HOME > Chowhound > Cookware >


Discolored blade on new Shun knife

I just got a new Shun Classic chef's knife a less than a week ago. It's been lightly used several times, then washed, dried and put into a knife block after each use. It has not sat with any food on it, it has not sat in water, nor left wet. Obviously in a week it's seen very light usage. Tonight, though, I noticed that it has a cloudy bluish-grey "stain" on the blade on both sides. Looks like a water mark. I've carefully cleaned it once more with dishwashing liquid and a soft sponge just to make sure it was well-cleaned, but it's still there.

I've never seen this even with my cheaper, abused knives. Is this a defect and should I return it? Do these blades need some special handling that Global doesn't need?

  1. Click to Upload a photo (10 MB limit)
  1. I would guess your knife has a high carbon steel content. Knives with a higher carbon content are generally more susceptible to staining from acidic foods.
    Global knives are stainless steel. It may help if you let others know which series of Shun you have. Ken Onion, Pro 2?

    1. A soft cloth or sponge and a little Bar Keepers Friend should take care of that.

      3 Replies
      1. re: jeffreyem

        But remember that it will leave slight scratch marks on your blade. As long as that's ok, I would agree w/ the Bar Keepers friend.

        1. re: sandih

          Does this "stain" look like moire, the cloth we used to call "watered silk"? Because if it does, that's the knife itself, its distinctive appearance. It's done (they claim) by the old process by which samurai swords were made, and it's what drew me to the knife in the first place. I absolutely love it! And its appearance is part of that, the blade doesn't look like any other knife.

        2. It shouldn't be discoloring. It does have a distinctive pattern as mentioned so that might be what you're noticing.

          The bluing might also be oxidation and could be a sign of future rust. A Shun, cared for properly, shouldn't rust. So there may be a defect in there.

          The retailer will receive a free credit from Shun so if you are unhappy with it do not be afraid to take it back and exchange it for another. If you bought it from a reputable retailer or knife dealer they should also be able to tell you by looking at it if what you're seeing is normal for the knife or not.

          1. The Shun knife is a stainless blade so I wouldn't expect a patina as described. That is exactly what I would want to see on my carbon steel knives or on the edge of a carbon steel clad in stainless with a carbon edge. For most stainless I would still recommend cleaning and drying a knife as soon as you are done with it. Just makes for good care habits.

            2 Replies
            1. re: scubadoo97

              I don't own a Shun but the Ken onions appear to be high carbon and of a damascus style pattern like BerkshireTsarina is describing. If they are high carbon then they are probably not Stainless. Staining from acidic foods should be expected. Shun like most knife makers offers several lines each of a different type of steel.

              1. re: Docsknotinn

                True. The majority of Shuns I've seen are stainless with a Damascus finish.

                On the Kershaw website Ken Onions are listed as VG-10 which is stainless with 32 layers(16 layers on each side) of SUS410 stainless. The Classic that the OP stated is made of the same construction as the KO. The Alton Brown is also the same material

                They do list other steels like SG-2 Powdered Steel on their Elite line but it too is clad in 410A stainless but it may not be at the edge.

            2. It's from the Shun Classic line (sold at Williams-Sonoma). The discoloration is not the damascus blade, it's a distinctive blue-grey "haze" on both sides of the blade. It's a week old today, and has been washed and dried as soon as it's been used (no, not put in the dishwasher, either), so it's not user error as far as I can tell.

              From the Shun/Kai site (http://www.kershawknives.com/productd...), the blade is:

              - VG-10 stainless steel is clad with 16 layers of SUS410 high-carbon steel on each side, producing a 33-layer rust-free Damascus look
              - VG-10 "super steel" is composed of Carbon, Chromium, Cobalt, Manganese, Molybdenum, Silicon, and Vanadium

              It claims to be rust-free. I do think I will exchange it. I got it as part of a 10-piece set as a gift from my husband, so I want to ease his mind that he bought quality and that this is a fluke. If this is part of the aging process and its to be expected, that's OK, too. I just want to be sure. But should it really happen in less than a week?

              ETA: Whatever it was cleaned right up with Barkeeer's Friend - hanks for the suggestion!

              4 Replies
              1. re: Divamac

                I found Shun's customer service to be great. When Sur la Table refused to sharpen my 3 Shun knives I (eventually) sent them to Shun for sharpening. They were, admittedly, pretty chewed up by them, being my first "good" knives and relatively delicate on the edge.

                Shun sent me back 3 brand-new knives. No questions.

                1. re: cyberroo

                  Sur La Table shouldn't have refused to sharpen your knives, that's little extreme. What they should have done, however, was tell you that their sharpening machine would put a "European" angle on it, e.g. something around 20-22* rather than the 15-16* it should have.

                  To the OP, my Shun did the same thing too -- make sure it is completely dry before putting it back in the block. Wash with nice hot water (not too hot), towel dry it, then leave it on the counter to air dry for a few minutes. I usually get those if I wash them and forget to dry the blade and the water dries on the blade. Enjoy your Shun!

                  1. re: mateo21

                    The sur la table closest to me does sharpening but they just use the chefs choice electric sharpener.. nothing you couldn't pick up yourself.. 15/20

                    1. re: grnidkjun

                      That is weird. They just stick your knives into a home electric sharpener?

              2. Hi Divamac,

                Yes, this sounds weird for a Shun Knife. I'd contact Shun directly and see what they think the cause is. More than likely they'll offer a sound solution. Their customer service is outstanding and top-notch.

                Hope this helps!


                1. I work for a knife shop and I have to say i know alot about the shun line. We have had some people with the same problem, Docsknotinn is correct for the most part, if any acid or liquid is on the blade u need to wash it off very well with soap and water and a scrub brush to prevent that. Unfortunatly shuns warrenty doesnt cover that cuz its considered miss use or abuse :( U can clean it off with non abracive cleaner like Flitz. Hope that helps

                  2 Replies
                  1. re: titan1701

                    One thing people need to remember is stainless means it stains LESS. Does not mean stain proof.

                    1. re: scubadoo97


                      Unfortunately, there is a correlation that higher carbon steels tend to be not more prone to rust and stain. A really really stain-proof steel tends to be weak.

                  2. Same thing happens to my Global chef's knife every now and then. I notice a kind of a bluish rainbow tinge on the working part of the blade. It comes right off with a bit of cleanser. Moisten a tissue, put a drop or two of cleanser on the tissue, and rub gently. No stains, no scratches. (I've used both Fissler Stainless Steel Cleaner and Kleen King Stainless Steel and Copper Cleaner with equal success.)

                    8 Replies
                    1. re: tanuki soup

                      I have had most of my knives for over 10 years and I have never had to care for them in any of these crazy ways. If I pay over $100 bucks for a chefs knife it better be friggin impervious to battery acid. Shun's look pretty but if I have to be worried about what I cut with it and when and how I apply soap and water then forget it.

                      1. re: mainecoastchef

                        Better stick with those Forshners and Dexter Russels Chef.

                        1. re: mainecoastchef

                          I am the OP. I posted the following day (20 months ago) that my Shun cleaned up effortlessly with a bit of Barkeeper's Friend (which is always in my kitchen to clean my pots and SS sink) and staining has never been a problem since. If you want a less expensive knife, go for it. But I wouldn't trade my Shuns for anything. I use them daily and they are as good as the day I bought them - no special care required. My Global knife is also pretty indestructible.

                          1. re: Divamac

                            Yes, Bar Keeper's Friend can remove stain and rust from a stainless steel. I won't say it is perfect for these jobs, but it can do it. However, as mentioned before, there is often a trade-off between high quality sharp knives and corrosion proof knives. For example, Shun VG-10 can hold a very sharp edge for a long period of time. The vanadium in VG-10, where the "V" stands for, allows the steel to take on a fine grained carbides. Consequently, the Shun knives can sharpened to a very fine edge. but it is on the lower end of stain/corrosion resistant in the stainless family. On the other hand, 420 is very stainless. It is often made to be a diving knife because is extremely stainless even under sea salt water. However, a 420 knife cannot take on a sharp edge.

                            In general, it is better to have a sharper knife because it is such a pleasure to work with and the extra time to wiping it dry is all worth. A Shun knife is still extremely maintenance free when compared to pure carbon steel knives, which are the top choice for Japanese chefs.

                            1. re: Divamac

                              LOL, you tell 'em, Divamac! I was wondering why this thread was resurrected from August 2008?!? People are just too funny.... :-D

                              1. re: Eiron

                                nothing wrong with a thread being resurrected as it may help someone today with a problem similar to the OP.

                                1. re: scubadoo97

                                  No, I agree, nothing wrong with that & yes, it can help. It was just that, in this case, the renewal came about from a (very) late suggestion to a long-resolved question.

                            2. re: mainecoastchef

                              Actually, the more you the pay, the more likely your knife will stain.