Last month’s article was about using thermometers to measure temperature. This month’s 50 Minute Classroom column is about measuring both solids and liquids.
Let’s start with solids. The three most common methods for measuring solid ingredients are by cups, weight, and (for smaller amounts) teaspoons. Many commercial recipes, particularly for baking, give measurements by weight. The main reasons for this are when you deal with large quantities it is difficult to measure cups (imagine measuring 75 cups of flour) and a given weight is always the same. One pound or one kilo is always one pound or one kilo.
The best way to demonstrate this is to give each group of students a standard measuring cup and ask them to bring you a cup of flour. Then, weigh the results and write the measurements on the board. Ideally, each cup should weigh four-and-a-quarter ounces or 120 grams. Your students will be surprised at the wide discrepancy of weights. Then ask each group to share a scale and bring up four-and-a-quarter ounces of flour. Write the results on the board. They should be uniform at four-and-a-quarter ounces.
There are three basic types of kitchen scales: a balance scale where counter weights are used to determine the weight, electronic scales, spring loaded scales. The first, balance scale, is seldom used and the rest of this article will assume your students are using electronic or spring-loaded scales.
Measuring with Scales
Place the scale on a level surface. Put a container on top of it and zero out the scale. This is done by turning a knob on a spring-loaded scale or pushing the zero button on a digital scale. If your students don’t zero it out, then they will not have an accurate measurement. If your students don’t zero out the scale but have already put the product into a container, they might not have to start over. If there is a similar empty container, let’s say a stainless half pan, they can put the empty pan on the scale, zero it out, and then put the pan they started loading back on the scale for measurement.
Measuring with Cups
You need to make sure your students understand there are cups for measuring solids and cups for measuring liquids. Generally speaking, the cups for measuring liquids are clear and have a handle that begins near the top and travels down almost to the cup’s bottom. Cups for measuring solids are usually opaque plastic or metal and the handle is fastened to the top of the measuring cup and is perpendicular to the cup. In other words, you can’t measure a solid like flour in a measuring cup designed for measuring liquids.
In measuring solids, you need a measuring cup with a flat lip where you can move the back of a knife across the top of the measuring cup. If a recipe calls for one cup it means one level cup, one-half cup means one-half level cup, etc. Your students need to be shown how to use a measuring cup designed for solids as a scoop, starting with scooping up the product without packing it down. The product should be bulging over the top of the cup. You then teach them to use the back of a knife to gently sweep across the top of the cup making the product level. Sweeping the back of a knife over the top is why you can’t use a liquid measuring cup for measuring solids, and why you must use the right size measuring cup. If you use a one cup to measure a half-cup of corn meal you can’t sweep the back of the knife across the top.
Measuring with Teaspoons
Students apply the same procedure when measuring with teaspoons. Either scoop up the product (such as baking soda) with some going over the rim, or pour the product (such as salt) so the product is over the rim and then gently level it out with the back of a knife. As with measuring cups, you must use the right size. You can’t measure half-of-a-teaspoon by estimating half of the space in a whole teaspoon.
(Note: Occasionally recipes, often for brown sugar, will say to pack the sugar into the measuring cup. To be candid, this is problematical. You are back to the experiment referred to above of weights ranging depending on who is packing the sugar into the cup.)
Measuring liquids is usually done by volume: gallons, quarts, pints, cups, etc. The larger the production amount, the easier it is to measure. It is a lot easier to measure two gallons of milk than two cups. When measuring liquids with measuring cups you need to make sure your students know what each line represents.
To fill and read a measuring cup your students need to be taught NOT to hold it in their hands. The students need to be shown to put the cup down on a level table and add the liquid until it is level with the correct mark. The curve of liquids at the top is called meniscus. The bottom of the meniscus should be at the measuring line of the cup for the measurement you are seeking. Do not read the top part of the meniscus. Students will either have to squat or bend their heads down to read this. You cannot measure a liquid accurately looking down at the cup.
If you are teaching a class in commercial cooking you will also need to teach your students how to measure by ladles and scoops. Commercial food service ladles, in most instances, have their size stamped on the handle. If not, they can be measured against a liquid measuring cup. What looks like ice cream scoops to your students are called “dishers” in a commercial kitchen. The color of the handle represents the size of the scoop. For a good chart of colors/sizes in metric and ounces have your students print out Wikipedia Scoop (Utensil)--Disher.
One final thought, serving spoons are not standardized, and thus if you are going to use a serving spoon as a constant measure (for example, plating mashed potatoes), then put one serving on the spoon, and then weight the serving. Adjust the amount you are putting on the spoon as appropriate. Then you will know how much food should go on the spoon for each serving.
Your students will argue that on television there are many times where careful measurements aren’t taken. You have two responses: 1) television isn’t real life for much of the time, and 2) there are many experienced cooks and chefs who can estimate volume and weight quite well by look or feel, but these people have extensive experience and practice. I told my students that when they have their own television shows, or acquired more than 10 years of experience, they can disregard accurate measurements.
[Author’s Note: You may wish to look at one of the most popular 50 Minute Classroom articles, "Teaching Thanksgiving Side Dishes in 50 Minutes,” for your November classes.)
Chef Adam Weiner, JD, CFSE, has been a culinary instructor in the San Francisco Bay Area for more than 16 years.