This guy just really, really wants to use his slide rule. A cheap gram-accurate scale and an electronic calculator are a more...scalable kitchen solution.
Also, not all ingredients in a recipe scale linearly--most notably spices, tinctures, and any fermentation components.
The point of the article is that he can set the C and D scales to the proportion he needs, one time, and then just move the slider around for each ingredient, rather than doing a different calculation for each ingredient. Knowing when to vary the proportion is just basic cooking knowledge which would have to be applied either way.
>The point of the article is that he can set the C and D scales to the proportion he needs, one time, and then just move the slider around for each ingredient, rather than doing a different calculation for each ingredient.
Is punching a number into a calculator and then multiplying by M (memory function, for the scale factor) really that much work than carefully sliding tithe slider into position and reading/eyeballing the output?
This is indeed the point. Even with messy hands you can just look at the slide rule and read off the right amounts. No need to touch the calculating device.
It's not at all more work... I agree with the OP, this is a guy who really wants to use his slide rule and is pushing it over other (better) solutions.
Compared to the suggestion of a calculator + scale (or a voice assistant, IMO), I think the annoying part is when you hit weird fractions, especially in the US.
Random dumb example: say you need 6/7ths of 3/4 of a tablespoon of table salt... or 0.64 tablespoons. That's not gonna be a common measuring device.
Look it up in terms of grams, though, call it 20g per tablespoon (or measure the original amount in grams if you like), multiple by .64, get 12.8g, use your scale to get ~13. I'm more confident in my ability to get 13g with my scale than I am to get 0.64 tablespoons (half + half of a quarter is what I'd have to use with my measuring stuff, and the "half of a quarter" is annoying when they're rounded and all...). If your voice assistant can take care of the conversions, it GREATLY speeds it up too.
(The observant could respond here that 0.64 tablespoons is damn close to 2 teaspoons and so this example off the top of my head is dumb. Which is true, but frankly I have to look up a bunch of those sorts of things any time I try them, and it could've landed on something more awkward like 0.4 tablespoons total.)
> The observant could respond here that 0.64 tablespoons is damn close to 2 teaspoons ...
Correct, first thing I thought of. :-)
> ... and it could've landed on something more awkward like 0.4 tablespoons total.
Let me try to tackle that one. 1 tablespoon = 3 teaspoons, so that's 1.2 teaspoons. Most tablespoon & teaspoon sets have a 1/4 teaspoon as the smallest available measurement, so I'd probably make that 1.25 teaspoons and leave the 1/4 teaspoon not quite full.
I know several families who homeschool. Getting kids to help you in the kitchen is apparently a very good way to get them comfortable with doing math with fractions.
Incidentally, our own problems go the other way. My wife likes to get recipes from American recipe sites that give measurements in cups or tablespoons, but we live outside America (I got a job overseas) so the local store sells things in grams or kg. So when I'm doing the grocery shopping on my way home from work, I often have to look up "how much does one cup of sour cream weigh" to know whether I should buy the 250g package or the 1kg package. Once the ingredients arrive in the kitchen, we find the fraction math easy. (Though we also, very often, make use of the kitchen scale in measuring ingredients).
Interesting. Could you give an example? The only example I could think of is when one is making a big ball of something and needs to cover the surface with another ingredient or preparation then it would scale as ^2/3.
In general seasoning (or saucing) anything solid is more about exposed surface area than mass, and this depends on things like cut sizes, evaporation shrinking, and god knows what other factors. It doesn't scale with simple math, because there are all sorts of other factors involved that complicate this (surface texture just being one).
It is also all moot because ingredients (especially spices) have massive variance in potency, sweetness, bitterness, sourness, etc., so recipes are only ever a guideline. I.e. if you double a spice that is twice / half as potent as expected, you can get an unpalatable / bland dish, and IMO factors between 0.25 to 4.00 are extremely common for plenty of ingredients. So you always just need to taste and adjust accordingly. This is also ignoring that certain ingredients can vary in multiple dimensions (e.g. a lemon that is a lot sweeter than expected but less sour, and so simple scaling of the lemon alone can't get you want want: you need to reach for white sugar and/or citric acid to get your desired pH and sweetness).
It is also a fantasy that all flavour concentrations are perceived linearly anyway (and this is especially the case for acidity / sour / pH generally, but also spiciness in e.g. ginger, pepper, capsaicin).
Last year I picked up a bamboo Hemi and worked through the (70yo!) workbook. The trigonometric scales are cool. Making a single slide to find all the sides of a triangle is surprisingly satisfying. It got me to realize that, sliderules with the right scales can solve the roots of any 3-variable equation. I guess this is why there was a proliferation of industry-specific sliderules back in the day.
More generally, aren't simple, well-engineered analog tools so satisfying?
That's so cool. Like mathematical primitive archeology. The history of these sorts of analog computing devices that physically encode non-linear mathematical relations is fascinating.
With much tutoring, I learned to use a sextant and doing that gives one some sense of the "sorcery" and power achievable with blue-water navigation.
Boyer and Merzbach cover some of the development of these tools in their "History of Mathematics". Highly recommended.
People should just be into slide-rules period. Particularly in the West. We are always so amazed when people in Asia beat people with calculators using their abacuses, but the West had its mechanical computing device too, and like the abacus it can beat a calculator if used well.
I don't see how a slide rule would substantially improve anything in my kitchen, honestly.
> Bakers understand the importance of proportions in cooking; they even write their recipes normalised to the weight of flour, meaning all other ingredients are given in proportion to the amount of flour.
I do more baking than cooking. Baker's math is an incredibly useful concept. But that math is trivial to do in my head, and that's much more convenient than a slide rule or other calculating device.
Very cool, I've never used a slide ruler but I can see how in logarithmic space, that 3.3/2 scaling factor simply becomes a distance you add.
Makes me want to get one now, because I like the concept of memorizing ratios rather than recipes (thanks to the popular eponymous book), and this seems more convenient (and satisfying) for non-trivial computations than getting my screen dirty or dictating it to an assistant.
I think such scaling as the author suggests, can be done in the head. 57g is roughy 3/4 of 80g. It's trivial to take 3/4 of almost anything. 250g -> ~180..185g, 40 -> 30, 50 -> 37g. Unless you do bakery, where proportions are very important, there's no need for 3 digit precision.
And yes, in general a slide ruler is a great tool. I should try it again.
i'm just not a serious enough cook, my kitchen's temperature varies humidity too the water coming out of the tap is random too so I just gave up at the end. Nowadays I read couple of recipes to get the gist of it, define the theme in my head and just go to town... I almost never have all the ingredients, so I substitute at will. I guess one instrument that I still use regularly is my Thermapen, food safety calls for one; and family feels more reassured when they see chicken breast that is ever so slightly pink but the temp reading suggests it's safe lol
Weight is a lot harder to use than volume. If I'm measuring a cup of flour (for example), I dip my measuring cup in, level it off, and I'm done. Takes a few seconds. If I use a scale, I have to watch the scale carefully until I'm getting close, then slow down my rate of pouring into the bowl greatly so that I don't go over. Sometimes I will still go over despite my best efforts, and then I have to take flour out to get the measurement right*. It's a huge faff, and it doesn't even produce a better result the vast majority of the time. Some recipes are finicky and do better with a scale, but 90% of the time volume measurements are much faster for the same result.
* and to head off the obvious "just don't worry about it if you go a few grams over" rebuttal: that defeats the purpose of using a scale for precision! So either you don't worry about the wiggle room in measurements (at which point just use volume, it's faster), or you strive for precision and it takes you much more work. Either way it's a worse solution unless you really, truly need maximum accuracy.
The imprecision of volumetric measurements can absolutely ruin much baking, and many other recipes based on things like surface areas, or where the perception of flavours does not scale linearly with things like either volume or mass of the ingredient.
You're right volumes seem easier, at first blush, but the cost of this easiness is a dramatic / considerable reduction in consistency, compared to when measuring by mass.
Once you switch to regularly scaling by mass (just as a guideline, and still adjusting to taste, texture, and other factors), you'll realize the apparent easiness of volumes is pure illusion, and actually makes getting good results much harder.
Yes but the packing density of flour varies cup to cup, within the same measuring cup, resulting in different amounts of flour.
> J. Kenji Lopez-Alt, the managing editor of the blog Serious Eats, once asked 10 people to measure a cup of all-purpose flour into a bowl. When the cooks were done, Mr. Lopez-Alt weighed each bowl. “Depending on how strong you are or your scooping method, I found that a 'cup of flour’ could be anywhere from 4 to 6 ounces,” he said. That’s a significant difference: one cook might be making a cake with one-and-a-half times as much flour as another.
So you have to carefully scoop precisely the same way every time to even be close to accurate??
Baking--along with fermentation, curing, and certain brines or other solutions--is the subset of cooking where accuracy of the masses of ingredients matters more than most others.
And yet still you are right you must often adjust significantly in baking for other factors (temperature + yeast activity, humidity, flour grind and composition, and general feel on kneading).
One of the major problems with this theory is that "cup" doesn't have any standard definition - and measuring scoops marked as "1 cup" - can be anywhere (ignoring outliers) from 240, 236.6 or 227 ml. So - ignoring the fact that when you scoop flour - the same scooped "cup" can vary by as much as 10-15%, the cup itself may be off by 6%. And you are never quite sure which cup the original recipe maker was using.
This is why any half-ways sane baker works off a scale.
And? Recipes might end up needing 1/3 more total flour just depending on the season, why should I care about how accurate it is to some kitchen separated by geography, time, and ingredients? If it doesn't taste right/feel right/look right, you'll know, and then you fix it.
I think the argument is that commercial recipes in the US are written in proportional notation, e.g. 1:2:3 sourdough, but recipes in countries which use metric give units, e.g. 1kg:2L:3kg. I also note that if you add small proportions of an ingredient, e.g. salt, it might be easier to change units in metric (5g salt) while it would be easier to write proportionally in imperial (0.005 parts salt) if you were then going to scale to to a tonne/ton of dough.
I have no idea if this is true but it sounds like a coherent argument that isn't just volumetric vs mass units.
This is great! I actually just bought a slide rule a few weeks ago (a Pickett N902-ES), and I've been working through the original booklet. One reason I bought it was to get a different perspective on calculation, since I never used a slide rule in school. Case in point: I do a lot of cooking, and this use case never occurred to me.
If your goal is a different perspective on calculation, I warmly recommend learning mental maths with logarithms too. Not only does it complement slide rule practise, but it also gives you a linear/additive understanding of multiplication/powers which is useful.
I don't understand complex numbers and time--frequency domain translations but I suspect a log understanding feels similar to those.
Only in Imperial/United States customary units. They start with a few unconvincing metric examples, then throw away the pretence and jump right into cups, tbsp, etc.
If you'd stop using Imperial, and started using metric + scales, the entire problem domain no longer exists.
Scales are fine, but you're going to need scoops anyway. However, once you've made a recipe before, you probably won't need the scale to make it a second time. Volume measuring equipment is useful for more than measurement, can be easily multiplied or halved, never needs calibration, charging or changing of batteries, and you're going to be estimating anyway once you've gotten familiar with a recipe. It's also very easy to estimate without any standard measuring equipment at all.
> you're going to be estimating anyway once you've gotten familiar with a recipe
I would disagree slightly for this when it comes to making precise doughs or other things like brines, syrups, candy, and etc. Or at least I would change "estimating" to "adjusting" in your statement above. When it comes to trying something new (whether in baking from a proper source, like e.g. Modernist Bread or Modernist Pizza, or otherwise), a scale is invaluable.
But yeah, once you have some something a few times and have the feel, you can convert to volumes and go based on your senses. There's a baseline science / formula to some cooking, but the rest really is art.
This feels like a nit, because really I am just glad to see someone else pointing out the obvious realities here. While I would be hesitant to try Mr. Slide Rule's cooking, I'd try your cooking without fear!
Bases for cases. One of the advantages of Imperial measurements is that they are divisible by more factors than 2 and 5. This is where metric falls down for cooking. NB: I know the metric system and use it daily, but it's not perfect for every use case.
I have created a python program for exactly that purpose. Its nothing fancy. A yaml file of ingredients, another yamk fole of recipes and a yaml file for nutrient target and then some optimizers and some constaimt enforcers. I can now decide what I want to eat that day and the program tells me what quantity I should eat, what ingredients I need, what ingredient I need to buy, how much time it will take for cooking and how much meal prep boxes etc
Extremely helpful for weight loss
What I would actually like in every kitchen is a scale and a lookup table for the weight of a cup of flour, cup of rice, mL of oil, etc. No more volume based measurements.
This is impossible for most ingredients because many ingredients (flour, oil, or almost all such ingredients) vary considerably depending on packing, composition, and a whole host of other factors, and, also, not all recipes need to be scaled by mass.
If you see a recipe involving flour and it uses volume, it is trash, will not be reproducible. All serious baking is done by mass and mass only, except for glazes / coatings and/or if a very specific product / brand is specified. EDIT: as another commenter here noted, yeast also does not scale linearly (obviously) except in special cases.
Also, oils in general should be measured neither by volume nor by mass, but relative to what they need to coat / submerge (be that an ingredient, a cooking surface, or some combination of the two), or, for deep-frying, based on the amount needed to not drop temperature too significantly for whatever batch you are frying. That is, much cooking is about surface areas of your ingredients.
As another commenter noted, few things in cooking actually scale linearly, and, in general, if you are following recipes mechanically like this, you produce sub-par results. You always have to adjust quantities for ingredient freshness, humidity, ingredient variance, and other variables, so recipes are only ever guidelines at best. And seasoning is always to taste (your own, and whomever you are cooking for) anyway.
But, sure, I guess this helps you scale up those guidelines in some rare cases where that math isn't trivial to do in your head...
Professional chefs recipes are all in proportions to begin with. For example for a baker everything else in a recipe is in proportion to the weight of the flour.
As a hobbyist cook, this article starts with a false (or at least misleading) premise:
maybe the recipe calls for 80 g of butter but you only have 57 g
The amount of fat is rarely critical, pie crusts and puff pastry the exceptions. Unless the situation is puff pastry, make the full recipe. There are also recipes, like Better Homes and Gardens cookbook "baked rice pudding", that you can fudge ingredients to an extent, but can't double. The heat transfer of a double sized batch of custard prevents the whole thing from cooking.
The point being that food is more and less than chemistry. It's more and less than thermodynamics or heat transfer. It's art.
PS
I own 2 slide rules. I don't use either one in the kitchen.
Truth. To be blunt, while some aspects of some recipes can be scaled linearly, others can not.
Bakers percentages (measuring by-weight as a percentage of the largest mass ingredient (usually flour or water)) only work for lean dough and only for the non-fermenting components of that dough.
Put more concretely, one does not linearly scale the yeast in a lean dough. It results in far too rapid a fermentation, over-proofed dough, and less flavor complexity.
This. Belief in linear scaling of recipes is such a quick tell for someone who hasn't done even the most basic home cooking (or someone who has no sense of taste / texture at all).
I think I own three. My grandfathers, my father's, and a cheap one I picked up at a garage sale as a kid.
I'd never put them near my kitchen - too precious. Also, not necessary? Today I readjusted the measurements for a chemistry experiment by 50% without a calculation aid and it's really not that hard.
> I just found myself in someone else’s kitchen and they didn’t have a slide rule.
What? No way that happened! In all seriousness though I almost never find myself in the need to multiply anything in the recipe by the amount different than some multiple of 0.5 and these are pretty easy to do in my head.
i believe i threw a slide ruler in the trash recently. i stopped reading as soon as they said something about a c position. i’d rather have a digital scale- so many fewer measuring cups/spoons used, just do the addition in your head or tare as you add additional ingredients.
Also, not all ingredients in a recipe scale linearly--most notably spices, tinctures, and any fermentation components.
Is punching a number into a calculator and then multiplying by M (memory function, for the scale factor) really that much work than carefully sliding tithe slider into position and reading/eyeballing the output?
Random dumb example: say you need 6/7ths of 3/4 of a tablespoon of table salt... or 0.64 tablespoons. That's not gonna be a common measuring device.
Look it up in terms of grams, though, call it 20g per tablespoon (or measure the original amount in grams if you like), multiple by .64, get 12.8g, use your scale to get ~13. I'm more confident in my ability to get 13g with my scale than I am to get 0.64 tablespoons (half + half of a quarter is what I'd have to use with my measuring stuff, and the "half of a quarter" is annoying when they're rounded and all...). If your voice assistant can take care of the conversions, it GREATLY speeds it up too.
(The observant could respond here that 0.64 tablespoons is damn close to 2 teaspoons and so this example off the top of my head is dumb. Which is true, but frankly I have to look up a bunch of those sorts of things any time I try them, and it could've landed on something more awkward like 0.4 tablespoons total.)
Correct, first thing I thought of. :-)
> ... and it could've landed on something more awkward like 0.4 tablespoons total.
Let me try to tackle that one. 1 tablespoon = 3 teaspoons, so that's 1.2 teaspoons. Most tablespoon & teaspoon sets have a 1/4 teaspoon as the smallest available measurement, so I'd probably make that 1.25 teaspoons and leave the 1/4 teaspoon not quite full.
I know several families who homeschool. Getting kids to help you in the kitchen is apparently a very good way to get them comfortable with doing math with fractions.
Incidentally, our own problems go the other way. My wife likes to get recipes from American recipe sites that give measurements in cups or tablespoons, but we live outside America (I got a job overseas) so the local store sells things in grams or kg. So when I'm doing the grocery shopping on my way home from work, I often have to look up "how much does one cup of sour cream weigh" to know whether I should buy the 250g package or the 1kg package. Once the ingredients arrive in the kitchen, we find the fraction math easy. (Though we also, very often, make use of the kitchen scale in measuring ingredients).
It is also all moot because ingredients (especially spices) have massive variance in potency, sweetness, bitterness, sourness, etc., so recipes are only ever a guideline. I.e. if you double a spice that is twice / half as potent as expected, you can get an unpalatable / bland dish, and IMO factors between 0.25 to 4.00 are extremely common for plenty of ingredients. So you always just need to taste and adjust accordingly. This is also ignoring that certain ingredients can vary in multiple dimensions (e.g. a lemon that is a lot sweeter than expected but less sour, and so simple scaling of the lemon alone can't get you want want: you need to reach for white sugar and/or citric acid to get your desired pH and sweetness).
It is also a fantasy that all flavour concentrations are perceived linearly anyway (and this is especially the case for acidity / sour / pH generally, but also spiciness in e.g. ginger, pepper, capsaicin).
https://sliderulemuseum.com/
Last year I picked up a bamboo Hemi and worked through the (70yo!) workbook. The trigonometric scales are cool. Making a single slide to find all the sides of a triangle is surprisingly satisfying. It got me to realize that, sliderules with the right scales can solve the roots of any 3-variable equation. I guess this is why there was a proliferation of industry-specific sliderules back in the day.
More generally, aren't simple, well-engineered analog tools so satisfying?
With much tutoring, I learned to use a sextant and doing that gives one some sense of the "sorcery" and power achievable with blue-water navigation.
Boyer and Merzbach cover some of the development of these tools in their "History of Mathematics". Highly recommended.
> Bakers understand the importance of proportions in cooking; they even write their recipes normalised to the weight of flour, meaning all other ingredients are given in proportion to the amount of flour.
I do more baking than cooking. Baker's math is an incredibly useful concept. But that math is trivial to do in my head, and that's much more convenient than a slide rule or other calculating device.
Makes me want to get one now, because I like the concept of memorizing ratios rather than recipes (thanks to the popular eponymous book), and this seems more convenient (and satisfying) for non-trivial computations than getting my screen dirty or dictating it to an assistant.
And yes, in general a slide ruler is a great tool. I should try it again.
In metric countries, a small kitchen scale is very common. The US seems to run on volume, rather than weight.
* and to head off the obvious "just don't worry about it if you go a few grams over" rebuttal: that defeats the purpose of using a scale for precision! So either you don't worry about the wiggle room in measurements (at which point just use volume, it's faster), or you strive for precision and it takes you much more work. Either way it's a worse solution unless you really, truly need maximum accuracy.
You're right volumes seem easier, at first blush, but the cost of this easiness is a dramatic / considerable reduction in consistency, compared to when measuring by mass.
Once you switch to regularly scaling by mass (just as a guideline, and still adjusting to taste, texture, and other factors), you'll realize the apparent easiness of volumes is pure illusion, and actually makes getting good results much harder.
Baking is based on proportions. As long as you use the same measuring tool, the details don’t matter.
2 cups of flour works regardless of the size of your cup
> J. Kenji Lopez-Alt, the managing editor of the blog Serious Eats, once asked 10 people to measure a cup of all-purpose flour into a bowl. When the cooks were done, Mr. Lopez-Alt weighed each bowl. “Depending on how strong you are or your scooping method, I found that a 'cup of flour’ could be anywhere from 4 to 6 ounces,” he said. That’s a significant difference: one cook might be making a cake with one-and-a-half times as much flour as another.
So you have to carefully scoop precisely the same way every time to even be close to accurate??
And yet still you are right you must often adjust significantly in baking for other factors (temperature + yeast activity, humidity, flour grind and composition, and general feel on kneading).
This couldn't be more wrong and no serious baking is done by volume for dry ingredients (flour, yeast, sugar, salt preferments, other additives).
This is why any half-ways sane baker works off a scale.
Anyway, it's not really an issue.
I have no idea if this is true but it sounds like a coherent argument that isn't just volumetric vs mass units.
I don't understand complex numbers and time--frequency domain translations but I suspect a log understanding feels similar to those.
https://entropicthoughts.com/learning-some-logarithms
Only in Imperial/United States customary units. They start with a few unconvincing metric examples, then throw away the pretence and jump right into cups, tbsp, etc.
If you'd stop using Imperial, and started using metric + scales, the entire problem domain no longer exists.
I would disagree slightly for this when it comes to making precise doughs or other things like brines, syrups, candy, and etc. Or at least I would change "estimating" to "adjusting" in your statement above. When it comes to trying something new (whether in baking from a proper source, like e.g. Modernist Bread or Modernist Pizza, or otherwise), a scale is invaluable.
But yeah, once you have some something a few times and have the feel, you can convert to volumes and go based on your senses. There's a baseline science / formula to some cooking, but the rest really is art.
This feels like a nit, because really I am just glad to see someone else pointing out the obvious realities here. While I would be hesitant to try Mr. Slide Rule's cooking, I'd try your cooking without fear!
If you see a recipe involving flour and it uses volume, it is trash, will not be reproducible. All serious baking is done by mass and mass only, except for glazes / coatings and/or if a very specific product / brand is specified. EDIT: as another commenter here noted, yeast also does not scale linearly (obviously) except in special cases.
Also, oils in general should be measured neither by volume nor by mass, but relative to what they need to coat / submerge (be that an ingredient, a cooking surface, or some combination of the two), or, for deep-frying, based on the amount needed to not drop temperature too significantly for whatever batch you are frying. That is, much cooking is about surface areas of your ingredients.
People had to be taught not to go wild with the extra precision.
But, sure, I guess this helps you scale up those guidelines in some rare cases where that math isn't trivial to do in your head...
maybe the recipe calls for 80 g of butter but you only have 57 g
The amount of fat is rarely critical, pie crusts and puff pastry the exceptions. Unless the situation is puff pastry, make the full recipe. There are also recipes, like Better Homes and Gardens cookbook "baked rice pudding", that you can fudge ingredients to an extent, but can't double. The heat transfer of a double sized batch of custard prevents the whole thing from cooking.
The point being that food is more and less than chemistry. It's more and less than thermodynamics or heat transfer. It's art.
PS
I own 2 slide rules. I don't use either one in the kitchen.
Bakers percentages (measuring by-weight as a percentage of the largest mass ingredient (usually flour or water)) only work for lean dough and only for the non-fermenting components of that dough.
Put more concretely, one does not linearly scale the yeast in a lean dough. It results in far too rapid a fermentation, over-proofed dough, and less flavor complexity.
I'd never put them near my kitchen - too precious. Also, not necessary? Today I readjusted the measurements for a chemistry experiment by 50% without a calculation aid and it's really not that hard.
What? No way that happened! In all seriousness though I almost never find myself in the need to multiply anything in the recipe by the amount different than some multiple of 0.5 and these are pretty easy to do in my head.
https://www.sliderule.tokyo/products/list.php
Circular rules are superior to slide rules.