Historical cooking measures and the metric system

 

“The Sifter” welcome page.

I recently came across an article in Atlas Obscura that highlighted a new site, called The Sifter which, according to the article:

 

 

 

 …is a catalogue of more than a thousand years of European and U.S. cookbooks, from the medieval Latin De Re Culinaria, published in 800, to The Romance of Candy, a 1938 treatise on British sweets.

This got me thinking about how we take precise measures for granted in our current cookbooks. If we look back, specific amounts of ingredients are a more recent development.

Based on my preliminary research, even by 1796 recipes had some measurement references. However, when I started looking at older recipes, the “amount” gaps became apparent. For instance, from The Commonplace Book of Countess Katherine Seymour Hertford (1567), you get things like:

Take a quantitie of barlei well rubbed & clensed wth a faire cloth from all dust & boile the same o[n] the fyar wth a good quantitie of faire water in a new earthen pot lettinge it seath till the barlei…

But even in this 1567 reference, there is mention of pint and gallon units:

Distel a pint of the water of everie of these by them selves and put to them a gallon and a pynt of good malmesei… [Note]

 

Back when ingredient lists were sequential and basic

While I didn’t research exhaustively enough to find the exact dates of when measures were routinely included, I can tell you one of earliest sources (1340) referenced on medievalcookery.com, has ingredients, sans units, listed succinctly as:

Almond milk, rice flour, capon meat, sifted ginger, white sugar, white wine; each one in part to be boiled in a clean pot, and then put in the vessel in which it will be done, a little light powder; pomegranates planted thereon.

How much of each? Who knows? According to a 2017 article in The Atlantic, cookbooks from the 1400 and 1500s were more memory aids for chefs in the world of the royals, rather than “how-tos” for common folk so measures weren’t missed.

Out of curiosity, I started poking around in The Sifter database for some recipes and when I typed in “measures,” I came across, for instance, Seventy-five Recipes for Pastry, Cakes, and Sweetmeats from 1832. Clearly, measures needed some definition at even this late.

From the above-mentioned cookbook.

That’s old-fashioned cooking for you.

What does this have to do with the metric system?

I dare you to try to sell a cookbook today without including measures. People would go crazy.

The trouble is 95 percent of the world doesn’t know what our U.S. customary units are. Therefore, drawback number one: Our cookbooks will only sell overseas to people willing to take the time to convert units to the metric system. (A poor strategy from an international distribution standpoint for any printed versions.)

From a sausage cookbook.

Some cookbooks try to get around this by printing ingredients down a center column with quantities to the left and right. While that works, why do it at all?

If everyone was using the same units (metric) it would make it our lives much easier and people wouldn’t have to worry about the current differences between the U.S. and U.K ounce units, for instance. (See photo below.)

Note the difference in volume between the U.S customary and U.K. ounces. Ours is bigger!

Drawback number two: Scaling recipes up and down becomes MUCH more difficult with our three teaspoons to a tablespoon and eight ounces to a cup business. Since the metric system is based on tens, scaling up and down is much easier.

Drawback number three (of those that immediately jump to mind): We use volumetric measures in this country, with our teaspoons, tablespoons, cups, and so on, and these can cause all kinds of problems as I cite in an earlier post. With the metric system, you use a liquid measure for liters (and fractions thereof) and a scale for mass in kilograms and its fractions. That’s it.

Let’s consider just how difficult we’re making things for ourselves and pick a more sane path moving foward.

More exciting posts are in the works. Please stay tuned.

Linda

Note: While I couldn’t find a definition for “malmesei,” it turns out “malmsey” is a sweet, fortified wine. That would make sense in this context with a liquid measure cited. I’ll leave it to you to look up the other confusing ingredients.

A liquid measuring cup and the metric system

This was really difficult to photograph since the units (cups and ounces on one side and milliliters on the other) are only embossed. Most measuring cups use ink for contrast. Hopefully, the visual complexity of one side compared with the other still comes across.

Every once in a while I come across something that really lives up to the cliché of “a picture is worth a thousand words.” I thought I’d share the images above with you since it relates directly to our lack of metric system adoption.

Most glass measuring cups are fairly cleanly designed to show U.S. customary units on one side (no, we don’t use the Imperial units we originally brought over with us from the U.K) and those of the metric system on the other side.

However, the one I recently bought really puts our awkward system into full light.

Interestingly, when I pointed my find out to the person at the cash register, she indicated that she wanted one as well. Alas, as I was shopping in a discount store, I had to inform her that I was buying the only one I saw. (Frankly, I was pleased that someone else wanted something that I considered a fairly unusual item.)

Keep in mind that the whole point of having liquid measuring cups is to avoid spilling whatever one wishes to measure. In theory, the volume-based measure of, say a cup that can be leveled off at the top containing dry ingredients, should be exactly the same as for a liquid measure. The only reason for a liquid measure is to prevent spilling once the measurement is made.

Americans have both “dry” and “wet” measuring cups is so, if you need a full cup of a liquid, you don’t spill it. A liquid measuring cup provides “slosh” margin above the full-cup measure. Also, liquids tend to level themselves. “Dry” cups makes it easy to push off any excess material and make it level. That’s why you don’t normally see half and quarter cup measures listed within dry measuring cups—you couldn’t level them. [Note the ml printed on the dry measuring cup.]

Once I decided to write a blog post about the measuring cup posted at the top of the page,  I tried to do some more research to find out why the designer veered off toward visual complexity for something that is usually designed with simplicity in mind. Unfortunately, I was unable to find out much more from the paper price tag on the bottom of the cup, but it indicated that its origin was Turkey (even though, according to the U.S. Metric Association, Turkey adopted the metric system [or SI as it is known by most of the world] back in 1930. So apparently the cup was intended only for the U.S. market.

There was no identifiable marker’s mark other than something that looked to me like almost a ying and yang mark. A mystery to me, but if someone else can shed light on the maker so I can get some more background—preferably in English—I’d be happy to hear it.

Thanks for reading,

Linda Anderman

Time wasted without the metric system

When I talk to people about a future where we switch over to the metric system, many  bemoan how difficult the change would be. The problem with that perspective is that most people have no idea how much of our time is wasted due to our using U.S. customary units. I’m highly confident that after a few months of using just metric units, our response would be: “What were we thinking? Why didn’t we do this ages ago?”

Ounces made it into two top 10 questions for recent Google searches.

Just last week I came across an infographic titled “10 Most Asked Questions on Google.” It included queries searched for during a previous six-month period and was global in nature. The graphic belies the assertion that Americans understand their current system (“So why go from something we know to something we don’t know?” they ask me). Bottom line:  Because questions eight and 10 are about how many ounces there are in a cup and a pound (respectively) so we really don’t know our units, despite what we say. (Money amounts refer to the cost of ads on the answer landing pages.)

Between the two of them, they accounted for 900,000 questions in that six month time frame. So how does that play out? Let’s say you’re working in the kitchen and you decide you want to scale a recipe up or down and need that “How many ounces in a …?” question answered. The first thing I’d do is search my memory bank to see if that was something I already knew. Then, if I didn’t know, or was less than confident in my answer, I’d need to either whip out my phone or mosey over to my computer to get the answer.

While the actual Google search might seem almost instantaneous, the process of getting to enter the question is not. Let’s say that it takes about 90 seconds before you get to the Google search part (I have nothing to back this assertion up but it is probably conservative). If so, that means we (and by “we” I mean either Americans or the poor souls who find themselves confronted with our crazy units here or elsewhere in the world) spend 45,000 hours each year searching for this information. Put another way, every year we spend more than five years of our time reminding ourselves how many ounces there are in things.

This amount of time, of course, doesn’t include all the time spent looking such information up in a cookbook only to discover (in most cases) that conversions between metric units are sometimes included but not how many ounces, for instance, there are in things.

Most cookbooks include units between U.S. customary and metric system, not within customary units.

I can’t confidently promise that we’d likely spend any saved time on something productive but at least we’d have the opportunity to spend it on something less wasteful.

Confusion in the kitchen

Our units make scaling ingredients very difficult

As if that wasn’t bad enough, I also recently came across the cheat sheet on the right.

It’s just nuts that we put ourselves through these machinations when using the metric system is so easy. Unless you’re really slow, you wouldn’t even need such a chart.

1/4 liter    =     250 mL
1/3 liter    =     333 mL
1/2 liter    =     500 mL
2/3 liter    =     666 mL
3/4 liter   =      750 mL

Given that we already use decimalized currency, most everyone could immediately tell you that half a dollar is 50 cents and a quarter of a dollar is 25 cents without a calculator or a Google search. It’s the same with metric system mesures.

While it might take some thought and effort to switch over to the metric system initially, once there, our lives become a whole lot simpler.

If only more people knew. Help spread the word please.

Thanks,

Linda

Alton Brown and the Metric System

I have previously written about how the Food Network’s popular chef Alton Brown has praised the ease of the metric system for kitchen use as far back as 2012 in my post called Not the End of the World:

It is impossible to measure these ingredients with consistent accuracy by avoir dupois—that is, volume. Heck, I’ve seen a cup of flour weigh anywhere from 3 to 6 ounces. If you want to measure flour, you have to do so by weight. End of story.
I’m Just Here For More Food, Alton Brown, p. 14.

But, bless his little Southern heart, in his latest book, Every Day Cook: This Time It’s Personal, he’s taken things a step further:

Despite the grumblings of my editor, I’ve decided to quantify these recipes the way I do in real life…For instance, I combine weights (metric no less) with standard volumetric measurements, that is, tablespoons, in the same recipe…However, when I do weigh, it’s always metric because…I hate fractions. I also hate working with decimal points, and that’s the nice thing about grams. No one ever says 18.4 grams unless they’re weighing out something that’s controlled either by local/state/federal laws or by international treaties. Now, I know that there of you who say food isn’t worth the trouble of purchasing a decent, multiformat digital scale with tare function (allows weights to be zeroed out), but you’d be flat-out wrong.

Of course, I could quibble with the fact that the metric system is based on mass rather than weight (weight varies by the gravity of the planet you happen to be on—mass is mass, regardless), but I suppose he could quibble back our scales actually go by a weight equivalent of mass—and I couldn’t prove him wrong.

There are lots of scales on the market. Pick one that catches your fancy to start with.

But here’s the important bit: not only is he urging cooks of various persuasions to buy and use a scale in their kitchens (you can’t consistently use the metric system without one, and very few people have a proper kitchen scale), but he also includes recipes that are based on metric units!!!!!!!

For instance, his recipe for Always Perfect Oatmeal includes 120 grams of rolled oats, 25 grams of quinoa, 475 grams of water and 7 grams of kosher salt. Yes, he does provide a couple of those ingredients with U.S. customary equivalents but for the quinoa and salt, he does not, thus forcing the use of a scale or a conversion. Where there are conversions, there will be conversion errors so hopefully those with the mistakes will see the error of their ways.

I urge you to take advantage of the coming holiday season to 1) buy lots of copies of Alton’s book for those you love; 2) and buy them a scale to go with it to get folks familiar with weighing things in the kitchen. Then, when we do convert to the metric system, more people will be ready. Tell you what, if this post gets more than 2,000 views before the end of the year, I’ll make a short video showing just how easy a scale is to use for cooking.

A couple of words about kitchen scales

Three years ago I wrote a post called Someone’s in the Kitchen with the Metric System where I extolled the benefits of using scales in the kitchen. While Alton said something about getting one for under $100 (yikes!), most of the ones I’ve bought for the kitchen and demos are between $10 and $15 each and—when I checked them against a calibration standard they do a respectable job all the way down to a gram.

In the post I put up a few years ago, I also pointed how there are some very cool scales you can get to present along with his book. Hardcover is currently $23.57 from Amazon. Throw in a scale for another $10 and you’re good to go. Buy a nifty scale like the one above and bump the package price up by an additional $20. Hey, do whatever best suits your gift-giving needs.

However, I do urge you to buy and use his book to support someone brave enough to include metric system units in an American-based cook book that also supports my work by getting people familiar with using scales in the kitchen. Every little bit helps and this is more than a little bit!

If I loved him before (and I did), I love him even more now.

Also, do let him (and his publishers) know that you support his use of metric system units through social media by using #EveryDayCook along with #USAgometric.

Thanks!

Linda

My Metric System Demo at the Los Alamos Science Fest

Los Alamos Science Fest was Saturday

On Saturday I spent four hours talking up the metric system at the Science Festival here in Los Alamos. Specifically, I was trying to help people understand how much easier the metric system is to use in the kitchen. Rather than having all those volumetric cups (and a half, and third and quarter) and tablespoons and teaspoons (and all those fractions down to an eighth) you really just need two things: a liquid measuring cup and a scale that measures in grams (most electronic ones can convert between different units).

Not only is a scale a more precise and consistent measure in the kitchen, it’s also easier than what we’re used to in this country. Since we don’t use the metric system here, most people have no idea how handy a scale can be in the kitchen. I wanted to show them.

Here’s what I did:

I asked if people were willing to take a metric challenge. (There were a lot of children there and almost all of them were game to give it a try.)

Toy coins worked well for the demo since they don’t fit neatly into the cup

I then gave two participants each a one-cup measuring cup and had them measure a cup of toy coins (I wanted objects that would not fit neatly within its area). When they were done, we put the cups on scales to how closely they measured in grams. In some cases, even when the cups looked like they had the same amount in them, the mass varied usually by around 5-7 grams but throughout the day I saw measures all the way from 30 grams up to more than 100. That’s quite a difference!

While the they were measuring, I told the adults, or other observers, some of my points about wasting our kids’ time in schools by teaching them a complicated system that no one else uses. I also pointed out only needing two things to measure with saves space and hassle in the kitchen.

Using the metric system, all you need is something to measure wet and dry ingredients (left) instead of the stuff we have to keep track of now (right)

Once that was done, I showed the parents how easy it is to measure ingredients right into the bowl and bypass dirtying all those other measuring cups and tablespoons we currently have to deal with.

I also talked about something that happened to me not too long ago when I had a recipe that called for a cup and a half of brown sugar. Not only do you have to pack the brown sugar to get the right amount, I also debated whether I wanted to wash a spoon (to dish out the sugar) and two measuring cups or a spoon and one measuring cup but have to pack it three times. In the end I decided I didn’t want to do either and looked up how much brown sugar that would be in grams. Then I put the bowl I was using on my scale, zeroed it out using the tare function, and then measured that amount directly into the bowl. In the end I only had to wash a single spoon.

In addition to the demo, I had a primer (Cooking in a metric kitchen (pdf)) on using scales in the kitchen. While many sites don’t include metric measures, several do including the wonderful allrecipes.com (though it takes an extra click to make the conversion). I also had a hard copy of the Metric Maven’s metric cookbook along with its link and the source for a metric chocolate chip cookie recipe from the National Institute of Standards and Technology. If you have additional sites or references to assist with metric cooking, send them to me at milebehind@gmail.com and I’ll share as appropriate.

Also had an opportunity to reconnect with Dave Schwellenbach who had the booth next to me with his Kraz-E-Science demo. You can check out his website here.

More blogs are in the works. Thanks for checking in.

Linda

The MidSchool Math Conference

The next MidSchool Math conference is already in the planning stages

My presentation on Math and the Metric System: Using What’s Easy at the MidSchool Math conference went very well. The session had 50 people registered and while not everyone showed up, most folks did. Since the attendees were mostly math teachers I felt I had an opportunity to get them thinking about the metric system in new ways that they could take back their classrooms and hopefully their lives. The group was receptive and had lots of questions for me. They were also able to interact and ask each other questions about their metric classroom experiences.

Hands-on opportunities

I had scheduled some hands-on exercises using length and mass to help them get used to applying metric units. While length didn’t present much of a problem, only a couple of people used scales in the kitchen. This gave them a chance to play with some of the equipment I brought. (Let’s face it, pretty much every ruler and tape measure today has both U.S. customary and metric units on them but most people are so familiar with measuring cups that it doesn’t occur to them to use a scale in the kitchen though it’s far easier.)

I also brought some metric-only rulers supplied by the National Institute of Standards and Technology (centimeters on one side, millimeters on the other) and they cleaned me out of those—which I consider a good sign.

Avoid conversions!!!

A couple of folks on the U.S. Metric Association (USMA) listserve who communicated with me prior to my talk wanted to make sure that I didn’t encourage conversions during my presentation. Not only was that explicit in my presentation—twice no less—but I also pointed out that I’d gotten that feedback from USMA to try to drive the point home. I think it worked.

After all, the metric system was introduced at a time of widespread illiteracy and even unschooled french farmers and tradesmen learned it easily enough. It should be a cinch for today’s high-tech Americans.

One attendee told me she thought it was the best presentation she’d seen so far (I was in the afternoon on the second day) but I have to say that the keynote speaker on the first day, Dan Meyer, was extremely good. He stressed the need to engage kids studying math in the classroom in three acts and bring them along for a story where they really want to figure out what happens. Let’s face it, everyone gets more interested if there’s a good story involved. I think the audience heard him.

Testing my story structure

For my part, I got a chance to try out part of my story structure for the documentary on an audience, hear questions and find out what parts of the narration were of the most interest by their level of attention. There’s just nothing better than trying out your material on a real audience. I’m very pleased with the results but I will continue to refine and expand.

Since I did attend a couple of sessions other than my own, I also had a chance to engage with additional teachers and all seemed very interested in what I’m trying to do. It was only one of the other presenters who gave me pause when he suggested that the next generation would take care of metric conversion in the United States. (Only other time I’ve heard that before [good idea but not now] was in John Quincy Adams’ report to Congress back in 1821—haunts us every time we get serious about metric adoption by the way…) I quickly realized that there was no point in arguing the issue with him but would have loved to point out that in the 30 years since the U.S. Metric Board was disbanded no “next  generation” has come along so far and perhaps he’s part of the “next generation” that should do something. Ah well, I tried to be as persuasive as possible under the circumstances.

As should always be the case, the teacher and learner roles got reversed during my session and I walked away with some additional things to think about and research.

For instance:

• I’ve been told the military uniformly uses the metric system but others have told me that’s not true. True status will take some digging.
• When converting from miles to kilometers, what happens to the mile markers since they’re currently used to help drivers know how many miles to their next exit?
• What’s the best way to convert existing recipes into metric?

The cost of conversion

Of course, the biggest unanswerable question I get asked is how much would it cost to convert to the metric system in this country. I don’t think anyone has a good grasp on that since it’s been so long since the question was seriously considered.

Aside from the cost of conversion errors, and time savings in schools and elsewhere on an individual basis, imagine how much time it takes to design things for multiple countries with dual labeling—including the use of more ink to print both sets.

Converting to the metric system will have a mostly one-time cost while failure to convert to the metric system continues to cost us, and cost us and cost us…

Linda

Someone’s in the Kitchen with the Metric System

I’ve written before about what it would take for us to integrate the metric system into our daily lives but one of the areas where it would really need to take hold is in the kitchen and grocery store. This week I’m addressing the kitchen issue.

What would need to change in YOUR American kitchen

Once the switchover occurs, you’ll be able to hold on to your liquid measuring cups (unless they’re so old they don’t have metric units on them—that would make them pretty old—time for measuring cups 2.0 me thinks.).

A sleek way to move toward metric kitchen measurement.

But you will have to give up your “dry” measuring cups (Hopefully you haven’t been using them interchangeably over the years as I once did.)

Why? Because the metric system measures mass not weight. (Be careful you don’t confuse the two. They’re not the same thing. An object’s weight can change since it’s dependent on gravity but an object’s mass doesn’t change no matter what planet it might be on. Here’s an accessible site in case you want to learn more.)

Using mass instead of volume should improve your cooking, and your baking in particular, since baking tends to be a bit more persnickety when it comes to measurements.

In fact, the King Arthur Flour website goes into quite a bit of detail about the implications of measures and includes:

Although in 1959 English-speaking scientists agreed to use the metric system for scientific and technological purposes, that’s been of little use to bakers.

Needless to say, I hope that will change (Not the right year by a long shot but at least they’ve put the two thoughts together…).

Still, I was surprised that that the company included information that apparently in this country our measuring cups can legally vary by up to 12%!   Add to that that how hard one scoops into a container of flour can also vary how much it holds—by quite a bit.

There can be a variance in how much of a dry ingredient, such as flour, is actually in a measuring device. This is affected by the manner in which it is added to the measuring cup and by how much the ingredient is compacted. Humidity is also a factor in the weight of the dry ingredient. (Recipietips.com)

Talk about a recipe for disaster!

Archimedes scale. Cool but you’d need access to water and has no tare function.

Once we transition, we’re all going to need kitchen scales. I highly recommend a digital version for a couple of reasons: most have a “tare” functions and most can switch back and forth between grams and U.S. Customary units (could be helpful until all our cookbooks are in metric units).

The tare function is really handy because let’s say you want to measure several dry ingredients measured in grams.

First, put your container on the scale and hit the tare button. The number will zero-out so you don’t have to subtract its mass before adding anything else.

Then, let’s say you need 2 grams of salt, 40 grams of butter and 13 grams of baking powder.

You could add the two grams of salt, and then add the butter until you reached 42 grams and baking soda until you reached 53 grams.

Or, much easier, just zero-out the scale with the tare button after each ingredient and put in the exact amounts specified in the recipe.

A truly logical system

One thing that struck me while I was doing research at the Library of Congress a few months ago was the consistency of some of the ingredients in both “weight” and volume measures. Upon reflection, however, it makes perfect sense since the kilogram was designed to have equal volume and mass at the same time.

In the early metric system there were several fundamental or base units, the grad or grade for angles, the metre for length, the gram for weight and the litre for capacity. These were derived from each other via the properties of natural objects, mainly water: 1 litre of water weighs 1 kg and measures 1 cubic decimetre (dm³).  

Where recipes might start to “break down” would be for ingredients that would be much or less dense than water. (See the image below.)

From a metric cookbook that included both mass and volume measures. Note the similarities.

There is another caveat here: depending on how precise your scale is, it might have trouble with small amounts of something. I have seen some metric recipes that measure these small amounts in milliliters rather than mass.

Cutting board with built-in scale. (Hopefully doesn’t dull your knives.)

Unless you have serious concerns about your scales I’d advocate for their use. For those folks who just couldn’t stand the idea of measuring ingredients without spoons, we’d want to trade in our current tablespoon, teaspoon, half and quarter teaspoons for metric units, and while you can buy them here, the measures equate to our current measures so they don’t make a lot of sense: .6 mL and 1.2 mL, etc. Much more logical would be: 1 mL, 2 mL, 5 mL etc. (Maybe when we get our act together we can get them in this country.)

Still, I will say that I have a precision scale that measures down to 1mg and when I used the 10 gram calibration weight on both of my kitchen scales (and not expensive ones, mind you), they were both spot on. So now you know.

A spoon and digital scale in one!

It’s not too soon to start playing around with digital scales and the holidays are just around the corner. Add one to your wish list and help bring others along with you! I’ve includes some really cool ones in this post for you to consider.

And here’s a handy idea of what you can do with your old measuring cups once you no longer need them (reduce, reuse, recycle after all). More on this topic later but I’m keeping a previous promise.

One idea of what to do with old measuring cups once we go metric: an organizer!

I’ll have another post in a week, I promise.

Till then, have fun,

Linda

Notes: Scale images from: http://www.crookedbrains.net/2012/04/creative-and-cool-kitchen-scale-designs.html

Top 10 Reasons to Switch to the Metric System Revisited

As I mentioned last week, some recent media coverage on our lack of metric system use by Discovery News and Scientific American has resulted in a lot of traffic to this site. Of particular interest is my post from last September on the Top 10 Reasons the United States Should Use the Metric System (or SI).

I’ve included some of my statistics for illustration.

All the traffic to this blog

Thought it might be a good idea to dust this off and post it up front. I made a couple of tweaks (I’m a writer, I can’t help myself) and have added a pdf to make it easier to pass around if people so choose. I only ask that the information’s source not be removed since down the road I’ll need to fundraise and I’d like to be tied to this work in people’s minds.

My page stats for the past week

I’ll be back next week with fresh content and, since I’m beginning a new phase of this project, with more “behind the scenes” information that I’m hoping you’ll find interesting.

Top 10 Reasons the United States Should Use the Metric System (or SI)

1) It’s the system 95 percent of the world uses
(It’s not standard in the U.S.,  Burma and Liberia)
2) It’s easier to make conversions
(You just move the decimal point right and left)
3) Teaching two measurement systems to children is confusing
4 ) It’s the language of science
5) It’s the language of medicine
6) Conversion errors by the humans using them are inevitable
(We lost a Mars orbiter that way and pharmacy mistakes are common)
7) It’s the language of international commerce
8) Many hobbies and sports use the metric system
9) Its use is necessary for travel outside of the United States
10) So we look less foolish and ignorant to the rest of the world

And a few more for good “measure..”

11) Less clutter since you don’t need liquid and dry measuring cups and teaspoons and
tablespoons (Just a scale and liquid measuring cups)
12)  It’s much easier to conceptualize 1 gram versus 1/28th of an ounce or 1 milliliter
verses 1/29 of a liquid ounce (rounded measures)
13) There are fewer measures to learn. Most people will use meters, liters, and grams
verses more than 10 for liquid and dry U.S. customary measures alone
14) It was designed to be easy to learn and use
(In 1790s Europe the literacy rate was around 60 percent)
15) It makes us a friendlier international tourist destination.

To_10_Reasons_Metric (pdf)