110 ml sucrose or 0.5 moles
1 ml NaCl (a small pinch, optional):
74 ml (3 M) glucose
48 ml H2O
hydrogenated vegetable oil
food coloring
flavors (see next column for suggestions)
The Effect of Temperature and Torsion on the Structure of Saccharide
(aka Taffy)
|
*FLAVORS
4-hydroxy-3methoxybenzaldehyde (vanilla)
3-ppmethanol (peppermint)
isoamyl acetate (banana)
methyl salicylate (wintergreen)
glycyrrhezec acid (licorice)
hesperidin (lemon)
This is directly from Mr. Ron Ulrich, my high school chemistry teacher. If the mere sight of chemical
formulae and words like "mole" (not the furry little critters) "torsion" and "reagents" sends you screaming
from the room, use this cooking term translation instead. This will make approximately 15-20 1" pieces,
which was plenty for two 16 year olds to have a tasty snack before holiday break., plus a few extra pieces to
take home to the family!
Place the first four reagents in the large beaker. Thoroughly mix with stirring rod.
Place over gentle to moderate flame until all the sucrose has dissolved, stirring constantly. Increase the
heat and do not stir during the rest of the heating. The stirring rod may be used to keep crystals from
forming on the sides of the beaker at the beginning of the experiment.
When the solution begins to boil, insert the thermometer (Don't let it touch the bottom of the beaker or you
will get the temperature of the hot beaker rather than the solution). Heat until the thermometer registers
270oF. While heating, prepare an aluminum foil pan and lubricate with hydrogenated vegetable oil. (The
pan is made out of aluminum foil by bending up the edges about 1" all the way around.) You will need 1 &
1/2 slices of margarine which you will be given already divided in 3 parts. One for the mixture after reaching
270oF (next step), one piece of margarine for the pan, and one part for you & your lab partners hands, when
you are ready to pull the taffy, NOT now.
As soon as the beaker reaches 270oF, remove the heat, and add one slice of hydrogenated vegetable oil
while stirring gently. The darkening of the mixture indicates the carbonization of some of the saccharide
molecules and this color should not get dark brown, as it then begins to taste burnt. Pour the mixture onto
the aluminum foil pan using the big beaker tongs. When the beaker is empty place the beaker in the hot
soapy water at your lab table along with the thermometer and stirring rod. (Start washing the beaker & other
materials NOW as taffy is cooling).
When the mixture is cool enough to touch the top, take approximately 1 ml of your favorite flavoring* and 3
drops of your desired color* (you may wish to bring your favorite from home) and sprinkle them across the
mixture. (Estimate the 1 ml- do not try to measure it.) Do not attempt to mix these last two reagents, as they
will become mixed as you pull the mixture.
Each team member should now lubricate their hands with the remaining hydrogenated vegetable oil. When
the mixture is cool enough to handle, begin to pull and fold, pull and fold. This allows the molecules to align
themselves and add air to the mixture.
When the mixture takes on a satin sheen, pull off bit-size pieces and wrap in saran wrap.
Options may be to build a candy cane. Your imagination may provide an interesting option to this
experiment. Consume the product.
Make sure your lab bench is just as you found it, thermometer and stir stick in the beaker, a new bag of
sucrose and one piece of Aluminum foil. All paper towels in the trash and the lab bench free of taffy, sugar,
etc. Carefully dump the wash water into your lab sink. Place the green scrub pads on the lab top near the
sink edge and take the pans to the back lab table