Hot Ice Cream

First, you will experiment with making hot ice cream. You will try different cooking times and observe how it melts. Once you are familiar with the process and have chosen a specific cooking time, you will test this cooking time on three different hot ice cream solutions, make detailed measurements, and pick your favorite hot ice cream recipe.

Before starting with the experiments, you will need to plan the following:

• Make the recipes a day ahead, as the solutions need to rest in the refrigerator for one complete day (24 hours).
• Take your recipe out the refrigerator one hour before you plan to start cooking. This gives the solutions time to adjust to room temperature.
• You can keep your ice cream solutions for up to three days; however, make sure to perform the detailed measurements on the same day. The solutions will slightly thicken as time passes, which will alter your measurements. If you do take a break, be sure to store your solutions in the refrigerator.

Preparing Your Hot Ice Cream Solutions

Hot ice cream is made by cooking your ice cream solution (which contains methyl cellulose) in the microwave. In this section, you will prepare 3 solutions. All will start from the same base recipe: a mixture of water, milk, cream, sugar and vanilla extract. You will then dissolve different amounts of methyl cellulose into the base recipe to create the different ice cream solutions.

1. Prepare the base recipe.
   1. Gather all your ingredients as shown in Figure 2.
   2. Weigh each ingredient listed in Table 1, one by one. Section How to Use a Scale can help you use your scale accurately.
   3. Pour all ingredients into a microwave-safe mixing bowl.
   4. Mix the solution well with a fork. The result should look like shown in Figure 3.

Figure 2. Hot ice cream is made from cream, milk, water, sugar, vanilla extract, and methyl cellulose.

Figure 3. Mixing the cream, milk, water, sugar, and vanilla extract results in about half a liter of base solution.

2. Heat the base slightly, about one minute on the highest setting in the microwave. Methyl cellulose dissolves better in a lukewarm liquid.
3. Label containers as shown in Figure 4. You should have a container for each: a 2%, 3%, and 4% ice cream solution.

Figure 4. Label containers for 2%, 3%, and 4% hot ice cream solutions.

4. Finish the three solutions by adding methyl cellulose.
   1. Take the 2% container.
   2. Look up the amounts of base and methyl cellulose needed for the 2% solution in Table 2.
      
      

      Recipe	Amount base (g)	Amount methyl cellulose (g)	Technical note: % calculation
      2%	98.0 (or almost 100)	2.0	2/(98+2)= 2/100 or 2%
      3%	194.0 (or almost 200)	6.0	6/(194+6)= 6/200= 3/100 or 3%
      4%	96.0 (or almost 100)	4.0	4/(96+4)= 4/100 or 4%

      Table 2. Amounts of base and methyl cellulose needed to create a specific hot ice cream solution.
      
      
   3. Add the amount of base given in Table 2 to the container, followed by the indicated amount of methyl cellulose. The How to Use a Scale section can help you weigh the quantities accurately.
   4. With the fork, stir the methyl cellulose into the base until all clumps disappear.
   5. Repeat steps a–d for the 3% and 4% solutions. Note that you make more of the 3% solution as you will use this solution to explore the preparation of hot ice cream.
   6. You should have three different ice cream solutions now: one with 2%, 3%, and 4% methyl cellulose as shown in Figure 5.

Figure 5. Hot ice cream solutions ready to be stored in the refrigerator.

5. Close the containers and store them in the refrigerator for about 24 hours. This allows the methyl cellulose to dissolve and hydrate fully. If you can, take out the solutions and stir them once or twice during the resting time.
6. Figure 6 gives an example of how you can plan your experiment. As you can see, you can start testing the day after you made the solutions. If you need to wait another day or two, that is fine, too.

Figure 6. Prepare the solutions at least one day before you plan to perform the test.

Technical Note: How to Use a Scale

Figure 7. Set your scale to measure in grams (g) and zero out the scale with your container sitting on the scale before you start adding the ingredient you like to weigh.

Show step-by-step instructions

1. For scales that have a zero out (tare) function:
   1. Set the scale to measure in grams (g).
   2. Place the container you are using to measure on the scale and press the "zero out" or "tare" button. The scale should now indicate 0.0 g as shown in Figure 7.
   3. Add the ingredient to the container until the scale indicates the desired amount.
2. For scales that do not have the zero out function:
   1. Set the scale to measure in grams (g).
   2. Place the container you are using to measure on the scale and note its mass.
   3. Add the mass of the container (measured in step b) to the mass of the ingredient you want to measure. As example, if your container weighs 11 g and you need to measure off 200 g of water, the total mass of the container and water will be 211 g.
   4. Add the ingredient to the container until your scale indicates the amount calculated in step c.

Determining the Best Cooking Time

Time to cook and explore! In this section, you will experiment and determine the best cooking time for your 3% solution.

1. Take the 3% solution out of the refrigerator. Stir well and let it adjust to room temperature for about one hour.
2. Put a sheet of millimeter graph paper in a plastic holder as shown in Figure 8.

Figure 8. Millimeter graph paper protected by a plastic holder will be used to measure how fast the hot ice cream scoops melt.

3. Place the covered paper on a flat surface near the microwave. Molten ice cream scoops tend to be rounder puddles when you work on a flat surface, and round puddles are easier to measure.
4. Choose a microwavable round measuring spoon (with a clear, deep scoop) that holds exactly one tablespoon to scoop out a tablespoon of solution. Level off the top as shown in Figure 9.

Figure 9. A microwavable, deep tablespoon is used to scoop up the solution and make a nice-looking hot ice cream scoop.

5. Place the measuring spoon in the middle of the microwave, as shown in Figure 10. Always place the spoon at the same location for each trial.

Figure 10. The scoop of hot ice cream is cooked for a short time in the microwave on low power.

6. Microwave for 1:30  minutes (min) on power level 3. The hot ice cream is better when cooked slowly.
7. When you take the spoon out, let the cooked ice cream rest inside the spoon for 30 seconds. Figure 11 shows the different steps on a timeline.

The timeline for an experiment begins with a scoop being placed in a microwave with a cooking time between 30 seconds to 5 minutes. After the microwave is stopped, 30 seconds are allowed for the scoop to rest before being transfered to a sheet of paper. Observations are made directly after the scoop is placed on the paper.

Figure 11. Give the ice cream 30 seconds rest time before transferring it to the paper.

8. Turn the spoon over on the protected graph paper. The scoop will most likely fall out of the spoon, as shown in Figure 12. Below some tips:
   1. If the scoop falls apart or if the solution is still too liquid, try again with a slightly longer cooking time.
   2. If the ice cream sticks to the scoop, you can slide a different spoon around the edges to loosen the hot ice cream scoop as shown in Figure 13.
   3. Place the scoop near the middle of the paper and not at the edges, as it is going to melt and increase in size.

Figure 12. Transferring a spoon of cooked hot ice cream to the protected graph paper.

Figure 13. If the scoop does not slide out by itself, try sliding a different spoon around the edges of the cooked ice cream scoop.

9. Take a moment to observe. How does the scoop look when still hot? Is it appealing and appetizing?
10. Observe how the scoop melts; this can take up to 20 minutes. Does the scoop melt fast, or does it take quite some time? Is the molten cream like a sauce, appetizing, thick, or thin?
11. With your observations in mind, think about what you like to obtain. How quickly or how slowly should the scoop melt? Think about where and how it would be used. Should it melt instantly, or is there time needed for serving?
12. Time to experiment! Explore how different cooking times get you closer or further from your ideal. A table like Table 3 will help you record your observations.

    Note: If your results do not look good after a few trials, try switching to a slightly higher microwave power.

13. You can place several scoops on the same paper as long as they are not touching each other. If you need more space, throw out molten scoops and clean your plastic-covered graph paper with a paper towel to make room for new scoops.
14. Explore until you feel satisfied with a specific cooking time, or until you used up half of your 3% solution. If you are still unsatisfied with the results, choose the time that you feel is best. Testing the other solutions might help you reach your goal.

Comparing Different Recipes

In this section, you will take detailed measurements of how fast the ice cream scoops of the 2%, 3%, and 4% solutions melt when cooked for a specific time. What is your hypothesis? Note these measurements need to be done all in one sitting. If you are afraid there might not be enough time left, take a break now and come back to it later.

1. Take all three solutions out of the refrigerator. Stir well and let adjust to room temperature for about one hour.
2. Clean your plastic-protected graph paper and place it back on the flat surface near the microwave.
3. Copy table 4 in your notebook. It will help record your measurements. Remember to fill in the cooking time you established in section "Determining the Best Cooking Time."

4. To see how fast a scoop melts, you will measure how the dimensions, or diameter, of your scoops changes over time. Specifically, you will measure the scoop diameter after 0, 10 and 20 minutes. Figure 14 shows each step on a timeline.

The timeline for an experiment begins with a scoop being placed in a microwave. After the microwave is stopped, 30 seconds are allowed for the scoop to rest before being transfered to a sheet of paper. Observations are made directly after the scoop is placed on the paper. Measurements are taken immediately after the scoop is transfered to the paper, 10 minutes after the initial transfer and 20 minutes after the initial transfer.

Figure 14. In this section, you cook the hot ice cream for a fixed time, then let it rest for 30 seconds before transferring it and take a measurement just after transferring (0 minutes), after 10 minutes of melting, and after 20 minutes of melting.

5. Define the diameter of a scoop, or measure its size.
   
   Figure 15. This project defines the "diameter" of a scoop as the average of the largest horizontal distance of the scoop (shown in the top graph, referred to as horizontal diameter) and the largest vertical distance of the scoop (shown in the bottom graph, referred to as vertical diameter).
   
   See these detailed instructions on how to measure the diameter.
   Show step-by-step instructions

   1. Measure the diameter of the scoop depicted in Figure 16. Can you see it is 48  millimeters (mm), or 48 little cages long? Do you see how it is nice and round? Whether you counted in the horizontal direction or the vertical direction, or in any other direction, you obtained the same number of little cages. Note each little square is 1 millimeter long and 1 millimeter wide.
      
      
      
      Figure 16. A round scoop of hot ice cream has a clear diameter. The largest distance measured horizontally (top figure), vertically (bottom figure), or in any other direction provides the same value.
      
      
   2. Now, measure the diameter of the scoop depicted in Figure 15. This scoop is not nice and round. If you measure the longest distance in the horizontal direction, you get 45  mm. The longest distance in the vertical direction is 48  mm. For this project, you will record these values (45 and 48) as "horizontal diameter" and "vertical diameter" in your data table.
   3. After all measurements are done, you will calculate the average of the measured "horizontal diameter" and "vertical diameter," as this is a good indicator of the area the scoop (or molten puddle) covers on the paper. To calculate the average, divide the sum of the two measured values by two. Table 5 lists the calculated diameters for the scoops shown in Figures 16 and 15 respectively. You can use a calculator if you have difficulty calculating the average value.

   
   

   Horizontal [mm]	Vertical [mm]	Average calculation [mm]	Average [mm]
   48	48	(48+48)/2	48
   45	48	(45+48)/2	46.5

   Table 5. Calculate the average value of the two measured diameters.

6. Take a scoop of your 2% solution, and cook it as you did previously for the time duration established in section "Determining the Best Cooking Time." It is very important to stick to one cooking method (scoop size, cooking time, microwave power, and rest time) for all measurements.
7. Set your timer to 10 minutes. Then, start the timer after you transferred the scoop to the covered graph paper.
8. Measure the initial diameter of the scoop. Optional: Instead of measuring now, you can take a birds-eye picture of the scoop and count the cages it covers later, when you review the pictures. If you do so, remember to include a label in your picture, as shown in Figure 17.

Figure 17. When taking pictures, take a birds-eye view and include a label of what is in the picture. Pictures can help you take accurate data.

9. Measure again when the timer indicates 10 min and set your timer to 10 minutes again. Once the second 10 minutes is over, measure the scoop diameter for the 20 min time point.
10. Record your data in your data table.
11. This ends the first trail for the 2% solution. Repeat steps 6–10 for the 3% solution, and again for the 4% solution.
12. Repeat steps 6–11 three more times, for a total of three trials.
13. Your data would not be complete without a taste test! Copy Table 6 in your notebook, cook a sample of the 2% solution, and taste the sample at the 10-minute melting point. Repeat for the other two recipes. Note your observations on taste and texture in your table.

Analyzing Your Results

1. Calculate the average diameter of each scoop by adding the horizontal and vertical diameter and dividing the sum by 2. If you need help, look back at the examples in section Learn how to measure the diameter. Note your results in a table like Table 7.

2. Calculate the average diameter over the three trials for 1 specific recipe. As an example, add the three initial average diameters for the 2% solution, and divide the sum by 3. This yields the total average initial diameter for the 2% solution. Record the total average values for this recipe in the average row in your data table like Table 7.
3. Optional: You might see how one solution melts faster than another, or how its average diameter grows faster. This trend can be made even more explicit when using the relative diameter, which tells you how much the diameter of the scoop changes over time compared to its original size. To calculate the relative diameter, divide the average diameter at a time point (initially, 10 minutes or 20 minutes) by its initial average diameter. As an example, if you measured 48 mm initially, 62 mm after 10 min., and 96 mm after 20 min., the relative diameters would be 48/48=1 initially, 62/48 =1.5 for the 10 min. mark and 96/48=2 for the 20 min. mark. This means that the diameter of the scoop at 10 minutes is 1.5 times bigger than the original one, and the molten scoop at 20 minutes has a diameter that is twice the size compared to the beginning. Copy a table like Table 6 in your notebook, calculate the relative average diameters, and note them in your table.

4. Make a bar graph with the time points (0, 10, and 20 minutes) on the horizontal axis and the average diameter on the vertical axis. You can make a graph for each recipe (2%, 3%, and 4% methyl cellulose) or use one bar graph with different colors indicating the different recipes. The Bibliography lists an online graphing tool that can help you create graphs.
5. Optional: If you calculated the relative diameter, graph the relative diameter (vertical axis) for each time point (horizontal axis). Use one bar graph with different colors indicating the different recipes.
6. Looking at your graph(s) and your data tables, what can you conclude? Do you see any trends? Does one solution melt faster than another?
7. Looking at all your data, notes, and observations, which recipe and cooking time do you think is best-suited for restaurant use of hot ice cream? Which recipe would you serve your guests if you were a chef in a restaurant?