THE MELTING POINTS OF DIFFERENT CHOCOLATES

Caroline S

Cary Academy

ABSTRACT

The purpose of this experiment was to see if the type of chocolate determines the
melting point. The hypothesis for this experiment was that the unsweetened chocolate
would melt at the lowest temperature because it was the easiest to cut, melted the
fasted when placed in someone’s mouth, and when put in a microwave for 1 minute it
melted the most of out all the chocolates. This experiment was done by using a double
boiler, a double boiler is when there are two different sized containers (in this case a
beaker) the bigger on is used for holding a liquid and the other on is used to place
whatever object you are trying to melt. You put the smaller beaker inside the bigger
beaker. The double boilers were put on a hot plate to heat the water so the chocolate
would melt. A temperature probe was used to measure the temperature. After the
experiment was done it was concluded that the hypothesis was correct, the
unsweetened chocolate melted at the lowest temperature, followed by white chocolate
then semi-sweet. The first time the experiment was done the unsweetened chocolate
melted at 40 degrees Celsius, and the second time the experiment was done the
unsweetened chocolate melted at 34 degrees Celsius.

INTRODUCTION

In these experiments different types of chocolate are to going to be melted to answer

the question “does the type of chocolate determine the melting point”. The purpose of
this experiment to answer that question but also see what type of chocolate melts at the
lowest temperature.
Chocolate was first made by Mayan people about 3,000 years ago. The ways of making
chocolate have changed, now chocolate being sweeter. Chocolate is made with 2-3
main ingredients, but one object can be more than ingredient which is cacao beans.
Cocoa beans are the most important part of chocolate because cacao beans are what
give chocolate its taste. Cocoa beans can be made into cacao butter or cocoa powder.
To start the process of making chocolate cacao are gathered from cacao trees and
taken out of their pods. The beans are then sent to a factory to begin the lengthy
process of chocolate making. The beans are then piled into containers to roast. The
beans are roasted at very high temperatures. When the beans are roasting they get
their dark brown color and wonderful taste. After the beans are done roasting they go to
a machine to get cracked. At this point of the chocolate making process the bean shells
are cracked and then blown away, the only part left is the nib. The nib is what is inside
the cacao bean. The nib is made up of about 50% of a fatty substance called cacao
butter. The nib is then crushed by heavy steel disk that then create heat that melt the
butter. When the butter is melted and the other part of the nib is crushed it creates liquid
called cacao liquor. If one were to pour the cacao liquor into molds and then harden it
would be chocolate used for baking, which is very bitter and not very appetizing to eat
plain. To continue the process to get chocolate meant for eating plain, the next step it to
produce cacao powder from the cacao liquor. That is done by putting the cacao liquor in
a filter press then pressure is then applied on the cacao liquor. That pressure pushes
the cacao liquor through a piece of filter cloth. The filter cloth holds back solid particles,
when then are sifted and is cocoa powder. The chocolate liquid is then poured into
molds and then heated at very high temperatures. The chocolate then has it’s smooth
and soft texture as well as its taste. Chocolate meant for eating such as dark or melt
chocolate have added ingredients such as extra cacao butter, cocoa butter, milk, and
sugar. Though the process of making chocolate is very lengthy but the outcome is very
tasty!

There are 5 main types of chocolate in the United States. There is dark chocolate, milk
chocolate, white chocolate, semi-sweet chocolate/ bitter sweet chocolate, and sweet
chocolate. In the United States there is no standard requirement for dark chocolate, but
in Europe dark chocolate must have at least 35% cocoa solids in it. Dark chocolate
usually has barely any milk or sometimes no milk included at all, unlike in milk
chocolate. Dark chocolate can be eaten plain, or can be used for baking. When dark
chocolate is used for baking there is a certain kind of baking chocolate. Dark chocolate
used for baking can have 70%-99% cocoa in it. Dark chocolate is also referred to as
semi-sweet chocolate. Semi-sweet chocolate also called dark chocolate has half of
much sugar as it does cocoa. Bittersweet chocolate is not the same as semi- sweet
chocolate. As the names states bittersweet chocolate is very bitter and is mostly cacao
liquor. Bittersweet chocolate contains less sugar than semi-sweet chocolate, but more
cacao liquor. Bittersweet chocolate has very little sugar, less than a third. Bittersweet
chocolate is also referred to as extra dark chocolate. When baking bittersweet chocolate
and semi-sweet chocolate become the same and the outcome is the same with which
ever chocolate you use. Dark chocolate, semi-sweet chocolate, and bittersweet
chocolate are not as commonly eaten as milk and white chocolate because they are not
sweet. Milk chocolate must conceit’s of 10% chocolate liquor and 25% cocoa solids
because of United States requirements. Milk chocolate also consists of some type of
milk, whether its powdered milk, condensed milk, or liquid milk. White chocolate is
made of sugar, milk, and cocoa butter without cocoa solids in it. Sweet chocolate is
sweeter than semi-sweet chocolate because it has more sugar and cocoa in it. To meet
standards it must have 15% chocolate liquor in it. All chocolates have to have a certain
amount of cocoa in it to meet standards, so people can eat it.

When an object changes from a solid to a liquid, it melts. When a solid melts it is usually
applied heat. The solid must be heated until its meet its melting point. Melting point is
the temperature that a solid melts at. When a solid is heated its molecules start to
vibrate. When those molecules vibrate the create heat. Once the molecules have
vibrated enough to create the heat for the solids melting point, the solid starts to melt.
While the solid is melting the temperature is consistent. Once the solid has turned into a
liquid the molecules stop the vibrating and cool down.

In this experiment chocolate is going to go from a solid to a liquid. There are three main
types of states of matter, solid, liquid, and gas. All those types of matter are made from
atoms and molecules. An example of a solid liquid and gas would be a pillow, water,
and air. States of matter change from one form to another. One can change from one
form to another by the way the molecules and atoms move inside of side of the object.
Some objects can be all three states of matter, for example water. Water can be a solid
by being ice, can be a liquid being in its liquid form, or can evaporate and become a
gas. But even thought that the water is not in its liquid form, whatever state of matter it
is in it will always be water.

When observing the three different types of chocolates (semi-sweet, white, and
unsweetened) different observations were found. Both the unsweetened and semi-
sweet weighed 29.5 g while the white chocolate weighed 30 g. The unsweetened
chocolate had a very dark brown to almost black color. The white chocolate was a
creamy white color. And the semi-sweet chocolate had a deep brown color, but not as
dark as the unsweetened chocolate. When some volunteers tried the chocolate, they
had very different thoughts for each type of chocolate. For the unsweetened chocolate
the volunteers thought it tasted horrible, disgusting, and dissolved very quickly. For the
semi-sweet chocolate the volunteers said it tasted like sweet and a little milky. And
finally for the white chocolate the volunteers said it tastes very sweet and creamy. The
overall thought of the volunteers was that the white chocolate tasted the best. Then a
small piece of chocolate was placed in plastic cup and put in the microwave for 1
minute. The white chocolate melted most of the way, the semi-sweet chocolate was a
little melted, and the unsweetened was totally melted. Based on those observations the
hypothesis for this experiment is that the unsweetened chocolate will melt at the lowest
temperature. That is thought because the unsweetened chocolate dissolved very fast in
the volunteer’s mouths, and melted the most when placed in the microwave.

MATERIALS & METHOD

 1 block of white chocolate

 1 block of semi-sweet chocolate
 1 block of unsweetened chocolate
 1 temperature probe
  2 different size beakers, 80 ml and 250 ml
 125 ml of water
 125 ml of Coke, Diet Coke, and Sprite.
 1 hot plate
 1 tablet PC
 Safety goggles
 1 stirring stick
 Program logger pro
 Knife
 Paper Plate

Get the knife and paper plate and cut a small chunk of each type of chocolate and place
it in the 80 ml beaker. Fill the 250 ml beaker up with 125 ml of water and place on hot
plate. Before turning of the hot plate put on safety goggles for safety, in case the
experiment goes wrong. Turn hot plate on to setting 1. Get the temperature probe and
plug it into the tablet PC and open logger pro. Place the temperature probe in the bigger
beaker with water and measure until a constant temperature. Place the 80 ml beaker
with the chocolate on top of the other beaker filled with water. Wait to see if the
chocolates melt. If the chocolate does not melt after moving it around with the stirring
stick turn the hot plate up a temperature. Continue until chocolate starts to melt. If the
chocolate starts to melt immediately stick the temperature probe into the beaker with
water. Record temperatures. Repeat once again. Then repeat with the different
chocolates. The control in this experiment would be the semi- sweet chocolate because
it is most commonly seen and ate. The independent variable would be the type of
chocolate because you are changing the type of chocolate each time. The dependent
variable is the temperature in which the different chocolates melt at. When doing the
experiments, it was observed that before the chocolates melted they became a different
color and had a different texture.
In this follow up experiment the purpose was that the liquid is changed in the 250 ml
beaker to see if the liquid under the chocolates changes the melting point. It was
hypothesized that the diet coke would make the unsweetened chocolate melt at the
lowest temperature because it was the least bubbly, and because the unsweetened
chocolate melted the quickest in one’s mouth. When doing the experiment do the same
steps as above but when filling the 250 ml beaker up with 125 ml of water, fill 3 other
250 ml beakers with 125 ml coke, diet coke, and sprite. Record temperatures at which
the chocolates melt at. The independent variable for this experiment was the type of
liquid in the bigger beaker, because you are changing that to see if it makes a
difference. The control would be the water because that is the most normal, and it was
used for the first experiment. The dependent variable would be the temperature at
which the different chocolates melt at. Some observations from the experiment were
that the chocolate got a little bit of water around it when it got close to its melting point.

RESULTS & DISCUSSION

Figure 1: comparison graph for 1st experiment, melting point of different types of
chocolate
Above are the results of the first experiment with white chocolate melting at 40 degrees
Celsius, semi-sweet chocolate melting at 42.22 degrees Celsius, and unsweetened
chocolate melting at 37 degrees Celsius. The hypothesis was correct, unsweetened
chocolate melted at the lowest temperature. The experiment was done twice, with some
interesting data the second time around. The first time the experiment was done white
chocolate melted at 44.4 degrees, semisweet melted at 45.5 degrees, and the
unsweetened melted at 40 degrees. Then the second time the experiment was done the
melting points of each types of chocolate went down. The second time the experiment
was done the number went down. The second time the experiment was does white
chocolate melted at 35.7 degrees, semi-sweet melted at 39.6 degrees, and
unsweetened melted at 34 degrees. The difference between the two trials was 8.7
degrees for white chocolate, 5.9 degrees for semi-sweet, and 6 degrees for
unsweetened.

Figure 2: Graph for 2nd experiment, changing the different liquids in the double boiler
Above are the results for the second experiment. The semi-sweet and unsweetened
with all sodas stayed pretty consistence, white chocolate was not. For the white
chocolate, the numbers went from 35.5 degrees (sprite), 43 degrees (coke), 27.6
degrees (diet coke), and 44.2 degrees (water). Semi-sweet chocolate melted at 35
degrees (sprit), 37 degrees (coke), 37.8 degrees (diet coke), and 39.2 degrees (water).
Unsweetened chocolate melted at 38.1 degrees (sprite), 39.6 (coke), 38.9 (diet coke),
and 38.5 (water). For most of the chocolates diet coke was the liquid that caused the
chocolates to melt at the lowest temperature. The range of the different melting
temperatures is 16.6 degrees.

CONCLUSIONS

For the first the experiment the hypothesis was confirmed and correct, the unsweetened
chocolate melted at the lowest temperature. That could have been because
unsweetened chocolate did didn’t have as many ingredients and it easiest to cut.
Unsweetened chocolate melted at the lowest temperature (40 degrees), then white
chocolate (44.4), and at the highest temperature semi-sweet chocolate (45.5). This
experiment could be improved by having the same amount of chocolate and the hot
plates all be the same temperature when starting each trials. A future experiment for
this would be if the brand of chocolate determines the melting point, or if there is
something inside the chocolate (like a filling) will it make a difference.

For the second experiment the hypotheses was confirmed and not correct, half of it was
correct. Diet Coke was the liquid that made the chocolate melt at the lowest
temperature but the type of chocolate was white chocolate. The Diet Coke as the liquid
and white chocolate melted at 27.6 degrees Celsius. It was found that unlike semi-
sweet and unsweetened chocolate, the white chocolate’s number jumped around. The
range of the different temperatures that the white chocolate melts at was 16.6 degrees.
It could have been that the diet coke melted the white chocolate at the lowest
temperatures because it is diet and doesn’t have as much sugars, and or because it
wasn’t as bubbly as the other sodas. Overall this extension experiment did show that
the liquid under the beaker with the chocolate does make a difference.

REFERENCES

Béliveau, Richard, and Denis Gingras. Foods to fight cancer : essential foods to help
prevent cancer. New York: DK Publishing, 2007. Print.

"Chocolate." Compton's by Britannica. http://school.eb.com/comptons/article-9273650.

Encyclopædia Britannica Online School Edition.Encyclopedia Britannica, Inc., 2013. We
b. Jan. 17, 2013.

Ganeri, Anita. Indoor science. New York: Dillon Press, 1993. Print.

Hersey. “Ingredients.” http://www.hersheys.com/nutrition-

professionals/chocolate/composition/definitions/ingredients.aspx. Hersey. Web. Jan. 21,
2013.

Wikipedia. “Types of Chocolate”. http://en.wikipedia.org/wiki/Types_of_chocolate.

Wikipedia. Jan. 24, 2013. Web. Jan 21, 2013.