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Jun 14, 2012 07:44 PM

Lettuce Knife Prevents Browning Questions

I have a few questions about the lettuce knives. To those who do not know what I am talking, a lettuce knife refers to a hard plastic serrated knife specializes to cut lettuce.

For a long time, I simply assumed that a lettuce knife is made out of plastic for safety: sharp enough for lettuce, but gentle enough not to cut our hands.

However, a few week ago, I read a post on CHOWHOUND that a lettuce knife is made out of plastic in order to reduce the lettuce from oxidizing and browning. I then checked online and found out that "prevention of browning" is indeed a major selling point for the plastic serrated knives.

"The clear plastic blade will prevent lettuce from bruising or browning"

While I know carbon steel knives can induce oxidization of vegetables, I have not experienced stainless steel knives doing so.

So my questions to you are:

1) Do you have a plastic lettuce knife?

2) Do you believe that a plastic serrate knife reduces the lettuces from browning more so than a stainless steel knife?

3) If you do NOT believe the anti-browning property, then is there any major reason to own a lettuce knife?


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  1. I'll never own a lettuce knife.

    I don't remember the last time I cut lettuce. Well actually I do, but I've only cut lettuce in a restaurant that was used as a bed for something. I cut it immediately prior to using it. I've never actually had lettuce brown on me from cutting it, or from tearing it. I suppose if you cut it 24 hours before using it sure it might oxidize some, but it has never been a problem for me.

    I don't believe these knives, and I don't need another tool in my kitchen that is one tasked. I already own knives and am happier tearing my lettuce.

    1) no
    2) no
    3) no

    Often when I do cut lettuce, its more of a chiffonade of a couple leaves, so a plastic serrated knife is of little use to me.

    6 Replies
    1. re: TeRReT

      <I suppose if you cut it 24 hours before using it sure it might oxidize some>

      TeRReR. Thanks for your reply.

      True, but what you described is most likely the oxidization from the air. I wonder if the lettuce cut by a plastic knife will brown in 24 hours while lettuce cut by a stainless steel knife will brown in 4 hours (not real time, just an example). My guess is no, but I am curious to know other people's experience and answers. I believe your answer is also a no. Afterall, the "browning prevention" is a selling point for these knives.

      1. re: Chemicalkinetics

        Maybe a really dull metal knife could bruise and brown lettuce, but with a sharp knife I've never experienced browning. And if it isn't browning from the knife within 30-60 minutes I'd question that any browning that occurred after had anything to do with the knife and wasn't completely the oxidization from air.

        1. re: TeRReT

          By the way, I bought a US $6 Naniwa waterstone from H-Mart (Korean supermarket chain). I have not used it just yet, but $6 seems like such a great deal for a waterstone. The box states it is a 2000 grit, but inside there is a label of 1000 grit. It also feels like a 1000 stone. Finally, the website also states its part number is a 1000 grit stone.

          I very much wanted to post this on your previous post about a cheap knife and stone purchase in Japan, but I could not locate that post.

          1. re: Chemicalkinetics

            Yeah, I tend to wander off topic in threads so that post could be anywhere.

            Looks good though, even if it is 1000 grit thats a good price.

            My memory is working a little, my initial post would have been titled something along the lines of kochi knife but as I have 2 cheap stones I could have posted in 2 different places :P

            1. re: TeRReT

              That is ok. I just want to tell you about the stone. It would have been better to post the above waterstone entry to your previous post, but it is fine here. Afterall, you read it.

              Yeah, I really do not need the stone, but $5.99 was difficult to pass by. Almost all the waterstones on are at least $20. Most are around $30. There are cheap $3-6 oil stones. But this one is (looked to be) a waterstone at 1000 grit, a decent size (W x L x D) 2.5" x 8" x 1.25", made in Japan under the reputable Naniwa brand.

              I don't expect it to be as good as the higher end Naniwa stones, but if it works better than oil stones, then it will be a good buy for me. I used to tell people that all they need is to spend $20 for a waterstone. If this works, then I can say $6. :)

              1. re: TeRReT

                I played with the above Naniwa 1000 grit stone just a day or two ago. I sharpened my Watanabe stone with it and progressed to two naniwa super stone at 2000 and 5000 grit. This 1000 grit stone needs soaking just like any waterstone. It is very hard that sharpening on it did not produce significantly amount of mud, and it did not dish very much either. The stone seemed to cut/grind well though.

                I will try it a few more times. So far, it does not measure up to my other stones, but it is incredibly inexpensive.

      2. Chem,

        1. We have several, clear, orange and green.
        2.They are cheap and seem to work. (why, I do not know. But the edges don't brown as quickly)
        3. N/A

        2 Replies
        1. re: dcrb


          Really appreciated your input. Good to know. I don't eat enough lettuce salad to know, but if these knives really slow down the browning process, then it is pretty cool. I do know there is a huge difference between carbon steel knives and stainless steel knives. I could literally see certain vegetables like onions turn yellow/brown within 1-2 seconds when I use them using a fresh carbon steel knife.

          1. re: Chemicalkinetics

            I agree with the carbon steel; both blade and lettuce tarnish. I am not sure why these plastic knives work but for a buck or two at the grocery store, they were worth a try. Typically we will use one to halve a head of lettuce, use one and store the other. No brown for a couple of days but I have never really experimented to see how long this "miracle" lasts compared to cutting with steel versus just pulling a head apart with the hands. Might be interesting.

        2. I had one with a bit of curve to the blade which was bought for our sons to use when they were young, mainly for slicing pizza. It worked a treat, and they still have all their fingers!

          1. 1) no

            2) I believe oxidation is from cell damage, which is reduced by technique and using sharp knives, preferably as sharp as you can make them. Heck, my terribad German santuko can cut lettuce thin and not have the veg brown for a day. Imagine what a knife that's actually sharp could do!

            3) The health department is a pain in the butt?

            3 Replies
            1. re: shezmu

              This is a bit off-topic, but I'm responding to the unitasker comment. I have a plastic lettuce knife (ddn't buy it, it came free with a salad spinner or something). I don't cut lettuce often, and on those occasions haven't noticed that the plastic knife makes any difference. But it is excellent for cutting brownies and that sort of thing. Because it's plastic and not particularly sharp, it won't scratch a nonstick pan.

              1. re: Cliocooks

                When I was cooking in several places the owner NEVER allowed us to cut lettuce because of browning. We HAD to tear it so it would not brown.

                1. re: randyjl

                  I have definitely heard of that (practice of tearing lettuce). If this theory is true, then this means stainless steel knives do induce browning, which then means the plastic lettuce knife design has a point.

            2. Hey CK,

              Just use a cheap 6" Ceramic Chef's Knife...


              Potatoes and lettuce don't brown and they have other uses...d;^)