From: Karen Mendelow Nelson (karenm@exploratorium.edu)
Date: Tue Dec 03 2002 - 11:30:21 PST
Message-Id: <l03130305ba12b477085f@[192.174.3.212]> Date: Tue, 3 Dec 2002 11:30:21 -0800 From: Karen Mendelow Nelson <karenm@exploratorium.edu> Subject: judy Keeve's Famous Fudge
for your Holiday and Chemistry of Food pleasure - and the person who
requested the fudge recipe on pinhole
Judy Keeve's Famous Fudge
2 cups sugar
11 marshmallows
1 small can of evaporated milk
1 6oz package of semi sweet chocolate chips
1 cube of butter
1 cup of nuts (if desired)
Bring first three ingredients to a rolling boil and then boil for 6 minutes.
Pour into a bowl containing chocolate and butter and beat until everything
is completely melted and combined.
Let cool somewhat, and add the nuts.
Pour onto oiled surface (plates or aluminum foil) and allow to cool completely.
This recipe can be doubled if you wish, and freezes well.
Sucrose Crystallization and Judy Keeve's Famous Fudge
While making fudge,
Keep stirring constantly during the whole process.
Look at sugar crystals under the microscope.
Measure temperature at beginning.
Measure temperature at boiling.
Measure temperature after 6 minutes of boiling.
Try a drop of solution in cold water during stages of boiling.
Notes on sugar crystallization:
Sucrose = glucose + fructose
o Identical sugar molecules tend to stack together in a regular pattern to
form a solid crystal.
o Heating causes sugar to melt into a clear liquid, disrupting the
crystalline structure.
o While heating, some fragments evaporate producing a caramel smell. Some
fragments are trapped in liquid forming a darker mixture. If the mixture
is heated too much it will burn.
o When boiling, water evaporates and sugar concentration increases.
o Higher concentration, higher boiling temperature
o Concentration of sugar can be determined with the candy thermometer
o at 70% sugar, boiling temperature ª 230ƒF, a drop in cold water is threadlike
o at 80% sugar, boiling temperature ª 240ƒF, a drop in cold water is a soft
ball
o at 90% sugar, boiling temperature ª 255ƒF, a drop in cold water is a hard
ball
o at 98% sugar, boiling temperature ª 300ƒF, a drop in cold water is a
cracked hard ball
Making fudge crystals
The goal of a soft creamy silky crystalline candy, like fudge, is to create
very small crystals. When the fudge is beaten, as it nears room
temperature, and is extremely supersaturated, stirring encourages crystal
formation and breaks up large crystals into smaller fine crystals.
Karen Mendelow Nelson
Program Manager and Science Educator
Exploratorium Teacher Institute
3601 Lyon Street
San Francisco, CA 94123
karenm@exploratorium.edu
415-561-0313
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