Homemade Pudding

Homemade Snack Packs: Chocolate Pudding

A side-by-side comparison of the final product, after 8 hours of cooling in the refrigerator. 

 

The majority of ingredients required to make the pudding. 

The two pans used to cook the pudding, on their respective burners. Red pot contained the pudding with all-purpose flour, and the black pot contained the control pudding with the cornstarch.

The control batch of pudding containing the cornstarch, at the 11:34 minute mark.

The test batch of pudding containing the flour, at the 11:34 minute mark. At this time, the pudding began to release heat in the form of steam, and shortly after began to bubble, allowing for the final ingredients to be incorporated into the mix. 

The final pudding mixture of the control batch, right after it was removed from the stove.

The final pudding mixture of the test batch, right after it was removed from the stove.

For my last experiment, I had absolutely no idea what I was going to make. I spent at least an hour and a half flipping between our book’s table of contents and the various recipes provided within it, and for whatever reason, the recipe I kept going back to was the one for creamy chocolate pudding. So it was at that time, I decided that I would attempt to make creamy chocolate pudding from scratch, a dish that I have never made before.

I began my chocolate pudding endeavor by first acquiring all the ingredients from my local grocery store. The list of ingredients for this recipe included the following:

·         2 teaspoons vanilla extract

·         ½ teaspoon instant expresso

·         ½ cup sugar

·         3 tablespoons Dutch process coca

·         1 teaspoons cornstarch

·         ¼ teaspoon salt

·         3 large egg yolks

·         ½ heavy cream

·         2 ½ cups whole milk

·         4 ounces bitter sweet chocolate

·         5 tablespoons unsalted butter, cut into 8 pieces

According to ingredient list, 1% and 2% milk could be substituted for whole milk, however the pudding would be slightly less rich in flavor if 2% or 1% milk were used. Since the grocery store I bought my supplies from did not have whole milk available, I substituted 2% milk in its place.

Since this recipe came from the section of the book that talked about starch and its ability to prevent eggs from curdling in pastries, soups, and puddings, as well as that the book had stated that in certain cases, flour could be substituted for corn starch, this experiment will focus on the starch added to the recipe. The book also stated that, specifically for the chocolate pudding, flour could be substituted for corn starch in the recipe, however a larger portion of flour would be need, but did not say how much the portion would be increased. Thus, since this was not stated, I substituted the same amount of flour in my test batch of pudding, as the amount of corn starch that was added to my control group of pudding.

My hypothesis for this experiment was that if you use flour instead of corn starch while making pudding, then the pudding made with the flour will be less dense/thick than the pudding make with corn starch, because flour contains less starch than corn starch. Thus, requiring a large amount of flour be added to the recipe.

My null hypothesis was that the type of starch used would not have any effect on the pudding.

My independent variables were the type of starch used—Corn starch vs. all-purpose flour.

My dependent variables were the thickness of the pudding, the amount of time it took to cook the pudding, and the temp. the pudding reached when it was complete.

The standard variables for this experiment were the pots used to cook the pudding (similar pots), the stove used for heating, the heat setting used to cook the pudding (both burners were turned to the middle mark on medium), the stopwatch used to keep track of time (www.online-stopwatch.com), and the thermometer used to take the temperatures of the pudding, the amount of time the puddings were allowed to cool (8 hours) and the rating scale used to rate the thickness of the puddings (1 being of soup consistency, 5 being peanut butter consistency).

After I acquired all the ingredients for this tasty dish, I began my experiment by laying all the ingredients out on my kitchen counter. Once this was complete, I gathered 5 medium sized bowls, a cutting board, a knife, two similar pots, a Wisk, and various measuring cups/spoons. Once I had all my cooking utensils in order I began to assemble the ingredient mixtures.

For this I started by measuring out 2 different batches of 2 teaspoons of vanilla extract and ½ teaspoon of instant espresso, into two separate bowls, one for each batch of pudding, since this ingredient combination would be the last thing added to the pudding. Once this was complete, I measured out ½ cup of sugar, 3 tablespoons of coca powder, 2 teaspoons of cornstarch, and ¼ teaspoon of salt into one of the pots, that I had placed on the stove top, while the stove was still off. This dry mixture was placed in the black pan, and would serve as the dry mix for the control batch of pudding that used the recipe provided from the book. I then measured out a second dry mix batch, consisting of the same quantities of the same ingredients, with the exception of 2 teaspoons cornstarch.  In its place, I substituted 2 teaspoons of all-purpose flour, in order to create the dry mix for my experimental batch of chocolate pudding. This dry mix was placed in the red pot, which I had placed on the stove top, while it was still off.

Once the dry ingredients had been measured out and placed in their respective pots, I than prepared the wet ingredients. These included ½ cup of heavy cream, 2 ½ cups 2% milk, and 3 egg yolks for each batch. Before I added the wet ingredients to the pots, I took the time to prep one other set of ingredients, since they would have to be mixed in as the pudding began to bubble, and time would be important to prevent the pudding from burning.  Thus, I cut up two separate portions of 4 ounces of bitter sweet chocolate, and two separate portions of 5 tablespoons of unsalted butter. A combination of 4 ounces of diced bitter sweet chocolate, and 5 tablespoons of unsalted butter were then place in two separate bowls, for convince, when they would be added at the later stage of cooking.

Once the final ingredients were prepped, I whisked in the premeasured wet ingredients into both of the batches of pudding, and turned the burners on to the middle notch on the medium heat setting. At this time, I also started the stop watch.  The mixtures were continually whisked while being heated, just as instructed. The instructions also stated that the mixture needed to be heated until it bubbled across its entire surface before the chocolate and butter could be added, followed by the final ingredients of vanilla extract and instant espresso. As the mixture started to heat, I noticed a few differences between the two batches, and thus recorded the time at which each batch began to release steam, and the temperature at which both batches where at during this time, in comparison to one another. That is, the pudding containing the all-purpose flour started to release steam after 11:34 minutes of cooking, and had reached a temperature of 177.8 degrees Fahrenheit, while at the same point in time, the batch containing the corn starch did not show any signs of heat release, and had only reached a temp of 137.7 degrees Fahrenheit.   

In addition, the batch containing the all-purpose flour appeared to cook much faster, and thicken up faster than the batch containing the corn starch. This was observed in the total time it took each batch to completely cook, which was completed when all ingredients were fully incorporated into the bubbling batches. The flour pudding took 25 minutes to fully cook, while the batch containing corn starch took 42 minutes to cook. One of the limitations to this finding was that, I had inadvertently place the pans on two different sized burners. The pudding  batch containing the flour was on a slightly larger burner than the pudding containing the cornstarch, and this could have resulted in a faster cooking time, simply out of the fact that the flour batch was in a pan that was in contact with a larger heated surface, were as the cornstarch batch was located in a pot where the heat was more concentrated in the middle of the pan.

As mentioned, the batch containing the flour began to bubble at 11:34 minutes, and at that point, the chocolate and butter ingredients were whisked into the pudding until they were fully incorporated. Once these ingredients were fully incorporated, the final ingredients of vanilla extract and instant espresso were incorporated into the pudding, and the pudding was removed from the heat source, and temp. taken. The final temp of the pudding containing flour was 190.3 degrees Fahrenheit. The same last sequence of steps were followed for the pudding containing cornstarch, when it finally bubbled all, which occurred after roughly 36 minutes of heating. The final temp of the pudding containing corn starch was 180.3 degrees Fahrenheit, with a final cook time of 42 minutes.

Both batches were then removed from the pots, and placed in two separate labeled bowls and place in the refrigerator overnight to cool for 8 hours. After 8 hours of cooling, the puddings were removed from the refrigerator, and tasted and rated on a scale of 1-5 with 1 being of liquid consistency (comparable to soup), and 5 representing fully thick pudding (comparable to peanut butter).

After administering this highly subjective test, I determined that both batches were fully thick, both with consistencies that were comparable to peanut butter. I than had my roommates blindly compare the two batches, and their ratings appeared to support this as, both batches received scores of 5 from both gentlemen. This data is represented in the charts and graphs below, as well as the time and tem data.

Thickness Rating Data	Pudding containing Cornstarch	Pudding containing Flour
Tester #1	5	5
Tester #2	5	5
Tester #3	5	5

Temperature Data-in degrees Fahrenheit	Pudding containing Cornstarch	Pudding containing Flour
After 12 minutes of heating	137.7	177.8
Final temperature	180.3	190.3

Total Cook Time Data—in minutes	Pudding containing Cornstarch	Pudding containing Flour
Time to fully cook	42	25

This graph represents the thickness ratings given to each of the two batches of pudding by three separate individuals. Thickness was rated on a scale of 1-5, with 1 representing a liquid consistency comparable to that of soup, and 5 representing a thick consistency comparable to that of peanut butter. All individuals stated that the consistency of both batches of pudding were identical, and this was observed by there ratings of 5s for both puddings. 

This graph represents the difference in total cook time each batch took to reach the point at which all ingredients were incorporated into the pudding. As can be observed by the graph, the pudding containing flour instead of cornstarch, required almost half as less time to fully cook, than the pudding containing the cornstarch did. While there was a notable difference in the amount of time required, this data may have been dramatically skewed by the fact the each pot was placed on a different size burner, on the same stove. The pudding containing the flour was inadvertently placed on a larger burner than the pot containing the pudding with the cornstarch, which may have caused it to cook faster in general, as compared to the difference in cook time resulting for the difference in ingredients. 

Overall, the pudding turned out very flavorful, and both were very think as already mentioned. While there appeared to be a few differences among the two batches while they were being heated, after cooling both batches appeared to be the same. A few things I would fix if I had to do this experiment again would be to place the pots on the same size burner, in order to get a better gauge as to whether there really is a difference in the amount of time it takes the pudding to cook, for reasons already mentioned. In addition, I would also completely eliminate starch from one batch of pudding, to use as a test group, in order to have a better comparison, to see just how much starch affects a dish like this. In addition, I also would have increased the number of batches made, had more than 4 people test it, and incorporated a less subjective means of testing it's thickness. 

Now that we have discussed the experiment, lets discuss the since behind the importance of starch when it comes to cooking dishes like this.  According to our book, The Science of Good Cooking, eggs appeared to be the delicate ingredient in pastry/soups/custard style dishes that can have a dramatic impact on the texture and consistency of these types of dishes (Editors of Cook's Illustrated & Crosby, 2012). Moreover, it is the way that eggs coagulate, that can either make or break a dish like these, as the rate at which eggs coagulate is directly related to the amount of heat introduced (Editors of Cook's Illustrated & Crosby, 2012). Too much heat and the eggs coagulate into a structure that is so extensive and strong, that the water is actually squeezed out, resulting in the formation of curds (Editors of Cook's Illustrated & Crosby, 2012). While there are various ways to affect the coagulation point of eggs, the chapter focused on the ability of starch to increase the temperature at which eggs coagulate (Editors of Cook's Illustrated & Crosby, 2012).

According to the chapter, primarily cornstarch, and in some dishes flour are needed to increase the coagulation temperature of eggs (Editors of Cook's Illustrated & Crosby, 2012). Cornstarch, in some instances flour, achieve this effect because starch granules release spindly threads of amylose when heated, that interfere with the cross-linking of proteins, and thereby increase the temperature at which eggs coagulate (Editors of Cook's Illustrated & Crosby, 2012). This is very important when it for the stabilization of egg proteins when they are heated, and helps prevent them for clumping and curdling in creamy dishes such as pudding (Editors of Cook's Illustrated & Crosby, 2012). Which is why both puddings were free of clumps and curds. In addition, the increased coagulation temperature allows the puddings to be cooked for much longer and to reach a higher temperature, while remaining clump and curd free, than they would have otherwise had the starch not be added. Which in turn, also makes puddings and custards very thick, which helps explain why my puddings were both very thick (Editors of Cook's Illustrated & Crosby, 2012). Finally, four was a reasonable substitute in this instance, because flour contains 75 % wheat starch, which is similar to cornstarch, simply less concentrated than cornstarch (Editors of Cook's Illustrated & Crosby, 2012). This also helps explain why there was no difference in thickness between the two batches of pudding I made (containing cornstarch vs. flour).

Source Citation:

Editors of Cook. , & Crosby, G. (2012). The science of good cooking. Brookline: Cook's Illustrated

Juicy Fruit: Why sugar is added to fruit.

Juicy Fruit: Why sugar is added to fruit.

Since our last two mini-experiments, for our Science of Food and Cooking course, require us to choose a recipe from our textbook, and to refer to the science concepts behind them, I began my experimental search by browsing over the table of contents. One of the concepts that caught my eye was concept 49, which was tilted Sugar and Time Make Fruit Juicer. My interest was caught by this concept, because fruit is often already very sweet, and I just could not understand why anyone would want to add more sugar to it and make it even sweeter. After skimming the material, I learned that adding sugar to fruit actually makes it juicer, something I will explain later on in this blog.

I then turned my attention to the test procedure the authors of our textbook had provided in demonstrating this interesting concept. In the textbook, the authors’ test consisted of cutting 4 ounces of strawberries, into ¼ pieces, tossed them in 1 tablespoon of sugar, plied them in the middle of a napkin, and measured how far the juices had spread over a period of 15 minutes, with data being recorded in 5 minute intervals. They also place 4 ounces of cut strawberries on a separate napkin to serve as a control.

I decided to replicate this test, with the addition of a group of strawberries that had been tossed in 1 tablespoon of salt, in addition to the group tossed in sugar, and the control group. I also decided to collect data over a 25 minute period instead of 15.

My hypothesis for this study was that adding sugar to cut strawberries would cause them to release more liquid, then strawberries that were plain, because the sugar would cause an osmoses reaction to occur and draw the liquid out of the fruit.

My null hypothesis was that added sugar, and salt, would not affect the amount of liquid that was released by the strawberries, and then absorbed by the napkins.

My independent variables for this experiment were strawberries tossed in sugar (sugar) and strawberries tossed in salt (salt).

My dependent variable for this experiment was the amount of liquid released by the strawberries, which translated into how far the liquid had traveled on the paper towels.

My standard variables were the number of strawberries place on each paper towel (16 ¼ cuts), the amount of time each measurement was taken (5 minute intervals), the total time of the test (25 minutes), the measuring tool used (a 12 inch ruler), the size of the paper towel (10.5 inches x 11 inches), the same brand paper towel, the amount of sugar (1 tablespoon), the amount of salt (1 tablespoon), and the stop watched used to keep track of time (www.online-stopwatch.com).

The materials for this test included:

·         12 strawberries of approximately equal size

·         1 tablespoon salt

·         1 tablespoon sugar

·         3 paper towels of the same size, from the same roll

·         2 separate bowls to toss the strawberries in either salt of sugar

·         A ruler

·         A stop watch

·         A knife

To begin my experiment, I first began by acquiring 12 strawberries of similar size. Following this, I then removed the leaves from the top of all the strawberries. Once this was completed, I than acquired 2 separate plastic bowls. In one bowl I measured out 1 table spoon of sugar, and in the other bowl I measured out 1 table spoon of salt. I than place 4 strawberries on 3 separate Styrofoam plates. At this point I laid out 3 separate paper towels on my kitchen table, and place note cards next to each indicating which would hold what test group.

Once everything was prepared, I than cut the strawberries in groups of four. The strawberries were first cut in half horizontally, and then those halves were then cut in half again horizontally. This meant that each strawberry yielded 4 pieces of roughly equal size, resulting in 16 ¼th pieces per test group. I then proceeded to repeat this process for the other two sets of strawberries. Once all strawberries were cut, I then tossed one group in the bowl of sugar, until the strawberries had soaked up all the sugar in the bowl. Following this, I did the same thing with the remaining group of strawberries, in the second bowl containing salt. At this point, I put on 2 sets of food service gloves in order to avoid contaminating any of the batches with residual salt or sugar from one another.

At this point, I place each group of strawberries on their corresponding paper towel, shedding gloves in between each group, until the final group was placed with my bare hands. Once all groups had been placed on their paper towels, I started the stop watch. At every 5 minute interval, I measured the diameter of the released juice on the paper towel with my ruler. Data was gathered for 25 minutes.

Group of Strawberries without anything added, on paper towel, at the 0 minute mark.

Group of sugar tossed strawberries, on a paper towel, at the 0 minute mark.

3 groups of strawberries, after they were cut into 1/4 sized pieces, before being treated in their respective conditioning agents (sugar and salt).

Group of salt tossed strawberries, on a paper towel, at the 0 minute mark.

Groups of strawberries, before being cut.

The paper towels that were used to demonstrate the juice released from the strawberries.

At 5 minutes in, the strawberries with no salt or sugar did nothing; the only visible marks on the paper towel were where the strawberries had initially come into contact with the paper towel. The sugar coated strawberries on the other hand, had a significant visual ring of water on the paper towel, while the strawberries tossed with salt had a visible ring around them, but smaller compared to the sugar. By 10 minutes, the rings had grown about an inch for the salt and sugar strawberries, while the control group still had not produce any changes. The surprise was that, at 15 minutes, the strawberries covered in salt had begun to release more liquid than the strawberries covered in sugar. This continued until the end of the experiment. The diameter of the water marks for each group were as follows:

Time	Control- Nothing added	Strawberries tossed in sugar	Strawberries tossed in salt
5 minutes	N/A -  only initial contact marks	4 inch	3 inch
10 minutes	N/A- only initial contact marks	5 inch	4.5 inch
15 minutes	N/A- only initial contact marks	5.5 inch	6 inch
20 minutes	N/A- only initial contact marks	6 inch	7 inch
25 minutes	N/A- only initial contact marks	7 inch	8 inch

As you can see by the data, sugar did in fact cause the strawberries to become juicer than strawberries with nothing added. However, the data indicates that salt was had a greater effect on the strawberries than the sugar. After I some more of the science behind this phenomena, I learned that sugar has 1/10 the power of sugar in terms of causing this effect (Editors of Cook's Illustrated & Crosby, 2012). This explains why the strawberries tossed in salt started releasing more liquid than the ones tossed in sugar. A point of interest, was that while the strawberries tossed in salt released more overall liquid than the strawberries tossed in sugar, the liquid on the paper towel of the strawberries tossed in sugar seemed to be more concentrated juice, as it was much redder, and thicker than the water on the paper towel with the strawberries tossed in salt.

The graph above demonstrates the diameter of the water marks made by the juice released from each of the test groups of strawberries (salt, sugar, and control). The diameter of the water mark was measured in inches over a 25 minute period, with measurements taken in 5 minute intervals. The control group does not have a visible bar, because the juice collected on the paper towel, was only that of the initial contact made with the paper towel upon placing them there, and was measurable.  In turn, since the control data was not applicable, it was recorded in the data collection as 0 for each of the intervals. The red bars represent the juice released by the sugar tossed strawberries, and the blue bars represent the juice released by the salt tossed strawberries. 

A picture of the final water mark left on the paper towel, made by the control group of strawberries at the 30 minute mark. 

A picture of the final water mark left on the paper towel, made by the control group of strawberries at the 30 minute mark. 

An up close picture of the surface of the control group of strawberries at the 0 minute mark. 

An up close picture of the surface of the sugar group of strawberries at the 0 minute mark. 

An up close picture of the surface of the salt group of strawberries at the 0 minute mark. 

A picture of the final water mark left on the paper towel, made by the sugar group of strawberries at the 30 minute mark. 

Now that we have discussed the experiment, let now examine the scientific aspect behind why these results occurred. According to concept 49, when sugar is added to fruit, it produces osmotic pressure, which in turn pulls the water out of the fruit’s cells (Editors of Cook's Illustrated & Crosby, 2012). The reason sugar creates this osmotic pressure is, because sugar is hygroscopic, which means that it has a high affinity for water molecules (Editors of Cook's Illustrated & Crosby, 2012). In fact, sugar is so hygroscopic, it can even draw moisture out of the surrounding air (Editors of Cook's Illustrated & Crosby, 2012). The process by which sugar draws the water molecules out of fruit is call maceration, which not only draws the moisture molecules out of the fruit, but also changes the texture of the fruit by making them softer and less waterlogged (Editors of Cook's Illustrated & Crosby, 2012). This textural change occurs, because cells that are filled with ware are firm and more ridged, while cells that contain less water become flaccid, and in turn softer, which is similar to that of a wilted plant when it begins to dry out (Editors of Cook's Illustrated & Crosby, 2012). Once maceration occurs, the resulting liquid can be used to moisten dishes like fruit salads or fruit cakes since it is a very flavor rich liquid, or it can simply be discarded to prevent keep baked goods such as crumbles or pies from becoming too soggy (Editors of Cook's Illustrated & Crosby, 2012).

If I were to do this experiment again, one of the things I would do differently would be to cut the strawberries into smaller pieces. The ¼ sized pieces were simply too large, making them hard to pile in the center of the paper towel, which also made it kind of hard to measure how far the liquid had spread.

In addition, it was not until after I had completed the experiment did I realize that we were supposed to cook a dish using a recipe from our textbook, instead of conducting a test to demonstrate a scientific concept. So for the final experiment, I will not make this same mistake.

Source Citation:

Editors of Cook. , & Crosby, G. (2012). The science of good cooking. Brookline: Cook's Illustrated

Are all Potatoes created the same?

Are all Potatoes created the same?

Raw potatoes corresponding to their respective food dye colors--Blue--Yukon Gold, Red--Red Bliss,and Green--Sweet Potato.

Potatoes cooking on the stove, in their respectively dyed water.

Just for fun. All the potatoes placed together, once data was collected.

Yukon Gold potatoes cut open, after they were cooked for 10 mins. As you can see the dye was absorbed all the way to the core of the potato, thus showing their high starch content.

Red Bliss potatoes cut open, after cooking. As you can see the dye was absorbed only 2mm into the outside of the potato, which formed a small red ring around the outside.

All the potatoes, on plates, before they were cut open, and data gathered.

Sweet potatoes cut open, after cooking for 10 mins. As you can see, the green dye only traveled 1mm into the potatoes. This demonstrated that Sweet potatoes also have a very low starch content. 

For my third mini-experiment, given the fact that I had kind of ran out of ideas for things to test, and because I wanted to start to test something’s that might not be so obvious as the concepts I had already tested, I decided to explore the chapters in my The Science of Good Cooking text book for some ideas. In addition, I also wanted an experiment idea that would produce a large sample size than a 1 on 1 comparison, as well as a test that would be quantifiably measurable. One of the categories that caught my eye was the sections on potatoes. When I saw the word potatoes, I immediately thought “hey I could get a lot of samples out of those potatoes, for a relatively inexpensive price, and no matter what I was going to do it wouldn’t take very much time.” The first experiment I read up on dealt with the temperature of hot oils used for frying. However, that was something that was somewhat obvious, and I wanted to test a concept that I really had never heard about before and that was more interesting. With that said, I settled on the experiment that explored the density of different varieties of potatoes in terms of their starch content.

According to concept 25 (chapter 25), all potatoes are not created equal. While potatoes consist of 2 main components—starch and moisture—the density of each particular type of potato is directly correlated to the amount of starch it has, which can range from 16% to 22% (Editors of Cook's Illustrated & Crosby, 2012). Furthermore, the amount of starch each potato possesses affects a variety of things with its two most important characteristics being the potato’s ability to hold shape and fluffiness (Editors of Cook's Illustrated & Crosby, 2012). When potatoes are cooked, the granules inside them absorb water from within the potato, which causes the potato to swell similar to that of a balloon, which in in turn causes the cells inside the potato contain the granules to expand, separate, and burst (Editors of Cook's Illustrated & Crosby, 2012). And with continued cooking, the swollen granules that have not let burst, end up bursting, which in turn release some of the entrapped starch (Editors of Cook's Illustrated & Crosby, 2012). In the end, the more starch a potato contains, the more burst potato cells potato will have (Editors of Cook's Illustrated & Crosby, 2012). And one of the ways to test how much starch a potato has is to dye the water it is being cooked in with food coloring.

My hypothesis for this experiment was that if we tested the amount of starch in 3 types of potatoes—Yukon Gold, Red Bliss, and Sweet Potato—by cooking them in colored dye, then potatoes with a higher starch content would absorb more food coloring than potatoes with a lower starch content, because potatoes with a higher starch content would have more burst granules, and would therefore be able draw in more liquid during the cooking process.

My null hypothesis was that the amount of starch in each type of potato would have no effect on the amount of food coloring drawn into each potato.

My independent variable for this experiment was the type of potato used—Yukon Gold, Red Bliss, or Sweet Potato.

My dependent variable for this experiment was the amount of starch each potato contained, which translated into the amount of food dye color that was absorbed by each potato.

My standard variables for this experiment included: the size of the potato cubes being cooked (30mm x 20mm x 5mm), the temperature of the boiling water (210.5 degrees Fahrenheit),  the number of potato cubes tested (5), the amount of cook time and rest time (15 minutes and 10 minutes respectively), the measuring instrument (a 12 inch ruler with metric marks), the amount of potato cubes per each type of potato (5 cubes), and finally the food dye colors used for each potato (blue-Yukon, red- Red Bliss, and green-Sweet potato).

After acquiring my 3 types of potatoes from the grocery store, I took 3 pots out of my kitchen cabinets, filled them with water, and placed them on top of my stove over high heat to boil. While the water started to boil, I rinsed each potato under cold water, to clean any remaining dirt off the outside of the potato. Following this, I cut each type of potato into 30mm x 20mm x 5mm cubes , and placed them next to their corresponding dye color that I had selected. Before dying the water, I took the temperature of the water in each pot to ensure that they were all roughly about the same, which was indeed the case as the water in each pot had reached 210.5 degrees Fahrenheit. At this point I dyed the water in each pot a different color—blue, red, and green—and placed the corresponding potatoes in each pot—Yukon Gold, Red Bliss, and Sweet potatoes respectively. At this time, I left the potatoes to boil over high heat for 15 minutes. Upon completion of the 15 minute boil time, I removed all pots from the stove and allowed the potatoes to cool for 10 minutes. Once the potatoes had cooled, I removed each type of potato from their pots, and placed them on separate Styrofoam plates. At this time I cut each potato open and measured how far the colored dye had traveled into the potato. The results were as followed:

Yukon Gold	Red Bliss	Sweet Potato
5mm	2mm	1mm
5mm	2mm	1mm
5mm	2mm	1mm
5mm	2mm	1mm
5mm	2mm	1mm

This graph displays how far the food coloring traveled (in millimeters) into each type of potato after being boiled for 15 minutes, and cooling for 10 minutes. As one can observe from the graph, the dye traveled the farthest in the Yukon Gold potatoes at 5 millimeters, followed by Red Bliss at 2 millimeters, and lastly Sweet potatoes at 1 millimeter. The distance traveled correlates to the amount of starch in each type of potato. Thus, Yukon Gold potatoes have the highest starch content of the three types tested above, followed by Red Bliss and then Sweet potatoes respectively. The error bars are not displayed on the chart, because there was no variation or deviation among the samples collected for each type of potato.  

Yukon Gold potatoes appear to have the most amount of starch as the food dye had traveled completely into the potato all the way to the core. The next highest starch content appears to be in the Red Bliss Potato, as the dye had formed a 2mm ring of coloring around the outside of the potato. While this indicates that there is very little starch in the Red Bliss potato compared to the Yukon Gold potato, in comparison of the 3 types, it was the second highest starch content. Finally, the food coloring had only managed to travel 1mm inside the sweet potato, leaving a 1mm green ring around the outside of the potato, which indicated that sweet potatoes had the least amount of starch out of the 3 types of potatoes. 

The science behind this experiment is as follows: The first important aspect deals with the ratio of starch to moisture that each potato has (Editors of Cook's Illustrated & Crosby, 2012). The more starch a potato has, the more dense it is, and the great the propensity it has to absorb liquid (Editors of Cook's Illustrated & Crosby, 2012). This is because the starch granules have a greater propensity to absorb water as they are cooked, which causes them to swell, and also causes the other cells in the potato to separate from one another, and even burst, thus drawing in the food coloring (Editors of Cook's Illustrated & Crosby, 2012). Thus, the higher starch potatoes absorbed more food dye than the lower starch potatoes (Editors of Cook's Illustrated & Crosby, 2012).

Secondly, the ratio of each type of starch each potato has—amylose and amylopectin—determines the internal consistency of the potato (Editors of Cook's Illustrated & Crosby, 2012). Amylose is a long chain of starch that separates from swollen granules when exposed to heat, thus allowing for more fluid movement into the potato, and is also responsible for the fluffier texture of Yukon Gold potatoes (Editors of Cook's Illustrated & Crosby, 2012). The starch amylopectin, helps hold the potato tightly together when exposed to heat, thus diminishing the amount of outside moisture that is drawn into the potato when cooked (Editors of Cook's Illustrated & Crosby, 2012).

With that said, Yukon Gold potatoes had more overall starch compared to Red Bliss and Sweet potatoes in general, but Red Bliss and Sweet potatoes had a higher ratio of amylopectin starch compared to amylose starch, with Sweet potatoes possessing the highest ration of amylopectin. This was evident by the amount of dye that was absorbed by each potato. 

At this time, I am unsure of what I would do differently if I had to do this experiment over again. This was the smoothest any of my experiments have gone, and was actually quite simple. If I had to pick one thing, I would have to say that I would have cut the potatoes into larger cubes. The size I chose ended up being rather small after they were cooked, and it was a little hard to measure how far the dye had traveled. Thus, increasing the size of the cubes would have allowed me to make more accurate measurements, thus allowing me to detect minor differences.

Citation:
Editors of Cook. , & Crosby, G. (2012). The science of good cooking. Brookline: Cook's Illustrated