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.
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.
In metric countries, a small kitchen scale is very common. The US seems to run on volume, rather than weight.
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??
Anyway, it's not really an issue.
This is why any half-ways sane baker works off a scale.
Also, not all ingredients in a recipe scale linearly--most notably spices, tinctures, and any fermentation components.
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.
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.
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.
JohnFen•1d ago
> 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.