  

I have also finally learned to use the steel correctly.  Yes, everyone goes swishing their knives on it, but does it do anything?  After replacing my worn out steel with a new one (sharpening tools wear out too!), reading Chad Ward's post, and watching Patti Small from On the Edge Knife Sharpening do it a few times in person, I finally got it.  The angle should be just a little wider than the angle of the edge and the pressure should be very light.  Since I have so many Forschner knives, I took one to Patti for a 15 degree edge.  She has an EdgePro system that controls the angle perfectly.  This is my example knife against which I can compare my free hand sharpening efforts.  

Now I feel kind of bad feeding the rest of my knives to that Chef's Choice electric machine or using AccuSharp.  The truth is, they work.  They give your knives a rather wide angle of 20-22 degrees and chef's choice leaves occasional very small bumps in the edge.  But they don't take any practice to master and are a lot faster than stone honing when I have to deal with 15 knives I use for classes.  They are also a great option for people who are not that obsessive about knives but want to be able to slice a tomato cleanly.

But for my own knives, I'll try to keep practicing free-hand sharpening and honing.  If I keep this up, maybe I'll buy myself a really nice knife.  About 15 percent of my students show up with Shun and Global knives these days and have no idea how to maintain them.  Most of these companies will resharpen your knives for you if you send them back to them, but that's like deciding to have children and thinking you'll call a baby-sitter when the diapers will need to be changed.  If you want to have kids, you'd better learn to change diapers.  And if you want really nice knives, you'd better get up close and personal with a stone.  


Julia said...

Hi Helen, I have a question inspired by your thinly sliced tomatoes. When I cut tomatoes, I find it much easier to slice them thin when I use the tip of my knife rather than the back of it. However, this is at odds with what your knife tutorial videos tell me to do.

so, how do you slice tomatoes to make them consistently thin?

Helen said...

Tomato is a weird beast. You need to glide the knife along the skin rather than push it down. You can start in whatever part of the knife you are comfortable in, but realize that for a clean cut you should probably use most of the blade. I usually start around the middle of the blade and glide the knife away from me. If you want even more of a glide, start at the tip. Another difference is that I don't keep the tip of the knife on the board when working with tomatoes. I lift the whole knife to reduce the pressure on tomato, but make sure the tip lands on the board before the back does.

Since you don't need much speed with tomatoes, using this slightly less efficient way is not a biggie.

But if you feel that you need to pierce the skin with the tip of the knife, that's not good. This means you should sharpen your knife. Any part of the knife should get through the skin with no pressure.


Julia said...

Helen, how did you decide which sharpening stone to buy? can you recommend a good resource that reviews different sharpening stones?

Helen said...

Hi Julia,

I asked Scott, who taught me to use the stone, which one to buy. I link to the one I bought in the post. But keep in mind that you can cause a LOT of damage if you do it wrong (both to the knife and to the stone).

How do you hone and sharpen your knives now? What brand of knives do you use?

Before you go anywhere near a stone, I suggest getting a ceramic rod ("steel") and learning to use that correctly. Even if you have Japanese knives, it will work fine and is a lot easier and safer to learn. It will also cost a lot less :)