Extension Bulletin 691
LYNN PRICE,
Extension Foods Specialist
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AT HOME IN THE KITCHEN
WITH METRICS
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Your work in the kitchen will change somewhat when we convert to the metric system. During food preparation and selection, you will be
using each of the four basic metric units:
gram for weight of purchased ingredients
liter for volume of measured and purchased ingredients
meter for length and width of equipment, plastic wraps, and some food ingredients
degrees Celsius for temperature of oven, refrigerator, and food
Four prefixes which make the basic units
smaller or larger will also be important to food
preparation and selection: kilo ( 1000 X) , deci
(1/ 10) , centi (1/ 100), and milli (1 / 1000).
The WSU Cooperative Extension publication,
"The Metric System," offers more detailed explanations of the use of these prefixes in combination with the basic units.
METRICS IN THE SUPERMARKET
One of the first places you will notice use of
the metric system is in the supermarket. And you
can already find metrics there!
Packaged and Canned Foods
and Paper Products
Many packaged and canned goods are labeled
with both customary and metric units. This is
called dual labeling. The most common metric
unit currently used is the gram. Weight of the
contents of a can of green beans might be given
as :
NET WT. 16 oz. (1 lb.)
454 grams
Eventually, manufacturers of food products
will probably change the size of their containers
so that food products can be sold in more even
metric numbers; for example, rather than purchasing a 1 pound ( 4 54 gram) can of green
beans, you will be able to purchase a 5 00 gram
can.
You can also find foods sold by volume which
. are dual labeled in ounces, pints, or quarts and
milliliters or liters. A soft drink manufacturer is
already marketing 1 liter ( 33.8 oz.) drinks.
Metric units for weight and for volume will
be much easier to use than our customary measures. The reason for this is that there are several
customary units which express weight (ounce
and pound) and volume (fluid ounce, pint, quart,
and gallon). Notice that both weight and volume
can be measured in ounces. Thirty-two fluid ounces
equal one quart while 16 ounces equal one pound.
This type of confusion should not occur with
metric units for weight and volume since there
is only one basic unit for each, the gram and the
liter.
Few food-related items sold by length are
presently dual labeled. Soon, we should see wax
paper, paper towels, etc. sold by square feet,
feet, or yards, and square meters or meters.
Packaging laws for the metric system have not
yet been completed, but it is hoped that when
manufacturers resize to metric sizes, they will
standardize and use a few common sizes (for example, 250 milliliters, 500 milliliters, 1 liter, and
2 liters) rather than continue the diversity of sizes
on the market today. This will help consumers
adapt to the new sizes more quickly, and it should
make cost comparisons easier.
Just having one unit per package should also
help the consumer. With our customary system,
COOPERATIVE EXTENSION SERVICE • COLLEGE OF AGRICULTURE • WASHINGTON STATE UNIVERSITY • PULLMAN
it is possible to find packages labeled: NET
WEIGHT 2 lbs. 10 oz. Metrically, this net weight
will appear in either grams or kilo grams-not
two -different units. Packages labeled "2 feet 4
inches wide" will appear metrically only in centimeters.
Take a look through your cabinets. Pull out
cans and packages which are dual labeled. You
will be surprised at the number. Feel the weight
of each and note the number of grams. Look at
the volume of jars and compare that volume to
the number of milliliters indicated on the label.
Metric packaging guidelines of the Federal
Trade Commission recommend that units describing package contents be used so that numerical
values are between 1 and 1000; for example, use
1.96 kg instead of 1960 g or use 750 mm instead
of 0.75 m. The FTC guidelines indicate that decimals such as 0.25 and 0.5 should be used to indicate portions of a unit. Fractions such as Y4
and Y2 are not permitted.
Nutritional Labeling
Look on the back or side panels of canned
and packaged goods. Nutritional labeling is required on labels of all foods which make a nutritional claim. Some manufacturers are voluntarily adding nutritional labeling to other foods as
well. Look on the example below at the metric
units which already appear.
Example of Dual Weight and Nutritional Labeling
NET WT. 12 OZ. (340 GRAMS)
NUTRITION INFORMATION
Serving Size ... 1 cup
Per One-Cup serving:
30 grams
Calories .... ... .. ....... 150 Carbohydrates
Protein ...................... 4 grams Fat
..............1 gram
PERCENTAGE OF U.S. RECOMMENDED
DAILY ALLOWANCE (U.S. RDA)
Protein
......................... 6 Riboflavin ...... ...... .. ....... 6
Vitamin A
...... 4
Niacin .
................ 6
Vitamin C
............... 25 Calcium
.... 0
Thiamine ............................... .... 2 Iron
......... .......... ... .. 4
The weight of each major nutrient contained
in the food is expressed in grams. The weight of
a nutrient is usually so small that it would have
to be expressed in customary units as some fraction of an ounce. Keep in mind that a gram is
approximately the weight of a paper clip.
As metric takes over, the term calorie will be
replaced with kilojoule. There are about 4.2 kilo-
joules in one calorie. Just think, a 2200-calorie
diet today will be a 9340-kilojoule diet tomorrow!
Fresh Foods
We will also buy fresh foods by metric measures. Meat and fresh fruits and vegetables will be
sold by either grams or kilo grams. This will not
be so different from the customary system since
the weight of most prepackaged meats and produce is already expressed in decimals; for example,
a roast weighs 3.7 5 pounds, not 3 pounds 12
ounces. Metrically, this same weight would still
be expressed in a decimal quantity, 1.7 kilograms.
Milk will be sold by the liter. For a while,
cartons will be labeled 1 quart ( 95 0 milliliters) .
Manufacturers will someday change carton dimensions (probably height) so that cartons can
accommodate a full liter ( 1.06 quarts) .
Overall Buying Habits
Will the metric system really change your
buying habits? Probably not, because you already
select many of your foods by how big they look;
"This roast looks large enough to serve my family"
or "I need to purchase a can of soup, a small package of noodles, a large loaf of bread, and a head
of lettuce."
Besides appearance, many items are bought
by count instead of weight or volume. When we
change to metrics, a dozen eggs will still be a
dozen eggs, and five bananas, still five bananas.
Metric Food Prices
Grocery advertisements and food prices may
appear different at first. Lean ground beef advertised for $2.50/ kilogram may seem expensive
until you realize that a kilogram of lean ground
beef will make at least nine large hamburgers!
A 500 gram can of green beans should cost about
10 per cent more than a 1 pound ( 454 ,gram)
can because it actually contains 10 per cent more.
Most foods sold metrically will be slightly more
expensive than their customary counterparts because, in nearly every case, the metric unit is larger.
Once you become familiar with prices per
metric unit, you can compare unit prices one to
another just as you do now. You may soon be
saying: "Pork steaks are up 10¢/ kilogram over
last month."
MEASURING METRICALLY AT HOME
Have you purchased a glass measuring cup
lately? If so, it is probably labeled in fluid ounces
and fractions of cups as well as in milliliters.
Measuring spoons can be purchased which are
marked in teaspoons and tablespoons as. well as in
milliliters.
Once we begin using the metric system completely, we will probably discard the terms "~­
cup," "V3-cup," etc. and begin seeing all measurements of volume in milliliters (mL). A special
committee of the American Home Economics
Association working with the American National
Standards Institute has recommended that manufacturers make available three sizes of glass measures for liquids, three sizes of measures for dry
ingredients, and five sizes of spoons for small
quantities.
Recommended Measuring Devices for
Home Food Preparation
long and to broil 4 centimeter steaks 10 centimeters below the heating element of the oven!
To help you visualize this, think of 1 centimeter
being equal to the width of the tip of your little
finger.
Temperatures will be measured in degrees
Celsius. Rare beef should be heated to 60 °C; refrigerators should be kept at about 3 o C; and
asparagus will be pressure canned at 116 o C.
Some meat, candy, refrigerator/ freezer, and oven
thermometers are presently available in both
Fahrenheit and Celsius scales. Stick-on decals for
some oven controls or new control knobs can be
purchased to show both Fahrenheit and Celsius.
Be sure and purchase these from the manufacturer
of your range. Or look at the following table and
mark Celsius temperatures on your range to correspond to the Fahrenheit ones already there:
Oven Temperatures in Celsius and Fahrenheit
liquids
cup
dry
cup
ingredients
small
spoon
quantities
250 mL 25 mL
500 mL 50 mL
1000 mL 50 mL
50mL
125 mL
250mL
1 mL
2 mL
5mL
15mL
25mL
1 cup
2 cups
4 cups
Y4 cup
Y2 cup
1 cup
Y4 teaspoon
Y2 teaspoon
1 teaspoon
1 tablespoon
2 tablespoons
You can measure 7 5 milliliters milk in a 2 50
milliliter measure since every 25 milliliters will
be marked on the new cup, just as every ~ cup
is marked on a customary measuring cup. If your
tnetric muffin recipe calls for 7 mL baking powder, obtain it with a 5 mL and a 2 mL measure.
If your fruitcake recipe calls for 175 mL sugar,
use a 50 mL and a 125 mL dry measure. Metric
measures are used in combination just as customary measures are. In customary measuring, we
would use ~ cup and Y2 cup to measure % cup
flour.
It has been recommended that the new 2 50
mL cup be called the "metric cup."
While measuring length metrically, you might
be instructed to cut celery sticks 15 centimeters
slow
moderate
hot
very hot
Celsius
degrees
Fahrenheit
degrees
121-163
163-190
190-218
218-260
250-325
325-375
375-425
425-500
Eventually, we will use rounded Celsius numbers ( 125 °C rather than the 121 °C above).
The change to the metric system will make
little difference in surface cooking. You can melt
butter without knowing the temperature at which
you do it. You can "see" food simmering or boiling-no matter which temperature scale you use.
Pots and pans will soon be purchased by
lengths and widths or diameters measured in centimeters. Although some recipes require that a certain size pan to be used, you normally just select
a cookie sheet large enough to hold 12 biscuits, a large-enough skillet in which to stir-fry
your cabbage, or a saucepan which is the right size
to hold your vegetable soup.
Manufacturers will soon begin to dual label
the capacity of casseroles and saucepans; for example, 1 quart ( 0.95 liter) . When producers decide to produce a new casserole style or when they
must retool, they will probably increase the volume of the casserole so that it is labeled 1 liter
( 1.06 quarts) .
METRIC RECIPES
Experienced cooks seldom use many recipes.
You pour a little of this, shake in some of that,
etc., then taste to see if it is "good." If it is not
exactly right, you might add something else.
Whether you are cooking conventionally or metrically, you will still add and taste.
Most cooks do use recipes for baked products
to obtain consistent results. Recipes are .also used
to try new foods. Metrication will not mean throwing away treasured recip~s, cookbooks, or utensils.
Staples will soon be purchased in even metric
units, but there is no reason, for a while, that
you cannot use your old customary 1-cup measure to dip sugar from a 2-kilogram bag.
Metric recipes will look different at first. Volume of ingredients will be given in milliliters;
sizes of pans, in centimeters or liters; and oven
temperatures, in degrees Celsius.
The 250 milliliter measure will probably be
used by professionals as a basis for developing
recipes-just as our conventional cup was previously used. Our customary cup contains about
237 mL rather than 250 mL; therefore, metric
recipes will probably produce yields slightly larger than similar customary recipes since all other
ingredients must be increased proportionally to
the larger "cup."
You should buy a set of metric measuring
equipment in order to use metric recipes. If you
have both metric recipes and metric utensils, food
preparation using metrics should be as simple as
our customary system is now.
It is not necessary to buy new pans because
their diameters or lengths and widths are given in
inches-not centimeters. Use a metric tape measure or ruler which is marked in centimeters to
measure the pans you already own. If you wish,
mark this quantity on the pots and pans. Determine the capacity of saucepans in liters by filling
them with water, then measuring the quantity of
that water in metric measuring cups.
As new metric recipes appear, they may be
written in metric units only or in both types of
units. The material in the box in the next column
shows an example of the latter type.
It is best not to try to convert conventional
recipes to metric or to try to convert metric recipes
to conventional. Trying to convert recipes may
result in errors so that food products fail.
The easiest approach is to continue to use
your conventional measuring equipment with conventional recipes and to use metric measurmg
equipment with metric recipes.
Sample Recipe for Individual Meat Loaves
in Both Metric and Customary Units
Ingredients
Metric Measure
lean ground beef
tomato sauce
cracker crumbs
chopped onion
egg
salt
pepper
Cheddar aheese
ketchup
1
1
125
75
1
5
1
250
75
kilogram
can
milliliters
milliliters
milliliters
milliliter
grams
milliliters
Customary
Measure
2.2 pounds
1 can
Y2 cup
Y3 cup
1
1 teaspoon
Y4 teaspoon
9 ounces
Y3 cup
Combine meat, tomato sauce, crumbs, onion, egg,
salt, and pepper. Divide into 12 parts and shape each
into a 9 em x 7 em (3Y2 in. x 2% in.) patty. Cut
cheese into 8 em x 1.5 em x 1.5 em ( 3 in. x ¥3 in. x
V3 in.) sticks. Place 1 cheese stick on the top of
each of 6 patties. Top with remaining patties. Press
and shape into individual loaves. Place loaves on a
rack in a roaSiting pan. Bake in a 17 5 °C oven
( 350 °F.) for 30 minutes. Top cooked loaves with
ketchup. Continue baking 15 to 20 minutes.
If you feel you must convert, a conversion card
has been produced by the U.S. Department of
Commerce, and charts with some conversion factors can be found in "The Metric System," WSU
Extension Bulletin 690.
MEASUREMENTS BY WEIGHT
Some countries now using the metric system
measure their dry and solid ingredients by weight
rather than by volume; for example, a recipe for
muffins might call for 230 grams flour rather
than 500 mL sifted flour. By weighing the flour,
the sifting step is eliminated so the sifter, wax
paper, various size measuring cups, and straightedge spatula are not needed.
More consistent measurements are obtained by
weighing. Measuring by volume leads to inconsistencies because some ingredients pack easily
and others stick to measuring cups. You might
pack more flour into a cup today than you did
yesterday, or you might fail to remove all of the
shortening from a measuring cup.
To make the changeover to metrics as simple
and inexpensive as possible, Americans will not
be required to purchase gram scales and learn the
weighing procedure. You may wish to do so for
.fun, however.
Published and distributed in furtherance of the Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department
of Agriculture, by the Washington State University Cooperative Extension Service, ]. 0. Young, Director. Extension programs are available to all persons without discrimination. Published August 1977, Reprinted December 1978.