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Jun 13, 2014 10:45 AM

Imperial v. Metric issue

Hi all,
I just bought my first digital scale because I'm noticing more and more 'foreign' recipes on the internet that use the metric measurements and, more and more of us Americans are rolling over to it too.
Question is, should I convert all my personal recipes slowly over to metric over a period of time?
I know they would all be more accurate, but is it worth it?
I carefully scoop up my flour... how accurate is that?


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  1. YES YES YES!!!!!
    Please, PLEASE!!!!! convert to metric.

    It is definitely worth it. I've converted everything in my life to metric/Celsius. In my eyes it has simplified everything and makes conversions much easier. I especially like Celsius for day to day non-cooking use. It took a little bit to get used to but it wasn't ever a hassle.
    I always prioritize recipes which use metric, and weights rather than volumes or other arbitrary measurements.

    Yes, it will be far more accurate to use weight than volume.

    Edit: I'm American, and it drives me crazy America uses standard, among other things.

    18 Replies
    1. re: EatFoodGetMoney

      I agree 100%. I have changed all my recipes to read in both Metric and US standard, but follow the metric myself.

      Also, I never use by volume measuring for dry goods, only by weight.

      And I am starting to change over to by weight for liquid measure as well.

      1. re: JMF

        volume measure for liquids is used in pro kitchens and is perfectly accurate unless your eyesight is poor.

        unlike flour or different grades of sugar, water/oil/etc. will weigh the same.

        1. re: hotoynoodle

          Look at the recipes in books like Modernist Cuisine, etc.

          Different oils have different weights for volume. I have been getting really good results comparing weight to volume when replacing different oils. I use volume/weight calulators like this.

          I never said that I was just working in a home or restaurant kitchen. I work with a lot of other food and beverage applications.

          Due to thermal expansion, many of the liquid products that I work with have different characteristics and volumes at different temps. These are not items I use in home cooking, but in commercial beverage and spirits creation and production.

          1. re: JMF

            fair enough. most on here are home cooks, so i didn't mean to overstep your experimentation. thanks for better context.

            1. re: JMF

              But when does that difference matter? If the recipe calls for sauteeing in 2T of oil, should I adjust for density? Or in a 3:1 ratio vinaigrette? I can't think of recipe where that kind of precision is needed.

              1. re: paulj

                Of course it doesn't matter for small quantities, especially for sauteeing or a vinaigrette, where an accurate measurement isn't needed. But when working in very large batches, and trying to substitute different types of an ingredient, it works quite well. I think you just like to argue. ;-)>

                In molecular/modernist recipes it matters quite a bit, and many home cooks are very into molecular/modernist cooking.

                1. re: JMF

                  For the sake of arguing I'll say that "some," not "many," home cooks are very into molecular/modernist cooking ;)

                  Sorry! It really is a unique approach to cooking and not widely practiced outside a handful of restaurants.

                  1. re: Roland Parker

                    Maybe "some" by percentage, but "many" in actual numbers of folks cooking like that.

                    1. re: JMF

                      Statistics, please?

                      Sorry, couldn't resist ;)

                      Of all the people I know who are serious about cooking, which is quite a large number, I can't think of any who practice molecular cooking at home. And this is borne out by the scarcity of molecular recipes in cooking magazines, newspapers, cookbooks and even TV programs.

                      No doubt some adventurous people practice molecular cooking but their numbers are likely sufficiently small enough to be a moot point in any debate over metric versus volume based cooking.

                      1. re: Roland Parker

                        I include sous vide in the "modernist" category. And I know lots of folks who cook sous vide at home, and sear with a blow torch to finish.

          2. re: EatFoodGetMoney

            Fahrenheit is much more precise when measuring tempuratures compared to celsius.

            1. re: John E.

              No, the choice of units is irrelevant to precision. Precision depends on the quality of the equipment and the care with which it used.

              1. re: GH1618

                Check the number of gradients in C. vs F.

                1. re: John E.

                  still irrelevant. You can have a Fahrenheit thermometer that registers to the hundredths of a degree, and it will be more precise than a Centigrade thermometer that only has markings every 5 degrees.

                2. re: GH1618

                  I'm curious about what kind of cooking people are doing that requires accuracy to within a fraction of a degree C.

                  If you're doing something that requires high accuracy measurements, your measuring device will have appropriate markings. With decimal points if needed.
                  But if your measuring device is only accurate to within a few degrees, you can quote to 50 decimal places, but your accuracy will still be within a few degrees.

                  1. re: tastesgoodwhatisit

                    I use temps in fractions of a degree C for sous vide. Not a ton, but it does happen. More during experimenting, but it's nice to have either way.
                    Might be useful for candy making too.

                    1. re: EatFoodGetMoney

                      You beat me to it. Those are two examples that immediately came to mind.

            2. I understand America is one of only three countries in the world not to use metric. There's a reason why the rest of us generally use metric - it's just so much easier.

              Took a while to get used to the change but, now, when I come across one of our old recipes, I have to resort to an online conversion site. American volume measurements have always seemed, well, just a weird way of going about things.

              And, when I visit America and watch the weather forecast in Fahrenheit, I'm always thinking "how warm is that".

              10 Replies
              1. re: Harters

                We get Boston tv channels where I live (Nova Scotia) and it seems strange when there are fahrenheit temperatures put on the map of my province. I have no clue what it means either :)

                1. re: CanadaGirl

                  Just think of it as very accelerated global warming.

                2. re: Harters

                  When I was a teenager/college student, , I was a radio announcer and we gave the temperature in both celsius and Fahrenheit. I can understand that milimeter, centimeter, meter, might be more precise, but celsius is less precise than Fahrenheit.

                    1. re: sunshine842

                      I think what he's saying is that because of the smaller difference between the F degrees compared to C degrees, the F (whole numbers) can be more precise than the C (whole numbers). This is leaving out fractions.

                      While it's possible to have C in fractions, such as 17.2 degrees, for everyday use it's not commonly done. I don't think I've ever seen weather forecasts in C that included decimals.

                      1. re: Roland Parker

                        When your temperature is taken in a hospital, it will be to a tenth of a degree. It could be finer if they needed it, because temperature can be measured to a thousandth of a degree or more.

                        1. re: Roland Parker

                          Environment Canada reports temperature to a tenth of a degree Celsius. You have to go past the summary page to get it.


                    2. re: Harters

                      As a scientist I can really appreciate the Celsius/Centigrade scale for measuring temperature in the lab, 0C = freezing point of water, 100C = boiling point of water.

                      But for weather reporting I like Fahrenheit much better. Why? Because 0°F = god damn cold and 100°F = god damn hot. Feels much more intuitive to me than the range of -20C to 40C.

                      1. re: kmcarr

                        That's why the Fahrenheit range was set where it was. In the temperate zone, most of the time, the temperature is between zero and 100.

                        Most English units are similar in having been chosen for convenience in ordinary usage.

                        1. re: kmcarr

                          Difference in opinion (and experience) I suppose. For me, -40°C = too cold, 40°C = too hot (in weather terms). Meanwhile, in cooking terms, nice increments of 25°C give very useful ranges for the oven:

                          150°C, 175°C, 200°C, 225°C, 250°C. Almost the only settings I need - with the lone exception of 100°C for crème brulée and other such items.

                          I think that what's "intuitive" is all a matter of experience and cultural exposure. What you grew up with will usually seem the most intuitive, just as the language you grew up with always seems more intuitive in terms of how you express a new concept than a foreign language.

                      2. Scooping is an inaccurate measure, and the same baker can scoop 4 oz. one day, 4.5 another, and on still another, 5 oz. A "cup" of flour should weigh in between 4.25 and 4.5 according to various sources. The variance will cause different results in the same recipe, carefully followed, from one baking session to the next,

                        Much better to use weights. No matter how you get it onto the scale, the weight won't change.

                        3 Replies
                        1. re: mcsheridan

                          But how do you convert a recipe that uses 1 cup? Do you convert it to 4.25 or to 4.5. Or what if the recipe is currently working with flour that weighs 5?

                          If you are happy with the recipe as it is written, and aren't in the mood to test a conversion, then don't convert. It's that old, 'if it's not broken, don't try to fix' adage.

                          1. re: paulj

                            I'm not converting a thing; that's the OPs plan. I'm just addressing accuracy re: volume vs. weight. However, if I had to convert, I'd use 4.25 oz. as a starting point.

                            I agree with you; I have a scale now, and where weights are called for, I'll rely on that. Some older recipes that rely on volume measures? Well, I'm not throwing away my measuring cups.

                            I love how some of the newer cookbooks, including Peter Reinhart's TBBA, post both measures.

                            Even if I was going to convert from volume to weights, I'd probably stick with ounces unless there were an extreme need for precision.

                          2. re: mcsheridan

                            Not really. If the baker scoops the same way every time, it's the same measure, more or less.

                          3. Your scale also has pounds and ounces.
                            If you are happy with your old recipes why bother changing them? Scooping may not be the most accurate measuring method but it is fast and for making things like pizza bread dough I have to adjust water amount anyway.

                            A scale is nice to have especially when you learn the tare function. The metric system is no more accurate, it is easier to convert measurements but how often will you do that? You have a kitchen not a lab. Measurements can be by the pinch or shake with very few disasters.

                            20 Replies
                            1. re: divadmas

                              United States, Liberia and Myanmar are the only countries in the entire world, maybe the entire universe that do not use the metric system. That in itself says that logical thinking people believe the metric system to be more accurate and easy to use.

                              1. re: genoO

                                In what way is the metric system more accurate?

                                For some cooking tasks using weight instead of volume measures is more consistent. But that's not the same as saying metric is more accurate. There are metric volume measures (L, ml), and there are American weight measures (lb, oz).

                                Boeing still uses the American units, while GM is all metric. Does the construction of a car require more accuracy than the construction of an airplane?

                                In a sense, the difference between GM and Boeing explains why the USA has not switched (on a national level). GM is an international company using suppliers from around the globe. Boeing is the biggest player in its market, and has a lot of control over its supply chain, and maintenance network.

                                1. re: paulj

                                  The Boeing 767 was the first all-metric US airliner.

                                2. re: genoO

                                  The fact is that the metric system is used a great deal in the United States. The difference is that in the US we do not compel the usage of one particular system everywhere. There are many examples of this, but to cite just one food-related example: If you order a beer on tap in a bar, it will likely be served in a glass of 12, 14, or 16 fluid ounces (US), but if the beer is imported, it may be served in its own glass marked in ml (typically 500). Nobody is confused by this. Nobody objects to this. Americans aren't nearly as metric-phobic as Europeans make us out to be, now that the government has stopped trying to force us to convert.

                                  1. re: GH1618

                                    Most wine comes in 750ml bottles, even when produced in the USA. I heard on The Splendid Table that this is roughly the lung capacity of a glass blower.

                                    A lot of beverages come in 'rounded' ml sizes, e.g. 500 ml bottles of water.

                                  2. re: genoO

                                    The use of metric units has nothing to do with accuracy. Any system of measurement is as accurate as any other, when applied as diligently as necessary to achieve the desired accuracy.

                                    1. re: GH1618

                                      Not when temperature is concerned.

                                    2. re: genoO

                                      China, Indonesia, India, Hong Kong, etc, etc use the metric system. Most of their stuff is still crap. Give me a U.S. made Imperial product any day.

                                      1. re: Antilope

                                        The US does not use Imperial units. We use US Customary units, which are not the same.

                                        1. re: Antilope

                                          units of measurement have nothing at all to do with product quality.

                                          I'd be quite interested to hear the reaction if you were to tell some of Mercedes Benz' or BMW's top-flight engineers that their stuff is crap because they use the metric system.

                                        2. re: genoO

                                          I'm quite "logical thinking", and I don't think the metric system is any easier or more accurate. This is a little like the argument that I should like soccer -- because it's foreign and therefore better.

                                          1. re: jmckee

                                            Its definitely more consistent. Measure a cup of flour and weigh it. Do this 5 times. You'll get a different result every time. They may differ even by 25%. The weight of a cup of four differs as you change brands. Take White Lily Flour. When a recipe calls for a cup of flour, they recommend you add 2 more tablespoons a s acup of White Lily is lighter than a cup of King Arthur. When you weigh, it just allows for much more consistent results.

                                            1. re: GOJIRA

                                              Your example has to do with weight vs. volume measurements, not metric vs. US Customary units.

                                              1. re: GH1618

                                                The original post seems to be comparing weight and volume (op is asking how accurate just scooping flour with a measuring cup is hence my post) I dont think op was comparing oz. vs. grams from the way the question was worded.

                                                1. re: GOJIRA

                                                  Yes, and you are both muddling up the two issues.

                                                  1. re: GH1618

                                                    I think we're lost in translation lol.

                                                    While the title seems to be addressing the differences between the metric system and the u.s. customary system, it is clear that op meant to ask about volume vs. weight and only titled it that way by mistake. Just an error in the title. We're human but its easy to understand what the actual problem was here. My post has to do with the actual issue op was having.So to be clear, my post has nothing to do with comparing different official systems of measurements. Didn't mean to muddle the two issues together.

                                                    1. re: GOJIRA

                                                      The OP question was whether it was worth converting personal recipes to weights. The OP is already careful with flour (where the weight v volume issue is clearest).

                                                      Let's say he has a recipe that works well now, and he converts it using values from some print source - and the converted values don't end up matching what he's been used to doing. e.g. his scooping produces 110g/c flour, and he uses a 120 g/c conversion factor. The new 'metric' recipe will end up being consistent and repeatable - but consistently wrong.

                                                      1. re: paulj

                                                        But if it were noticeable "wrong," the cook would adjust the recipe until it came out right, not repeat it.

                                                        1. re: GH1618

                                                          It can be VERY hard, without a comprehensive knowledge of cooking theory and food science, to adjust a recipe in the wake of change of measure, in order to replicate previous results, if your measurement technique in the past was approximate. The problem is that you have too many variables (each ingredient is a separate variable) changing out from underneath you, and to adjust the recipe, you'll have to change only one at a time; this could be a lengthy process and it may not be obvious when it's right because the adjustment may have been made perfectly for one ingredient but still not right for another, and then identifying when to stop changing the measurement of the one and start experimenting with the next is difficult.

                                                          Also it should be added that this assumes that the intended result is known. It can well be that a person comes across a recipe, tries it possibly with some conversions and thinks the result just fine, when in fact it actually is quite different from what it was supposed to be like - or the converse can be the case, the end result can seem unappealing to the person who tried it, and it may not be clear whether that's because the result achieved was what was intended by the original recipe designer, the recipe was poor, or the measurement conversion was off.

                                                          There are other strange effects. Some years ago I helped a person struggling with a chocolate mousse recipe that came out terribly for them every time. It turned out that the problem is that they were trying to downscale a recipe that made a fairly large quantity into one that made a quantity adequate for two, and you just couldn't do it with the way the recipe had been developed and the techniques that were being used. Indeed, not all recipes are amenable to downscaling, period. Roasts can't usually be effectively downscaled from a certain minimum size because they rely on reactions that need a certain mass of meat. Etc etc.

                                      2. using a scale for recipe ingredients will produce accurate results, regardless of whether or not you use metric. however, trying to measure solids, like flour, with cups is NOT accurate. weights will always be best.