Chapter 6 Using the metric system of measure.
At the completion of this chapter, the student should be able to:
1. Recite the basic measure of the metric system.
2. Compute length using meters.
3. Compute mass or weight using kilograms or grams.
4. Compute volume using liters.
5. Compute temperature using degrees Celsius.
6. Recognize the increase in the use of metrics in the U.S. food service industry.
7. Change measurements from the customary system to the metric system.
8. Find the cost of food and beverage products using the metric system.
liters or cubic meters
HISTORY OF THE METRIC SYSTEM IN THE UNITED STATES
What is the metric system?
The metric system of measure is a decimal system based on the number 10. It is difficult to understand why this system of measure has never been adopted for exclusive use m the United States. This system is more accurate than the system that is used in the United States, which relies on quarts, pounds, ounces, and so forth. It is especially useful in baking, because baking is a science where exact measurements are needed to produce consistent quality baked products.
France introduced the metric system to the world during the French Revolution. France's lawmakers, during that period of history, asked their scientists to develop a system of measurement based on science rather than custom. They developed a system of measurement that was based upon a length called the meter.
The meter has been used in a limited capacity over the last 30 years, but never to its fullest extent. Perhaps it can be blamed on the fact that most people resist change. There have been attempts over the years to bring about the change. In 1971, the Department of Commerce recommended that the United States adopt the system in a report made to Congress. The report stated that the question was not whether the United States should go metric, but how the switch should take place. It proposed that the switch be made over a 10-year period, as done in Great Britain and Canada. A key element in the Great Britain and Canadian conversion was education. It became the only system taught in the primary schools. The general public was taught the metric system and language by means of magazines, posters, television, newspapers, radio, and so forth. A demonstration center was even set up so that the public could practice purchasing food using the metric system. In the United States, little action was taken on this report until December 23, 1975. At that time, President Ford signed into law the Metric Conversion Act, establishing a national policy in support of the metric system and supposedly ending the dilemma that had continued for so long.
With the signing of the new law it was understood that, through a national policy of coordinating the increasing use of metrics in the United States, the conversion to the metric system would be done on a voluntary basis. The government also created a metric board, appointed by the president with the advice and consent of the Senate. The board was made up of individuals from the various economic sectors that would be influenced most by the metric changeover. Included were people representing labor, science, consumers, manufacturing, construction, and so forth. The function of this board was to create and carry out a program that would allow the development of a sensible plan for a voluntary changeover. This all took place in the 1970s. Today, little is heard of this law or program, although slowly some progress is being made. In 1988, President Bush ordered every federal agency to go metric. However, again the president was not specific as to when the change should occur. No timetable was set--the president left it to each individual federal agency. Some of these agencies have set a date for the change, while others have not. The Federal Highway Administration, for example, moved forward and ordered states to use the metric system in designing all roads that were built after September 30, 1996. If states did not comply, a penalty was assessed.
INDUSTRIES THAT USE THE METRIC SYSTEM
Some industries, notably science, pharmaceutical, engineering, and automotive, have found it necessary to go metric in order to participate in world trade. The medical field has also joined in the use of metric language. Doctors learn early in their training to specify drug dosage in metric units.
Today, over 90 percent of the world's population uses the metric system. It is also used by over nine-tenths of the world's nations.
In the United States, metric measurements are gradually being introduced and used in many industries, among them the food and beverage industry. For example, when a person buys a beverage (soda, coffee, etc.), the measurement often appears on the package in both metrics and the customary measurements that have always been used. For instance, the authors purchased a "to go" cup of coffee, and on the paper cup was printed "12 ounces," along with the metric measurement of "355 ml" (which stands for milliliters). When we received a package of potato chips with our sandwich, the package listed the weight as 1 oz. or 28 g (which stands for grams). Because the metric system is exact, it is better to use this system in baking since ingredients are usually weighed rather than measured. The textbook Professional Baking, 4th edition by Wayne Gisslen has all the recipes in customary (or, as he states, the 'U.S.') measurements, along with metric measurements.
Therefore, as the United States changes to the metric system, the people who will be affected most are those whose jobs are concerned with weights and measures. This is certainly the case for food service workers. Instead of pints, quarts, and gallons, they will have to adjust to liters. Instead of pounds and ounces, they will use kilograms and grams; and instead of degrees Fahrenheit, temperature will be in degrees Celsius (previously known as Centigrade). The purpose of this chapter, therefore, is to make these terms and others dealing with the metric system more familiar to the food service student.
DISCUSSION QUESTION 6-A
Find five food or beverage products that you have at home that have their contents listed in metric measurements. Why are companies listing their contents in metrics?
In recent years, food service students in the United States have been exchanged with students from foreign countries in similar programs. When an exchange like this takes place, certainly recipes and formulas are exchanged, making knowledge of the metric system an asset. The student should be able to convert recipes and formulas both ways, that is, from customary to metric and vice versa.
The metric system is a decimal system based on the number 10. For example, when the meter is divided by 10, it produces 10 decimeters; a decimeter divided by 10 produces 10 centimeters; and a centimeter divided by 10 produces 10 millimeters. To put it another way, one meter equals 1000 millimeters, or 100 centimeters, or 10 decimeters. (Note: the comma is not used in metric notation; instead, a space is left. Example: 1000 millimeters.) This system of measure seems more practical when compared to our customary units of measure-the yard, which is divided into 3 feet (or 36 inches); and the foot, which is divided into 12 inches.
The metric system also provides standard rules for amounts of its units through prefixes. For example, a milligram is one-thousandth of a gram (weight), a milliliter is one-thousandth of a liter (volume), and a millimeter is one-thousandth of a meter (length). When the unit is increased and the prefix kilo is added, a kilogram is 1000 grams and a kilometeris 1000 meters. The customary system lacks this kind of uniformity.
Breaking Down the Metric System
TIPS ... To Insure Perfect Solutions Meters (m) measure lengths; liters (I) measure volume; grams (g) measure weight; and temperature is measured in Celsius ([degrees]C).
UNITS OF MEASURE IN THE METRIC SYSTEM
The best way to learn the metric system is to forget all about the customary measurements and simply think metric. To think metric is to think in terms of 10 and to understand the following basics: the meter represents length; grams, or, inmost cases, kilograms, represent mass; liters or cubic meters represent volume; and degrees Celsius deals with temperature. To compare these new units of measure with familiar ones, a meter is about 39 inches, which is slightly longer than the yard. The gram is such a small unit of mass, approximately 0.035 of an ounce, that to make a comparison it is necessary to take 1,000 grams or 1 kilogram, which is equal to 2.2 pounds. The liter is equal to about 1.0567 quarts, which means it is about 5 percent larger than a quart. There are other units of measure in the metric system, but the ones mentioned are those that will be of most concern to the people involved in food service.
It was stated that to think metric is to think in terms of 10. To show how this is done, take the base unit of length (the meter), and multiply or divide it by 10. Each time the meter is multiplied or divided by 10, special names are attached on the front of the word to indicate the value. These names are called prefixes. Lengths smaller than a meter are divided by 10, and the result is called a decimeter. Dividing a decimeter by 10 gives a centimeter. When the centimeter is divided by 10, it is called a millimeter.
1 decimeter = 0.1 meter
1 centimeter = 0.01 meter
1 millimeter = 0.001 meter
TIPS ... To Insure Perfect Solutions The length of a meter is about one giant step.
So for the units smaller than a meter, the prefixes are deci (a tenth of a meter), centi (a hundredth of a meter), and milli (a thousandth of a meter).
For lengths larger than a meter, multiply by 10. For 10 meters, the prefix deka is used. For 100 meters, the prefix is hecto. The prefix for 1,000 is kilo. So, 10 meters are called a dekameter, 100 meters a hectometer, and 1000 meters a kilometer. Kilo is a very popular prefix because most distances on roadways are given in kilometers.
1 kilometer = 1000 meters
1 hectometer = 100 meters
1 dekameter = 10 meters
VOLUME AND CAPACITY
When measuring volume and capacity, it is first necessary to understand what a cubic meter is before learning what a liter represents. A cubic meter is a cube with the sides each one meter long. In other words, a cubic meter equals the length of one meter, the width of one meter, and the height of one meter. If a metal container is 1/10 of a meter (one decimeter) on each side, it is referred to as one liter. It would contain one liter of liquid and the liquid would weigh one kilogram. When measuring liquid by the American customary system, it is said that "A pint is the pound the world around." In the metric system, it can be changed to "A liter is a kilogram the world around," meaning that every liter of liquid weighs one kilogram, or 2.2 pounds. For units smaller than a liter, a container that has sides one centimeter long is called a cubic centimeter. It would hold one milliliter of water, and one milliliter weighs one gram. From this, of course, it can be seen that, in the metric system, there is a very direct relationship among length, volume, and mass.
MASS OR WEIGHT
The base unit for mass is the gram, but (as stated before) the gram is such a small unit of weight that it did not prove practical for application, so the kilogram (1000 grams) is used as the base unit. It is the only base unit that contains a prefix. When the metric system is adopted, all weights will be given in grams or kilograms. Since the kilogram is a fairly large unit, it may be too large to be a convenient unit for packing most foodstuffs, so the half-kilo (500 grams) may become a more familiar unit. Prefixes such as deci, centi, milli, hecto, and deka may be used with the gram, but they are not practical in everyday life, so the gram and kilogram are the common terms used.
When using the metric system, it has proven difficult to remember the names of all the units and terms, so abbreviations are used. (See Figure 6-1.)
TIPS ... To Insure Perfect Solutions One gram is about the weight of a paper clip. One kilogram is about the weight of a large book or dictionary.
In the metric system, temperature is measured in degrees Celsius ([degrees]C). On the Celsius scale, the boiling point of water is 100[degrees] and the freezing point is 0[degrees]. On the Fahrenheit (F) scale, the boiling point is 212[degrees] and the freezing point is 32[degrees]. (See Figure b-2.) Actually, the official metric temperature scale is the Kelvin scale, which has its zero point at absolute zero. Absolute zero is the coldest possible temperature in the universe. The Kelvin scale is used often by scientists and very seldom, if ever, in everyday life.
To convert Fahrenheit temperature to degrees Celsius: Subtract 32 from the given Fahrenheit temperature and multiply the result by 5/9.
Your restaurant calls for cooking hamburgers to 155[degrees]F. What is the temperature in degrees Celsius?
To convert Celsius degrees to Fahrenheit: Multiply the Celsius temperature by s and add 32 to the result.
Step 1: Subtract 32 from the given Fahrenheit 155 - 32 = 123 temperature. Step 2: Multiply the result by 5/9 123 x 5/9 = 615/9 Step 3: Divide by 9 615/9 = 68.33 Step 4: The answer is 68.33[degrees]C To convert Celsius degrees to Fahrenheit: Multiply the Celsius temperature by 9/5 and add 32 to the result.
[FIGURE 6-2 OMITTED]
Your new job is in a country that gives the temperature in Celsius degrees. What is the Fahrenheit temperature when it is reported to be 25[degrees]C?
Step 1: Multiply the Celsius temperature by 9/5 25 x 9/5 = 45 Step 2: Add 32 to the results 45 + 32 = 77 The answer: 25[degrees]C is 77[degrees]F 77[degrees]F
SUMMARY REVIEW 6-1
Convert the following Fahrenheit temperatures to Celsius. Round off all answers to two places to the right of the decimal point.
1. 23 --
2. 41 --
3. 45 --
4. 140 --
5. 32 --
6. 200 --
7. 450 --
8. 350 --
9. 325 --
10. -10 --
Convert the following Celsius temperatures to Fahrenheit. Round off all answers to two places to the right of the decimal point.
11. 10 --
12. 3 --
13. 27 --
14. 56 --
15. 16 --
16. 75 --
17. 43 --
18. 12 --
19. 18 --
20. 4 --
Converting Recipes from Customary Measurements to the Metric System
A tremendous amount of recipes have been written since this country was founded. Almost all of these recipes are written in customary measurements. Some of these recipes are family favorites that the culinarian would like to duplicate in the food service occupation in which he or she works. To assist in helping the U.S. cooks learn about both the customary and metric systems, companies like Ohaus are developing and selling scales that weigh by the pound, decimal ounce, fractional ounce, gram, and kilogram.
Figure 6-3 is a chart that provides the multiplier to the culinarian in order to convert customary measurements to metric units.
Using the information from Figure b-3, we will illustrate how to convert a fricassee of veal recipe, as shown in Figure 6-4.
The first ingredient (18 pounds of veal) is multiplied by the kilogram multiplier of 0.4535 925, found in the Mass or Weight section in Figure 6-3. The result is 8.164665 kilograms. The last item, flour, is converted to ounces and multiplied by the grams multiplier. When Figure 6-3 is consulted, notice that we are multiplying like amounts; for instance, we multiply pounds by the multiplier for kilograms, we do not multiply pounds by the multiplier for grams. It is necessary to change items into correct categories-otherwise, the answer will be wrong. Follow this same procedure to convert a recipe from the metric system to the customary system, as shown in Figure 6-6.
Figure 6-5 is a table for converting metric measurements to customary measure.
Figure 6-6 illustrates how to convert an eclair dough recipe from metric to customary measurements. This also demonstrates why metric measurements are more exact. When converting the butter, the metric measurement is exact at 450 g, but to weigh out 15.87 oz. will be difficult, so the baker adds a pound of butter.
Figure 6-7 provides equivalents of weights and measures between the customary and metric measurements that may be used as a quick reference, and may prove helpful to the food service professional.
SUMMARY REVIEW 6-2
1. Convert recipes (a) through (e) from the American customary system to the metric system. Use the conversion table shown in Figure b-3. (a) White cream icing ingredients 1 lb. 4 oz. shortening -- g 1/4 oz. salt -- g 5 oz. dry milk -- g 14 oz. water -- ml 5 lb. powdered sugar -- kg vanilla to taste -- to taste (b) Yellow cake ingredients 2 lb. 8 oz. cake flour -- kg 1 lb. 6 oz. shortening -- g 3 lb. 2 oz. granulated sugar -- kg 1 oz. salt -- g 1 3/4 oz. baking powder -- g 4 oz. dry milk -- g 1 lb. 4 oz. water -- g 1 lb. 14 oz. whole eggs -- g 12 oz. water -- ml vanilla to taste -- to taste (c) Italian meringue ingredients 1 lb. egg whites -- g 1 lb. 8 oz. water -- ml 1 lb. 12 oz. sugar -- g 12 oz. egg white stabilizer -- ml oz. vanilla -- ml (d) Vanilla pie filling ingredients 12 lb. liquid milk -- kg 4 lb. granulated sugar -- kg 1 lb. cornstarch -- g 4 oz. salt -- g 2 lb. whole eggs -- g 6 oz. butter -- g vanilla to taste -- to taste (e) Fruit glaze ingredients 2 lb. water -- g 2 lb. 8 oz. granulated sugar -- kg 8 oz. water -- ml 4 oz. modified starch -- g 4 oz. corn syrup -- ml 1 oz. lemon juice -- ml food color as desired 2. Convert recipes (a) through (e) from the metric system to the American customary system. Use the conversion table shown in Figure 6-5. Answer should be carried out three places to the right of the decimal point. (a) Chicken a la king ingredients 4.5 kilograms boiled chicken or turkey, diced -- lb. 0.45 kilograms green peppers, diced -- lb. 227 grams pimentos, diced -- oz. 0.9 kilograms mushrooms, diced -- lb. 2.8 liters chicken stock -- qt. 0.74 kilograms flour -- lb. 0.9 kilograms shortening -- lb. 2.8 liters milk -- qt. 240 milliliters sherry wine -- fl. oz. (b) Tartar sauce ingredients 110 grams dill pickles, chopped fine -- oz. 60 grams onions, chopped fine -- oz. 0.14 grams parsley, chopped fine -- oz. 1 liter mayonnaise -- qt. 5 milliliters lemon juice -- tsp. (c) Cocktail sauce ingredients 0.95 liters catsup -- qt. 0.6 liters chili sauce -- oz. 0.24 liters prepared horseradish -- oz. 120 milliliters lemon juice -- oz. 34 milliliters Worcestershire sauce -- oz. hot sauce to taste -- to taste (d) Spicy peach mold ingredients 0.95 liters peaches, canned, sliced, drained -- qt. 0.45 liters peach syrup -- oz. 0.45 liters hot water -- oz. 0.95 liters cold water -- oz. 0.24 liters vinegar -- oz. 0.36 liters sugar -- C. 28 grams cinnamon stick -- oz. 15 milliliters whole cloves -- tsp. 392 grams orange gelatin -- oz. (e) Brussels sprouts and sour cream ingredients 2.7 kilograms brussels sprouts -- lb. 30 milliliters salt -- tsp. 112 grams onions, minced -- oz. 144 grams butter -- oz. 0.90 kilograms sour cream -- oz. water to cover, boiling "The knowledge of mathematics is so important in baking because it insures the result is the same with each formula produced, regardless of its amount or volume. Scaling and measuring accurately are absolutely imperative. The United States is the only major country that uses a complex system of measurements (pounds, ounces, etc). The rest of the world uses the metric system. Most people think the metric system is harder than it actually is. Metric kitchens do not work with impractical numbers, such as 454 g = 1 lb., 28.35 g = 1 oz., or 191[degrees]C. No surprise, most people are scared of the metric system. American industry will probably adopt the metric system sometime in the future."
Chef Richard Wagner is the executive pastry chef at the Oahu Country Club in Honolulu, Hawaii. This exclusive, premier diamond country club is the oldest private club west of the Rockies; it was founded on June 8, 1906. Chef Wagner has had a vast amount of experience as a pastry chef on cruise ships and in first-class hotels and pastry shops, both domestic and international. Chef Wagner is also a chef/instructor/lecturer at the Kapiolani Community College at the Diamond Head Campus in Honolulu. Chef Wagner was awarded a master's degree in patisserie and confiserie from the Culinary Institute of Vienna in 1972.
Figure 6-1 Metric units and their symbols Quantity Unit Symbol Length meter m decimeter dm centimeter cm millimeter mm kilometer km hectometer hm decameter dam Volume cubic centimeter [cm.sup.3] cubic meter [m.sup.3] Capacity milliliter ml liter l Mass gram g kilogram kg Temperature degrees Celsius [degrees]C Figure 6-3 Conversion from customary to metric units When you Multiply know by To find Symbol Length Inches 2.54 Centimeters cm Feet 0.3048 Centimeters cm Yards 0.9144 Meters m Miles 1.609347 Kilometers km Capacity Teaspoons 5 Milliliters ml Tablespoons 15 Milliliters ml Fluid Ounces 29.574 Milliliters ml Ounces 0.031 Liters 1 Cups 0.241 Liters 1 Pints 0.04732 Liters 1 Quarts 0.951 Liters 1 Gallons 37853 Liters 1 Mass or Ounces 28.35 Grams g Weight Pounds 0.4535925 Kilograms kg Figure 6-4 Converting a recipe from customary measurements to metric measurements How to convert the recipe Multiply Ingredients by Metric 18 pounds of veal shoulder cut into 1-inch cubes To solve the problem: multiply 18 times (x) 0.4535925 = 8.164665 kilograms 3 gallons of water 3.7853 = 11.3559 liters 2 pounds of shortening 0.4535925 = 0.907185 kilograms 1 pound 8 ounces of flour (change this to ounces) 1 pound = 16 ounces + 8 = 24 ounces To solve the problem: multiply 24 times (x) 28.35 = 680.4 grams Salt and pepper to taste Figure 6-5 Conversion from metric measurements to customary measurements When you Multiply know by To find Symbol Length Millimeters 0.04 Inches in. Centimeters 0.39 Inches in. Meters 3.28 Feet ft. Meters 1.09 Yards yd. Kilometers 0.62 Miles mi. Capacity Milliliters 0.2 Teaspoons tsp. Milliliters 0.07 Tablespoons tbsp. Milliliters 0.03 Fluid ounces fl. oz. Liters 30 Ounces oz. Liters 4.23 Cups C. Liters 2.11 Pints pt. Liters 1.06 Quarts qt. Liters 0.026412 Gallons gal. Mass or Grams 0.03527 Ounces oz. Weight Kilograms 2.2046 Pounds lb. Figure 6-6 Recipe conversion from metric to customary measurements Multiply Ingredients in metric by Customary 500 ml water To solve the problem: multiply 500 times (x) 0.03 = 15 fl. oz. 5 ml salt 0.2 = 1 tsp. 22 ml sugar 0.07 = 1.54 or 1 1/2 tbsp. 450 g butter or margarine 0.03527 = 15.87 oz. or 1 1b. (16 oz.) 450 g bread flour 0.03527 = 15.87 oz. or 1 lb. (16 oz.) 16 eggs 16 eggs Figure 6-7 Weights and measures equivalents Metric Customary 1 gram = 0.03527 ounce 1 kilogram = 2.2 pounds 28.35 grams = 1 ounce 4535925 grams = 1 pound 5 milliliters = 1 teaspoon 15 milliliters = 1 tablespoon 241 milliliters = 1 cup 0.4732 liters = 1 pint 0.951 liters = 1 quart 1 liter = 1.06 quarts
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|Title Annotation:||PART III Math Essentials in Food Preparation|
|Publication:||Math Principles for Food Service Occupations|
|Date:||Jan 1, 2007|
|Previous Article:||Chapter 5 Weights and measures.|
|Next Article:||Chapter 7 Portion control.|