Undesirable food reactionn with carbon steels

[Fedusa]

I recently swapped all my knives for carbon and have a White #2 petty that I cut a mango with today and it smelled terrible.
It was a mix of wet dog/cat food, even the mango juice off the blade had that same off taste. Mango itself was delicious and left no bad smells thankfully.

Anyone else experience this? Its particularly noticeable with this petty though, quite a few reactive foods leave off smells. It's got a bit of patina already but will this stop and settle down more as the patina evens or will it always do this?

 

[Drosophil]

It's most likely not the core steel, but the soft steel in the cladding, which is a lot more reactive. It will usually tone down once more patina settles, but some will still stay a bit reactive (older Tanakas and Shiro Kamos, for example). Wipe the blade often during use, don't use abrasives when you wash it (so you protect the patina) and it shouldn't be a problem.

 

[krx927]

This is quite normal for carbon knives. Like said you need to build the patina and this issue will completely dissapear. Best way is to force the patina and you will immediately solve the issue. I like to build the patina with cooked chicken (slightly undercoocked). Cut the chicken with your knives and then leave them for 5-10 mins then clean. Repeat a few times and you will get beautiful blue patina that will completely fix your problem of reactivity.

 

[alterwisser]

Yeah, acidic fruits (not sure how acidic mango is) are probably not your best choice to use a brand new carbon knife on. I'd stick to certain veggies (zucchini, eggplant), mushrooms and protein at first. Then slowly you can use it for more acidic foods. I personally don't use carbon on any fruits, but mostly because I'm cutting fruit at the dinner table and don't want to run back to the kitchen to clean it

 

[Benuser]

This is quite normal for carbon knives. Like said you need to build the patina and this issue will completely dissapear. Best way is to force the patina and you will immediately solve the issue. I like to build the patina with cooked chicken (slightly undercoocked). Cut the chicken with your knives and then leave them for 5-10 mins then clean. Repeat a few times and you will get beautiful blue patina that will completely fix your problem of reactivity.

Please clean the very edge immediately, though, e.g. by cutting lightly into a cork, or it will dull.

 

[Chef Doom]

I'm going to give you some better advice than the "deal with it" campaign.

Buy yourself another stainless or semi-stainless knife for acidic fruits. Call it your mango knife for kicks.

 

[Mute-on]

Agree with Chef Doom. I made the mistake of using a clean White 1 mono (Sakai Yusuke) on lemons and it created a pretty nasty reaction which left a smelly and slightly rough and "grabby" patina, no longer a smooth surface.

Solution was to rub down the blade with a paste of baking soda to restore the finish, and use a stainless knife for acidic fruits.

The Yusuke is amazing for butternut pumpkin and potatoes, though

 

[Fedusa]

Hmm, I do have a few stainless knives but good to know to avoid acidic foods with it, will try again when it has a better patina.

I haven't had much time to cook lately and wanted to get some use out of the carbon knives but lesson learned!

 

[mikaelsan]

If it's an option and the secondary edge looks a bit rough I would polish that out (if it's a ku), then let a patina set in, I don't know if it's universally true but it made a quite noticeable difference on my Nakiri

 

[HRC_64]

I'm going to give you some better advice than the "deal with it" campaign.

Buy yourself another stainless or semi-stainless knife for acidic fruits. Call it your mango knife for kicks.

+1

Not always an endless supply of towels or access to water or socially appropriate
to be fussing with the knife (table service).

 

[Chef Doom]

Hmm, I do have a few stainless knives but good to know to avoid acidic foods with it, will try again when it has a better patina.

I haven't had much time to cook lately and wanted to get some use out of the carbon knives but lesson learned!

Some carbons will react less after a patina builds up. Some never will. You could cut low acidic fruits like apples or pears to see how strong the reaction is in comparison but to be honest there is need to suffer nowadays. It's 2017.

 

[krx927]

Please clean the very edge immediately, though, e.g. by cutting lightly into a cork, or it will dull.

I always do this pre sharpening.

 

[Razor]

I mirror polished my White #1 Tojiro. I didn't like the mirror finish so I brought it down to 1200 grit (lengthwise scratches) and then soaked it in hot vinegar for 15 minutes. It seemed to work well. Not the natural patina that can only come with time but an immediate result. Blue and gold soft matt finish that is not reactive at all. The core steel did turn black but was easily wiped clean with a rag. Re-sharpened and I like it.

 

[Chef Doom]

He can try that method if he wants and it could work but some carbon steels will react regardless of forcing a patina.

 

[ob-gym]

Frequent rinsing while you build patina will help, the acid from fruits sitting on your patina will slowly eat it away. Similar concept to removing patina with Barkeeper's Friend, which is basically oxalic acid.

Make a few cuts, rinse, wipe, and repeat. Should make your patina much more resistant

 

[Chef Doom]

Frequently rinsing a knife while cutting mangos sounds about as practical as thinning a kocki with a 6000 grit stone.

 

[Chef Doom]

I meant *kochi

 

[Bodine]

Or he could just buy a Kochi, mine will cut anything acid with no adverse affects.

 

[toddnmd]

Frequently rinsing a knife while cutting mangos sounds about as practical as thinning a kocki with a 6000 grit stone.

I think the point of that post was that rinsing was a short-term suggestion while building patina, rather than a long-term usage pattern. Of course there are other ways to build patina, but initially using and rinsing has worked well for me in establishing a patina.

 

[Chef Doom]

The point was understood but people in general have a habit of

1. Giving people unrealistic advise (for various reasons)

2. Giving advice that they themselves do not follow.

The point I was making was just because something is possible doesn't make it practacle.