question about a sharp knife that cant cut tomatoes well

[coxhaus]

The only reason for a garden is to grow a great tomato. Home grown tomatoes can't be bought.

I only eat a BLT in May and June when I can eat my home-grown tomatoes. Otherwise, the store-bought tomatoes are hard skin and no flavor.

Store bought tomatoes probably cut easier.

 

[ModRQC]

I'd have expected after three months that those tomatoes would have been cut by now. Probably too late now... all rotten. Overripe tomatoes now that's difficult to cut efficiently. Let's start a new thread!

 

[Bobby2shots]

Store-bought tomatoes are often not fully ripened, in order to reduce the possibility of damage during transport to market. They're artificially ripened (red skin) by exposing them to ethylene gas. The flesh of those unripened tomatoes is mostly tasteless,,,, like styrofoam. They might "look good" on the outside, but that's about it.

I grow my own tomatoes, and I never pick them until they're fully ripened. The taste is amaaaazing compared to most store-bought. How do I know if they're ripe on the vine? Well, I simply "cup" the palm of my hand under the tomato, and tap one side of the tomato with my finger-tips. If the tomato "falls" into my hand,,,, it's ripe. When I cut them open, the flesh is completely red. Deeeeelicious.

FWIW, I'm in south-western Quebec. The weather here has started turning cold. Night-time temperatures last week (end of September) were well into single digits (4* Celsius/39* Fahrenheit), and I've still got tomatoes growing in my garden. The "season" is mostly done, and I'll be picking the remainder as soon as the first hard frost is forecasted.

That said, I have absolutely zero problems getting see-through tomato slices with my 6.25" Victorinox petty/utility/sandwich knife, which is approaching three years old, and has never once been sharpened on stones. Honing only, "feathering" with a ceramic rod. Cuts on the first stroke, regardless of how acute the cutting angle is.

This years' harvest was quite amazing. With 18 plants, I've managed to get hundreds of tomatoes. I give away most of them to friends and family, and we've frozen more than enough to get through winter. Our growing season here starts the last weekend of May, and lasts into the beginning of, or middle of October.

 

[ModRQC]

Yep pretty much the same over here, still harvesting from my plants every night. Soon will have to pick everything. It's getting colder fast these days.

 

[gregfisk]

Yep pretty much the same over here, still harvesting from my plants every night. Soon will have to pick everything. It's getting colder fast these days.

I just cut down my last tomato plant this last weekend. Really sorry to see them go. I agree with everything that you said in your earlier posts. Nothing beats a fresh tomato!

 

[ModRQC]

I just cut down my last tomato plant this last weekend. Really sorry to see them go. I agree with everything that you said in your earlier posts. Nothing beats a fresh tomato!

It was not me. @Bobby2shots made the louange of fresh tomatoes back there.

 

[gregfisk]

It was not me. @Bobby2shots made the louange of fresh tomatoes back there.

sorry, grabbed the wrong post.

 

[r0bz]

i resharpened the knife with only a 800 gritstone the knife now cuts tomatoes insanly good .....
but carrots are hard to cut what may be the problem ?

 

[stringer]

i resharpened the knife with only a 800 gritstone the knife now cuts tomatoes insanly good .....
but carrots are hard to cut what may be the problem ?

Try more lateral slicing motion in your cut. Don't just push straight down.

 

[r0bz]

Try more lateral slicing motion in your cut. Don't just push straight down.

what i mean is that it is hard to cut the carrots i need to put some force into it compared to cutting cabbage or cucumber or potatoes things like that i cut it with ease and no need to apply force

 

[stringer]

what i mean is that it is hard to cut the carrots i need to put some force into it compared to cutting cabbage or cucumber or things like that where i put almost no pressure

Try more lateral slicing motion in your cut. Don't just push straight down. Especially for dense veggies. It helps a lot even if you're knife is thick and wedgie.

 

[r0bz]

Try more lateral slicing motion in your cut. Don't just push straight down. Especially for dense veggies. It helps a lot even if you're knife is thick and wedgie.

i always find it hard cutting dense vegetable if you have more tips i will be glad to hear

 

[HumbleHomeCook]

Try more lateral slicing motion in your cut. Don't just push straight down. Especially for dense veggies. It helps a lot even if you're knife is thick and wedgie.

This. ^

Try a more forward slicing motion as you push down and it will likely help. However, the primary grind of the knife will only allow for so much on dense veggies like carrots. I have knife that starts into a carrot like a razor but about halfway through starts to pop it apart as much as slice it and that's because the knife widens out rather quickly.

 

[Jovidah]

There's a significant chance that the problem isn't your edge, but the thickness behind the edge. Cutting hard stuff like carrots is more about thickness behind the edge than the actual edge itself. No matter how good of a razor's edge you have, if the knife is too thick behind it it'll wedge and eventually split the product, instead of cutting through smoothly. Even a mediocre edge will do decent as long as it's thin enough behind the edge.
The only real solution to this is thinning behind the edge.

 

[JDC]

Aside from all the good responses so far,,,, I'd be willing to bet that your main issue has to do with using too much pressure on your finish strokes, effectively causing the blade's apex to tilt more to one side than the other. You can quickly check if that's the case by verrrrryyyy lightly dragging the pad of your thumb across the blade edge,,,, left to right,,,, then, right to left. If the blade seems to bite a bit more in one direction compared to the other, then that's a sure sign. If that's the case, try stropping the blade VERY LIGHTLY on your finish stone, no more than 1 pull per side at a time. A few strokes should fix the issue, or at the very least, provide an improvement.

Also, check the entire blade length for tilt,,, because.... depending how you stroked the stone, you may find that one portion of the blade tilts to one side for half the length of the blade, and tilts opposite along the remainder of the blade's length.

And,,,,,,,, get yourself a 2k, or 3k or 4k stone. 800 to 8k is too big a jump.

Simple answer is that it isn’t as sharp as you think it is.
Super polish done well will fall through tomato skins. Look at a couple of Salty’s videos (the OG of the tomato slice vid)





Just leave it at 800grit if it’s working well off that stone.

As my sharpening experience grows, I tend to agree with these.
"The stone is too fine such that the knife won't cut through skinned vegetables" might be one of the biggest misunderstandings on the forum.

 

[coxhaus]

As my sharpening experience grows, I tend to agree with these.
"The stone is too fine such that the knife won't cut through skinned vegetables" might be one of the biggest misunderstandings on the forum.

I would think the type of steel would also play a part in how well the steel can cut tomatoes. The composition of the steel.

 

[cotedupy]

Here's a follow-up post to my one earlier on this thread: Knife Sharpening Thread

Very long story short... you *can* have a very sharp edge that is too refined to cut a tomato at an acute angle. It's kinda how a straight razor works - it has a kind of sharpness that has come from being highly refined, but not at a stupidly acute angle. So it doesn't cut into your (or the tomato's) skin.

Even shorter - it's all about friction.

 

[Delat]

Just to add a data point - I can take a knife (AS and White 2) up to HHT3 on an SG4k at 15dps and it cuts tomatoes just fine - either with a slice or chop cut. I’m not doing super-thin slices with a thick edge that would run into the geometry issues @cotedupy calls out, though.

For the question on carrots, effort is definitely directly related to how thin the knife is behind the edge all the way up to full portion of the blade that will be buried in the carrot. You can see it on many of the carrot-cutting comparison vids over on the cutting thread where posters presumably have all their knives sharpened exactly the same way but some clearly cut more effortlessly than others.

Anytime I have trouble with a cut in anything, I add more slicing motion as pointed out by @stringer .

Here’s my own carrot video. It’s subtle, but you can see the Yoshikane (the k-tip) moves through the carrots more easily than the other two. When I switch to using the back 1/3 of the edge, you can see and hear the Myojin (the shorty 180mm) takes a bit more effort due to the thicker grind in that area. Some knives are ground so the back half is thicker and more work-horse while the front half is more laserish. On all my cuts you can see I’m using a slicing motion and not a straight chop or guillotine & glide.

 

[r0bz]

There's a significant chance that the problem isn't your edge, but the thickness behind the edge. Cutting hard stuff like carrots is more about thickness behind the edge than the actual edge itself. No matter how good of a razor's edge you have, if the knife is too thick behind it it'll wedge and eventually split the product, instead of cutting through smoothly. Even a mediocre edge will do decent as long as it's thin enough behind the edge.
The only real solution to this is thinning behind the edge.

i think when i will have the time i will thin the knife if you have tips on how it should be performed i will be glad to hear as i have never done it before

 

[Bobby2shots]

i think when i will have the time i will thin the knife if you have tips on how it should be performed i will be glad to hear as i have never done it before

If it's your first time, you might want to try something like this;

Practice your stroke "before" actually sharpening or thinning, and do it on a non-abrasive flat surface. Basically, you start by putting the flat face of your blade against the flat surface. Do this in good light. You'll see a tiny shadow appear between the apex of the blade, and the flat surface. Rotate the knife's handle slightly so that the apex of your blade now touches your flat surface, and the "shadow" disappears. You now know the extremes of how much tilt you apply to the blade. Now, find the sweet spot between those two angles, lock your wrist in that position, and do nice long strokes along the length of the surface. Don't rush it,,, just aim for consistency at this point.

Once you're comfortable with your stroke's consistency, try it on a stone. Make sure that your stone is at an appropriate height. Your elbows should be raised as you push/pull back and forth. You don't want the stone to be too low, or you'll be swinging your arm, and pivoting from the shoulder, and that will vary your angle.

Let the stone do the work,,,, don't force excessive pressure on the blade. Once you've done a few strokes on one side, switch hands and repeat on the other side of the blade. That should be it,,,,, Don't try to overdo it. Don't keep going back and forth from one side to the other. Do a test cut to see if there's an improvement, and if not,,, repeat the same process. If you need an excessive number of strokes, you're probably using the wrong stone. If your angle is too shallow, and you're worried about scratching the side of the blade, try wrapping a strip or two of masking tape along the length of the spine.

 

[r0bz]

If it's your first time, you might want to try something like this;

Practice your stroke "before" actually sharpening or thinning, and do it on a non-abrasive flat surface. Basically, you start by putting the flat face of your blade against the flat surface. Do this in good light. You'll see a tiny shadow appear between the apex of the blade, and the flat surface. Rotate the knife's handle slightly so that the apex of your blade now touches your flat surface, and the "shadow" disappears. You now know the extremes of how much tilt you apply to the blade. Now, find the sweet spot between those two angles, lock your wrist in that position, and do nice long strokes along the length of the surface. Don't rush it,,, just aim for consistency at this point.

Once you're comfortable with your stroke's consistency, try it on a stone. Make sure that your stone is at an appropriate height. Your elbows should be raised as you push/pull back and forth. You don't want the stone to be too low, or you'll be swinging your arm, and pivoting from the shoulder, and that will vary your angle.

Let the stone do the work,,,, don't force excessive pressure on the blade. Once you've done a few strokes on one side, switch hands and repeat on the other side of the blade. That should be it,,,,, Don't try to overdo it. Don't keep going back and forth from one side to the other. Do a test cut to see if there's an improvement, and if not,,, repeat the same process. If you need an excessive number of strokes, you're probably using the wrong stone. If your angle is too shallow, and you're worried about scratching the side of the blade, try wrapping a strip or two of masking tape along the length of the spine.

should i do it on a 400 gritstone or 800 ?
if you know a good vid on the topic please send

 

[matchplay18]

Just my two cents. Because there is a lot of good advice here. But after awhile the lines are blurred. You need to find a good source of information. And I will say it this way, right of wrong you will develop your own interpretation of the fundamentals. I have been sharpening peoples knives for over thirty years. Advice on this subject nothing short of infinite. Even before you consider what type of sharpening stone to use. I would like to suggest you familiarize yourself with these terms. Micro abrasion, Burnishing, Apex, Convex, Keen edge, String, Degree of angle. Hopefully it will put things more into perspective when first learning to sharpen a knife. A good reference and the theory applies The Pasted Strop. I here people talking about using 5k to 6k to 8k and higher grit stones, but don't get ahead of yourself 99.5% of the sharpening is done on the 600 to 800 to 1000 lower grit stones. Somehow you need to practice practice practice. Just my two cents

 

[r0bz]

Just my two cents. Because there is a lot of good advice here. But after awhile the lines are blurred. You need to find a good source of information. And I will say it this way, right of wrong you will develop your own interpretation of the fundamentals. I have been sharpening peoples knives for over thirty years. Advice on this subject nothing short of infinite. Even before you consider what type of sharpening stone to use. I would like to suggest you familiarize yourself with these terms. Micro abrasion, Burnishing, Apex, Convex, Keen edge, String, Degree of angle. Hopefully it will put things more into perspective when first learning to sharpen a knife. A good reference and the theory applies The Pasted Strop. I here people talking about using 5k to 6k to 8k and higher grit stones, but don't get ahead of yourself 99.5% of the sharpening is done on the 600 to 800 to 1000 lower grit stones. Somehow you need to practice practice practice. Just my two cents

i want to thinn a knife ...
i was asking about that at what grit to start i have a 400 gritstone and a 800

 

[Bobby2shots]

should i do it on a 400 gritstone or 800 ?
if you know a good vid on the topic please send

If that's what you've got, use your 400..... buy it's a little more "involved" than that. You should very rarely need to thin if you're a typical home-cook, and, when you do thin, you only need a tiny bit at a time. It depends on many factors, such as how many times has this knife been re-sharpened in its' lifetime, and just how much the apex has receded over time. The type of knife is another factor;,,, you're simply not going to turn a thicker all-rounder western chef knife into a nakiri or an usuba, nor should you want to. Expectations must be realistic. Balance and compromise are the key with all-rounders, otherwise you sacrifice durability for sharpness when you actually want degrees of both characteristics.

The choice of stone-type should depend on the hardness of the blade you're trying to thin, and the grit of that stone will generally determine how long it takes you, etc. (diamonds, vs Silicon Carbide, vs ceramic, vs aluminum oxide, as well as binding process)

I'll try to find you a decent video.

 

[M1k3]

Just to add another variable into the mix, flat bevels increase friction, reducing ease of cutting.

 

[Jovidah]

Thinning is basically just sharpening at a really low angle. Think of it taking the shoulders off the bevels. The two main issues:
-It will really **** up your blade finish, especially if you're still new to it, since you're likely to wobble a bit. Your knife absolutely will look like it's been dragged behind a truck for a few kilometers through gravel.
-Good chance you'll blunt the edge too in the process, so I always do thinning first, and doing the edge after.

Doing it by hand is a slow process so always start at your lowest grit stone. The idea is lower grit --> bigger sharpening grit --> bigger grooves in the metal while thinning --> faster progress.

 

[Bobby2shots]

Here ya go;

 

[stringer]

When a knife is properly thinned it shouldn't have trouble even in very hard dense veggies like sweet potatoes. But you need good technique too. Which involves thrusting forward as you push down. Any steel edge is much more effective at slicing with lateral movement than it is at cutting straight up and down.

 

[MowgFace]

This thread makes me think of Salty.

 

[Benuser]

You may find out under which angle the knife cuts the best by letting it take itself its position through hard stuff. Take a Granny Smith. Apply the lightest possible pressure, less than the blade's weight, with a very loose grip, and pulll gently if you normally would slice forward. It's quite common with asymmetric blades to see it taking a position of some 20 degrees. That is how it encounters the least friction. By sharpening you may change this behaviour a bit, especially by thinning the right side behind the edge, lowering its sharpening angle the on the right side, make the right bevel flush with the face and increasing the angle on the left side, all to somewhat balance the friction on both sides. Please be aware that with an asymmetric blade the edge is off-centered to the left. That explains the steering we want to compensate for.