The Geometry of Cutting Bread...
Jan. 17th, 2025 02:16 pm...or, sexist subtitle, "Why Men* Never Cut Bread Properly", because that's what it seems to amount to in real life. ;) Ahem. So, a few nights ago, I met up with some other ladies for drinks. Somehow, this turned into one of us complaining bitterly about how her husband keeps producing Catastrophic!Bread!Spirals when cutting bread. Two others also agreed that, yes, their respective men also produce spirals rather than proper bread slices and how annoying that is. Well. I'm into technology and into knives, so, of course, I immediately took out pen and paper and produced some shitty construction drawings to show why the issue really comes down to hand size...
*I hope it's obvious this is not really a gender issue. Just that, statistically, any technical problem that exclusively hits people with very large hands is going to affect significantly more men than women.

In (1), you can see what cutting bread with an entirely straight bread knife should look like: In order to produce a clean cut, the knife is held completely horizontally, with all the teeth arriving down on the cutting board at the same time. At this point, if your hand is small enough and nothing else went catastrophically wrong, you should have produced a nice, regular slice of bread. (Because I was drunk while drawing, I'll provide translations. Tisch: table. Schneidbrett: cutting board. Brot: bread. Messer: knife. Kleine Hand: small hand. Also, no, this is not supposed to be an illustration of how to hold a bread knife... LOL)
But, oh noes, if the user's hand is too large, suddenly there's a problem! In (2), you can see that the fact that the fingers can't sink into the table surface causes the knife to be held at an angle! Under those circumstances, of course, there's an area of bread (marked orange) that's not going to be cut! And that's where the problem starts: the two main approaches to solve this are to either rip the underside of the bread (which results in really ugly slices for obvious reasons) or to rotate the bread. If you rotate the bread and your second cut does not perfectly align with the first (which it never does, not just because aligning two cuts perfectly always requires unusual levels of precision, but mainly because, hey, bread deforms when you suddenly exert pressure from a different direction, and while it's theoretically possible to correct for that, not everyone wants to fuck around with tensors during an otherwise uncomplicated kitchen task)? Catastrophic!Bread!Spirals are the logical result. Ladies, your men are neither malicious nor stupid, it's just that handing a completely straight bread knife without any kind of offset to a person with large hands is a shitty idea! (The same, of course, applies to any blade that's designed to arrive on the board surface completely horizontally. Like, also, absolutely anything with a sheepfoot blade...)
A possible solution is shown in (3): there are some bread knives with a bit of an offset that lowers the blade in relation to the handle, which means there's extra space for thicker fingers under the handle. (If you now immediately think "but this costs stability!, congratulations, you've been following my knife nerdery closely! Displacing the blade does cost stability. A knife like this will not withstand any hard impact. However, a bread knife is intended for cutting bread. If you are experiencing any kind of potentially blade-shattering impact on bread, there's most likely a bread malfunction... That is, unless you're the world's worst baker, or you intend to go into a knife fight with a bread knife - which I'd strongly advise against, even under the best of circumstances - this should never become an issue.) This extra space means that a person with large hands is now also able to hold the knife horizontally while cutting. YAY!
Other possible solutions to the problem, of course, include...
- using a thicker cutting board (which would also provide extra finger space, albeit in an impractical way... Generally, there's the recommendation your cutting board should be exactly as thick as your fingers* - not just for being able to place cuts in completely horizontal position at all, but also to provide a measure of when you've arrived on the board, with your fingers as the spacer, so you'll stop exerting pressure then, which protects your knives so you have to sharpen them less often - but at some point this becomes impractical as it results in very unwieldy cutting boards...)
- cutting at the edge of the table (which is going to be uncomfortable because you'll have to stand at an awkward angle or strain your shoulder, but, sure, this also provides extra finger space)
- cutting with reeeeaaally long arm motions (which is unergonomic as fuck, and you lose most of the advantage of that lovely serrated edge - as in, unless your knife is excellent, you're likely to shred the bread - so it only "works" in a very theoretical way but comes with other issues in practice)
*Yes, "a finger thick" as a measuring unit is not merely a historical relic; there are use cases when using your finger as a measuring unit actually fulfills an important practical purpose! Generally, when talking about tools, ergonomy, and so on, so much depends on an individual's hand that units like "a palm width" also have to be taken literally, and followed precisely, not as a guesstimate.
...but, really, it comes down to technology. I understand how painful it can be to watch Catastrophic!Bread!Spirals, but really, there's no need for a relationship conflict over this issue! (I simply got my boyfriend a bread knife he can actually use. It's now one of his favorite knives because, hey, if you like bread, the difference between being able to cut bread and not being able to cut bread really matters. Also, I guess it was a relief to learn that, nope, he's not that clumsy, he just had the wrong tool for the task.)
I'm also tagging this entry with Germany, because - obviously - this conversation scored very high on the VFGI (Very Fucking German Indeed) scale: People getting extremely emotional over bread - check. People getting extremely emotional over knives - check. Overly technical approach to, well, absolutely everything - check. Alcohol, alcohol, and more alcohol involved - check. The only reason this doesn't get a perfect score is that one of us arrived at the bar three minutes late.
*I hope it's obvious this is not really a gender issue. Just that, statistically, any technical problem that exclusively hits people with very large hands is going to affect significantly more men than women.

In (1), you can see what cutting bread with an entirely straight bread knife should look like: In order to produce a clean cut, the knife is held completely horizontally, with all the teeth arriving down on the cutting board at the same time. At this point, if your hand is small enough and nothing else went catastrophically wrong, you should have produced a nice, regular slice of bread. (Because I was drunk while drawing, I'll provide translations. Tisch: table. Schneidbrett: cutting board. Brot: bread. Messer: knife. Kleine Hand: small hand. Also, no, this is not supposed to be an illustration of how to hold a bread knife... LOL)
But, oh noes, if the user's hand is too large, suddenly there's a problem! In (2), you can see that the fact that the fingers can't sink into the table surface causes the knife to be held at an angle! Under those circumstances, of course, there's an area of bread (marked orange) that's not going to be cut! And that's where the problem starts: the two main approaches to solve this are to either rip the underside of the bread (which results in really ugly slices for obvious reasons) or to rotate the bread. If you rotate the bread and your second cut does not perfectly align with the first (which it never does, not just because aligning two cuts perfectly always requires unusual levels of precision, but mainly because, hey, bread deforms when you suddenly exert pressure from a different direction, and while it's theoretically possible to correct for that, not everyone wants to fuck around with tensors during an otherwise uncomplicated kitchen task)? Catastrophic!Bread!Spirals are the logical result. Ladies, your men are neither malicious nor stupid, it's just that handing a completely straight bread knife without any kind of offset to a person with large hands is a shitty idea! (The same, of course, applies to any blade that's designed to arrive on the board surface completely horizontally. Like, also, absolutely anything with a sheepfoot blade...)
A possible solution is shown in (3): there are some bread knives with a bit of an offset that lowers the blade in relation to the handle, which means there's extra space for thicker fingers under the handle. (If you now immediately think "but this costs stability!, congratulations, you've been following my knife nerdery closely! Displacing the blade does cost stability. A knife like this will not withstand any hard impact. However, a bread knife is intended for cutting bread. If you are experiencing any kind of potentially blade-shattering impact on bread, there's most likely a bread malfunction... That is, unless you're the world's worst baker, or you intend to go into a knife fight with a bread knife - which I'd strongly advise against, even under the best of circumstances - this should never become an issue.) This extra space means that a person with large hands is now also able to hold the knife horizontally while cutting. YAY!
Other possible solutions to the problem, of course, include...
- using a thicker cutting board (which would also provide extra finger space, albeit in an impractical way... Generally, there's the recommendation your cutting board should be exactly as thick as your fingers* - not just for being able to place cuts in completely horizontal position at all, but also to provide a measure of when you've arrived on the board, with your fingers as the spacer, so you'll stop exerting pressure then, which protects your knives so you have to sharpen them less often - but at some point this becomes impractical as it results in very unwieldy cutting boards...)
- cutting at the edge of the table (which is going to be uncomfortable because you'll have to stand at an awkward angle or strain your shoulder, but, sure, this also provides extra finger space)
- cutting with reeeeaaally long arm motions (which is unergonomic as fuck, and you lose most of the advantage of that lovely serrated edge - as in, unless your knife is excellent, you're likely to shred the bread - so it only "works" in a very theoretical way but comes with other issues in practice)
*Yes, "a finger thick" as a measuring unit is not merely a historical relic; there are use cases when using your finger as a measuring unit actually fulfills an important practical purpose! Generally, when talking about tools, ergonomy, and so on, so much depends on an individual's hand that units like "a palm width" also have to be taken literally, and followed precisely, not as a guesstimate.
...but, really, it comes down to technology. I understand how painful it can be to watch Catastrophic!Bread!Spirals, but really, there's no need for a relationship conflict over this issue! (I simply got my boyfriend a bread knife he can actually use. It's now one of his favorite knives because, hey, if you like bread, the difference between being able to cut bread and not being able to cut bread really matters. Also, I guess it was a relief to learn that, nope, he's not that clumsy, he just had the wrong tool for the task.)
I'm also tagging this entry with Germany, because - obviously - this conversation scored very high on the VFGI (Very Fucking German Indeed) scale: People getting extremely emotional over bread - check. People getting extremely emotional over knives - check. Overly technical approach to, well, absolutely everything - check. Alcohol, alcohol, and more alcohol involved - check. The only reason this doesn't get a perfect score is that one of us arrived at the bar three minutes late.
no subject
Date: 2025-01-17 04:10 pm (UTC)(Hi - Yoon sent me to you for art, but I love bread and precision too :) )
no subject
Date: 2025-01-17 05:26 pm (UTC)no subject
Date: 2025-01-17 07:31 pm (UTC)We are ignorant about knives (we have no interest in them and no general use for them) and your earlier discussion taught us that the restaurant was providing us the wrong type of knife: whatever it is, it's not a bread knife. It's not a flat thin blade, and it has no serrations.
But, we do have, in our kitchen, a block of kitchen knives that I looted from my dad's house when he passed away, and it has a bread knife. So, we took home a loaf of that bread from the restaurant and tested the bread knife on it, and it worked just fine - no piercing necessary. And, as you noted above, we could cut all the way through because he had his hand off the Schneidbrett so that his knuckles didn't stop the blade. Score one point for having the right tool for the right situation. (Also score one point for Duolingo, because I could read your notes on the drawings without the translations.)
Neither my husband nor I care if our bread is flat or spiral, but I expect that that is just personal taste. We just care that it tastes good. I bet my sister, who's very picky about culinary things, including presentation, would care.
no subject
Date: 2025-01-17 07:44 pm (UTC)"the restaurant was providing us the wrong type of knife: whatever it is, it's not a bread knife. It's not a flat thin blade, and it has no serrations"
Oh noes! That's... kind of unprofessional, and a restaurant really should know better. I mean, at least the people who work in the kitchen should know. (Heck, they probably do, but some manager type overruled them because a flat-edged knife matches the decor better, or whatever.)
"Neither my husband nor I care if our bread is flat or spiral, but I expect that that is just personal taste. We just care that it tastes good."
It depends. I guess if you ever tried to eat, say, honey on bread, you'd also begin to care about flat slices... ;) I don't care all that much about presentation either - but my boyfriend does, so we both usually attempt at least a vaguely acceptable presentation even when it's technically not required.
no subject
Date: 2025-01-17 07:46 pm (UTC)no subject
Date: 2025-01-17 07:50 pm (UTC)no subject
Date: 2025-01-17 10:39 pm (UTC)Will experiment tomorrow morning (I like bread too much to cut off an unwanted slice late at night).
no subject
Date: 2025-01-17 10:48 pm (UTC)no subject
Date: 2025-01-21 11:23 am (UTC)No, the sideways cut is just about getting a better bite (I eat real bread. With crusts. Yay British supermarkets for stepping up their game to match Aldi and Lidl and actually offering really tasty breads. I no longer have to bake my own in self-defense.)
What I actually do is have the bread on a cutting board and my hand in the empty space before it. I tried to get it to interfere, but that's such an awkward sideways position I can't do it.
Eating bread - FOR SCIENCE!
no subject
Date: 2025-01-21 02:15 pm (UTC)no subject
Date: 2025-01-17 11:20 pm (UTC)no subject
Date: 2025-01-17 11:24 pm (UTC)