What formula switches from pints to milliliters?

Factual Questions
41

Where I live, large and extra-large are the most common sizes.

Egg sizes make a difference in baking, and in making hard-cooked eggs. Precision in measurement is more important in baking than in other types of cooking. Good baking books usually specify large eggs, and good bakers will use them. For hard-cooked eggs, it takes longer to cook a jumbo egg to a particular degree of doneness than it does a large egg.

It’s true that the sizes vary some. From a practical standpoint, this has the same effect as there being limits to precision in measurement. It doesn’t matter as long as things are close enough. When making a cake, for instance, the difference in size between large and jumbo eggs is significant, while the variation between large eggs is usually insignificant.

The main point I was trying to make, though, is that there is such a thing as half an egg. If you have a recipe that calls for three eggs, and you want to make half of it, you can do it. An egg isn’t an atomic unit in cooking.

42

I’ve been trying, but your mom won’t put down that shotgun.

43

I was completely wrong. I need my vacation

44

Hooray for Wikipedia

Imperial pint 568.26125 millilitres (exactly) ≈568 ml
United States liquid pint 473.176473 millilitres (exactly) ≈ 473 ml
United States dry pint 550.6104713575 millilitres (exactly) ≈ 551 ml

45

your sentiments are admirable, but utterly misguided. And evidence of a certain OC point of view.

The input recipes you’re working from are all full of grossly rounded off values.

Taking a ballpark estimate and multiplying by a conversion factor with 10 sigfigs results in garbage, not a usefully precise number.

When you see a recipe which says “1 cup flour”, you need to understand it actually means 1 cup +/- 1/4 cup. So your converted result number should also be the roundest value available within about 25% of the precisely converted number.

One can bicker about whether the tolerances are plus/minus 10%, 25%, or 40%. For baking some, but not all factors are probably nearer 10%. For most nonbaking

46

(Hit Enter too soon) …

… uses 25% is plenty close enough. For some ingredient mixes, eg vegetables in a stew, 40% is ok.

Do your readers a favor and embrace rounding to the nearest 25% and skip all the rest of the longwinded details. They’ll be much happier and so will you.

47

Yeah, I agree that some chickens can produce Jumbo. However, for the average home kitchen, the “Large” egg is probably standard.

However, I’ve been cooking for so many years I can use eggs of various sizes and just tell if I need to add another one.

48

I think it may be useful for you to review the concept of false precision and significant figures.

49

That’s the whole point. This is a situation where the precision isn’t false.

Whether the precision is useful is irrelevant.

50

LSLGuy, your post is great.
Your formatting, however,
makes me think of a line printer

that is really, terribly, horribly
out of adjustment.

51

No, he just didn’t say why he needed such accuracy…
In fact he was asking how some other source could provide such accuracy, so as to not be seen to be inferior.
Of course he found out there are different cups, and different government declarations of what a modern cup is… eg in Australia, the cup is still used in cooking, and its defined as 250 ml.
Technically, in units capitals are reserved for peoples names. There is no Mr or Ms Litre… Watt ? James Watt. Newton , Sir Isaac… Pascal ? Blaise… Joule , yep Mr Joule.

And in prefixes, its m for milli and M for Mega.

52

I wrote that on my phone using Tapatalk. Each time one edits a post with that app, it apparently converts the CRs to CRLFs. Which vBulletin then converts to CRCR. So at each edit cycle the paragraph spacing increases. The same thing happens when a post is quoted, so that part starts out double-spaced even on the original post submit.

I usually try to go back and edit all the excess CRLFs out. But I was pressed for time and wanted to fix the content problems first.

I agree it’s annoying and before I’d started using Tapatalk I’d noticed a few other posters who habitually have excess paragraph spacing, and wondered what’s wrong with them. Now we know.

Tapatalk also includes my sigline whether I want it or not. I usually reserve it for posts where it’s relevant to the post content, which it certainly wasn’t this time.

Oh well.

53

IMO he asked two related but different questions.

The first was the one in his title, the specifics of (US) pint to milliliter conversions and the provenance of 253.{many digits of fraction}. Which was ably explained by others as the resulting fraction from chaining several infinitely precise conversion factors. And with which I agree, but made no comment on.

Then he went on to talk about his larger goal, recipe conversion. Wherein he was wrapped up in the importance of precision. Far beyond the precision (not accuracy) of his inputs. *That *was the part I was addressing and debunking.

I wonder if we’ll ever hear from him again?

54

LSLGuy, I appreciate all your help, including your psychological diagnosis, but I want to make sure you saw the second paragraph of mine of 9/24/2015, viz.,

“With regard to the unnecessary precision, I see now I should have explained yesterday (when it seemed like TMI) where these paragraphs will appear, which is only in a free spreadsheet that accompanies the cookbook, in a text box headed something like, “In Case You Care.” I prefer to use full precision in these circumstances, even though I know such precision is useless to cooks, for two reasons. The main reason is that it allows users to check my math (or theirs). A secondary reason is that full precision allows users to see at what decimal place, if any, rounding error kicks in.”

As you can see, this extreme precision applies only to the spreadsheet. It does not appear in the recipes, which are all in U.S. traditional units. For that matter, for those U.S. units the spreadsheet allows answers only up to either one or two decimal places or 1 or 2 digits in fractions. Metric units are shown to the nearest thousandth of a liter, the nearest hundredth of a deciliiter, and the nearest whole mL.

You say, “Taking a ballpark estimate and multiplying by a conversion factor with 10 sigfigs results in garbage . . . .” I disagree that it’s garbage. It’s a pointlessly precise but still accurate number, which is the opposite of garbage. Multiplying by a random number would produce garbage. Multiplying by the reader’s Social Security number would produce garbage. But multiplying by the correct conversion factor, no matter many decimal places it has, does not produce garbage. Indeed, the number it produces is the best possible number, and no other number is better.

I don’t understand how to implement your suggestion to round off to 25% or so. If a recipe calls for “1 cup of molasses,” should I change it to “3/4 to 1 1/4 cups of molasses”? Should I change it to “1 cup of molasses, plus or minus 25%”? One reader’s dish might turn out 50% more molassesy than another’s, and I’ll bet at least one of them would be unhappy. I’ve never seen recipes written this way, and I don’t plan start a trend.

And if you meant to refer to the conversion spreadsheet, not the recipes, are you suggesting that if the user wants to know how many mL are in a cup, the answer cell should be “177 - 296”?

So, again, I don’t understand how to implement your suggestion to “Do [my] readers a favor and embrace rounding to the nearest 25%.” Can you explain in more detail, LSLGuy, what specific changes you recommend? Thanks.

55

Assuming a 25% slop factor which is a bit generous and certainly is dangerously sloppy for baking …

I’m suggesting that if a recipe calls for a cup of something and you’re converting that recipe to metric, then *any *value between 177 and 296 is *equally *valid. (I’ll explain why below) So you should apply a rounding algorithm that says “What’s the easiest nice round number in that range?” and display that. I’d suggest 250 would be a good choice in this case (although 200 wouldn’t be a wrong choice).

With a big slop factor like 25% I’d encourage you to gently bias all your roundings in any given recipe the same way, either up or down. That prevents things like 24% too much water and 24% too little sugar so the goop doesn’t set properly. If everything rounds generally upwards the user just ends up with a bigger recipe.

Having said all that …

A more realistic rounding factor is 10-15%. I originally wrote 25% mostly to shake you out of what I perceived to be an inappropriate attachment to precision for the heck of it.

Why do I say precision is wasted & misguided? Why do I say that 1 cup is really 3/4 to 1-1/4 cup? Because it is. I agree a typical US-origin recipe is written like “use 1 cup carrots”. But they actually mean “use *about *1 cup carrots”. Unlike in engineering, the tolerances aren’t usually explicitly stated. But they’re there.

As an experiment, take any non-baking recipe and make a batch but increase only the first ingredient 25%. It’ll be fine. Do the same thing with the second. Same result. Whoever *wrote *the recipe did a bunch of rounding in the process of writing down what they’d done by guess and by gosh a few times to “perfect” the taste & texture to their idea of perfection. Somebody else’s idea of perfect taste and texture will have different roundings. In the absolute, they’re all about as good as the other.

If you still don’t believe me, go buy online and buy a cookbook written and published wholly in a 100% metric country, e.g. Germany, Italy, France, etc. Not one of the Commonwealth countries that are officially metric, but still have one foot in the customary system.

You’ll notice that all the metric measurements are nice round numbers. If you apply your infinite precision conversions to yield customary US units you’ll produce a very fussy & difficult-to-measure recipe. So round everything off to the nearest quarter-cup or whatever. It still cooks & tastes fine.

In fact it’d be especially informative to locate recipe books such as “French cooking for Americans” and “French cooking for Germans”. Between the two you’d find a lot of dishes in common but each adjusted to nice round numbers in the two different measuring systems. It’d give you a feel for how much rounding is commonly done by professional cookbook writers/editors for various categories of recipes.
I could go on about the vagaries of density of granulated or powdered ingredients and the hugely varying densities of chopped or diced ingredients. But this post is already too long.

Yes, I did pick up in this paragraph in your earlier post and the one just above:

It was the last sentence that caught my eye. Rounding error of about 1/2 a sigfig “kicked in” before the original recipe was put to paper. The info you expect the user to derive from your precision was lost before the original recipe was written. It can’t be recovered by multiplying by a “better” constant.
My bottom line:
When I tell you “it’s about 500 miles from City A to City B”, you don’t get a better answer by restating that as “it’s about 804.672 kilometers” versus “it’s about 800 kilometers”. Or even “it’s about 750 kilometers”, since you have no idea which way or how much I rounded my actual measurement to get to my “500 miles” figure.

56

Late add: Good luck with your project. I wish you well. I hope I don’t come off as an angry curmudgeon. That’s not my POV at all.

57

I’ve seen measuring spoons that go down to 5 ml. I can’t imagine anyone who’s just cooking needing a pipette for more precise volume measurements.

58

LSLGuy, I guess I’m still not being clear. The recipes themselves use only U.S. traditional units such as pints and tablespoons. They do not ever list any metric units, and they never will. The only place where metric units appear is in part of the spreadsheet whose explanatory paragraphs are what I’d like checked for clarity and mathematical accuracy.

I still don’t understand what specific changes you recommend, if any, either to the recipes or the spreadsheet.

Finally, I disagree with you that “about 750 kilometers” is just as good as 804.672. As to the decimal portion, I already agreed that it is unnecessarily precise, but nowhere in the recipes or elsewhere in the book do I even suggest that a cook use such precision, and even the conversion spreadsheet does not offer such precision.

But I also disagree that 800 km is no better than “about 750 km.” 750 is 6.25% less. By using such rounding you have introduced significant and unnecessary error.

If I tell a third person that the distance is “about 750 km” and that person translates it correctly into 466 miles and then reduces it by that same 6.25%, the result is 437 miles, which according to you is just as good as 466. If 750 is as good as 800 and 437 is as good as 466, then 437 must be as good as 500, which it isn’t. You can see that by the time a fourth and fifth person have gotten involved, either City A is going to have to pick up its streets and buildings and move or City B is.

LSLGuy, it is precisely (ha) because one cannot predict in which direction any rounding takes place that one should not round much, if at all. If the original estimate was 500 miles then 800 km IS a better answer than 750. Or 850. And it’s rounder!

For many years I examined the books and other documents from funeral homes across the U.S and Canada to assess their value for sale or estate taxes or divorces or whatever, and almost always I requested a real estate appraisal. And almost always the appraiser applied rounding at the very end, where all the various real items’ values were added up. If the actual total was $1,000,435, it would be rounded down to an even million, a difference of only 0.0435%. I think this was the appraisers’ way of saying what you’ve been saying, LSLGuy, which is that either number is a guess. I always used the unrounded total in my own list of the firm’s assets, and I explained why, which is that such rounding is unfair to one party or another, in this example the seller. Would you be willing to give up $435 because someone decided to round up or down FOR NO REASON? At the end of each such valuation report I showed the total value of the several net assets for sale down to the exact dollar, because I could think of no reason not to, because any gratuitous rounding would work against one party and for the other. I went on to explain that the last few sigfigs would be overwhelmed by many other factors, but I still stuck to the original, unrounded number because NO OTHER NUMBER was more accurate. Can you tell me how this example is different from your examples?

I ask yet again, what do you think I should change in the recipes themselves or the spreadsheet?

Although all of the above has been directed only to LSLGuy, I want to report to everyone reading this thread this far that I finally realized, thanks to Saint Cad, how to simplify the formula for converting cups to millimeters, which was (231 / 16) * (2.54^3). By switching to gallons instead of cups for the gospel number I was able to eliminate the whole division by 16 step to get cups per gallon, so now it’s simply 231 * 2.54^3, where 231 is the number of cubic inches in a gallon and 2.54 is still the number of centimeters in an inch and where 1 cc = 1 mL.

Baffle, yes, you get it, and you said it better back on September 25th than I have so far, and certainly more short-windedly.

I’m still happy to upload the Excel 2010 spreadsheet to anyone who wants to see it and, ideally for me, criticize it.

59

BioTop, it is true that the conversion has no false precision. But the output if you do not round properly, as the input has finite precision. I believe it is standard to round to the 10s of mL, though I could see rounding to the nearest mL.

Your conversion factor can be as precise as you want; however, I’m not sure that people who see it would appreciate the extra level of precision, when it almost certainly would not change the calculation at the level most cooks would use.

That’s not to say that the OP shouldn’t show the full conversion process and the precise conversion factors–that depends on his audience. But he absolutely should not include false precision the recipes proper.

If something calls for 1 cup of water, give it as 237 or 240 mL.

60

And I just realized I read Baffle’s name as BioTop. Appologies.