Dear John,
I have interspersed some remarks in red.
On 2009/04/05, at 1:35 AM, John M. Steele wrote:
Pat,
You understandably write from a Commonwealth or Australian
perspective (I don't mean spelling),
True.
and as a metric consultant, you may have a vested interest in making
old measurements sound more confusing than they are.
I have very little need to do this. Old pre-metric measures are
generally more difficult that their metric equivalents without any
help from me.
I am confused by spoons and cups in recipes from Commonwealth nations.
You have every right to be confused. There has never been, to my
knowledge, any international co-ordination of cooking measures. Most
nations simply used soft conversions and rounded them to end with a 5
or a zero. For example, the UK and the USA took the old half ounce
'table spoon' and relabelled it as 15 millilitres; then they took the
old pre-metric 8 ounce cup and relabelled it as 240 millilitres.
To the best of my knowledge only in Australia and New Zealand did
leading cooks choose the metrication process in the 1970s as an
opportunity to completely rethink all kitchen measurements. Here are
some examples of rounding to achieve slight increases of between 6 %
and 10 %:
454 grams was rounded to 500 grams (+ 10 %) from 1 lb.
568 millilitres was rounded to 600 mL (+ 6 %) from 1 pint (Imp.)
28.3 ounces was rounded to 30 mL (+ 6 %) from 1 Imperial ounce.
This method gave Australia cooks the rational methods we use today.
The problem was that, as a multicultural nation, we had many different
sources of traditional recipes from every nation in the world. For
example, when my wife and I volunteered to compile a recipe book for a
retirement village based on the residents recipes, we encountered
these old pre-metric measures: bushels, coffee cups, degrees
Fahrenheit, demitasse, dessertspoons, drams, drops, gallons, gas
Regulo, gills, glasses, grains, hundredweights, Imperial gallons,
noggins, ounces, packets, pecks, pennyweights, pints, pounds,
quarters, quarts, sacks, salt-spoons, scruples, tablespoons, teacups,
teaspoons, tins, U.S. quarts.
These were all component parts of old family recipes that had been
treasured in the donor's family sometimes for generations. One old
lady told us, 'This recipe came to me from my great, great, great,
grandmother.' Had we simply recorded the recipes then bound and
published the book, the treasured old recipes could well be lost to
all future generations because the children of the 21st century who
will inherit this book would find these measures totally
incomprehensible; the book would sit unused on the shelf, and the
recipes would eventually be lost. We had no choice but to write the
recipes in metric units and then test every recipe.
However, if you receive a recipe from the US, there is no confusion;
the terms are well-defined and have been for some time. I regularly
use a recipe from my greatgrandmother which dates to around 1890.
Common cups and spoons may be of any size, but measuring cups and
spoons are well defined. They are as important to us as your scales
(most are marked in metric as well).
But are the definitions exactly the same as in your grandfather's day?
Each term is followed by a definition in Customary units, an overly
exact metric conversion, and a practically rounded metric conversion:
cup: 8 US fl oz, 236.5882 mL, 240 mL
ounce: 1 US fl oz, 29.573 53 mL, 30 mL
Tablespoon: 0.5 US fl oz, 14.786 76 mL, 15 mL
teaspoon: 0.1666... US fl oz, 4.928 922 mL, 5 mL
It's probably not an over exact metric conversion. It looks like it
was converted from an over exact cubic inch. Let me quote from
something you wrote in about mid 2007 (http://www.metricationmatters.com/mm-newsletter-2007-06.html
)
John M Steele wrote to add to the discussion that Bill Hooper and I
had shared over the size of a tablespoon. To remind you, I had
suggested that the tablespoon in the USA was a 'hidden' half-ounce but
Bill Hooper disagreed.
John M Steele noted:
However, in the US all measuring spoons have been marked 1 Tablespoon/
15 mL, and 1 teaspoon/5 mL for some time.
John referred to NIST Handbook 44 where Appendix C provides
definitions of teaspoons and tablespoons on pages C18 and C19. The
NIST Handbook defines the measuring cup as 8 fluid ounces exactly. It
defines the tablespoon as 3 teaspoons exactly, 1/2 fluid ounce
exactly, and 15 milliliters. It defines the teaspoon as 1/3 tablespoon
exactly, and 5 milliliters adding that a teaspoon and a tablespoon are
rounded to the nearest milliliter.
John then added:
5 mL and 15 mL is sufficiently accurate for any rational purpose, but
teaspoon and tablespoon are defined precisely as rational integer
ratios of fluid volume measure. If you pound through the chain of NIST
Handbook definitions, 1 tablespoon = 231/256 cubic inches and 1
teaspoon = 77/256 cubic inches, and 1 cubic inch = (2.54 cm)^3, thus
the exact conversion is more like 14.787 mL and 4.929 mL.
Dry and wet measuring cups are of different designs, but the same
capacity. Dry cups are brim fill, stricken level with the back edge
of a knife. Wet cups are fill-to-mark.
American cooking is entirely volumetric, and it is probably easier
to convert to metric volume than determine the density of
everything. The cup and tablespoon are noticably different than
Australian, but no confusion as the terms are well defined and
standardized by NIST (handbook 44 Appendix, C, SP811, etc)
Again, Australian cooking leaders chose to increase the size of a cup
during the metric transition. An Australian cup is 250 millilitres (up
from 8 ounces or 10 %). This gave Australians the convenient
relationship of having 4 cups to the litre, but it made it a little
more difficult to divide into 1/4 cups and 1/3 cups. At our house, we
cheat. When we are dividing cups, we think of them as holding 240 mL
rather than 250 mL; then 1/4 cup is 60 mL, 1/3 cup is 80 mL, etc.
Now, if only we could get Americans to convert the above volumes to
metric.
If you're looking for a model to copy, I can recommend the Australian
way — because it works.
Cheers,
Pat Naughtin
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that they
now save thousands each year when buying, processing, or selling for
their businesses. Pat provides services and resources for many
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and government metrication leaders in Asia, Europe, and in the USA.
Pat's clients include the Australian Government, Google, NASA, NIST,
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