I was wanting to do something cool for the science with cooking contest. At first, I was wanting to get some dry ice or liquid nitrogen, but I thought heat would be the way to go. I have made candy apples and sugar glass a couple of times and I thought I could make prince Rupert drops with a sugar glass recipe. As with a lot of science experiments, the results are sometimes best when they are something that you do not expect. I ended up unsuccessful at making prince Rupert drops, but the results were some beautiful sugar glass strands.
Step 1: WARNING!
As with just about all my instructables; this can be hazardous to your health. In this experiment, we will be working with a sticky molten sugar solution at temperatures in excess of boiling. If you are not careful, you can get some very nasty burns. At the least, I suggest safety glasses and gloves.
Step 2: Supplies and Ingredients
The supplies I used were:
(1) 1/2 gallon glass jar (The first failed experiment I tried one jar filled with ice cold water and the other with just cool water. l found that the cool water worked best and that is what I used in the second experiment)
(1) Stainless steel pot (I was worried that the pot would need to be scrubbed and could possibly be ruined, but a good soak in warm water does wonders to clean up the sticky mess)
(1) Source of heat that can get your mixture up to 300 degrees Fahrenheit. I used a camp stove, because I was doing this outside to avoid a mess inside.
(1) Sheet of parchment paper or wax paper. (to make clean up easier)
(1) Candy thermometer or something that can accurately measure the temperature of the solution up to 300 degrees Fahrenheit.
(1) Spoon to stir the solution and to spoon out drops into the water.
The ingredients needed are:
(2) Cups of white sugar
(2/3) Cup water
(2/3) Cup corn syrup
(1/4) Teaspoon cream of tartar (not a cream but a powder, the name is strange)
An optional but fun ingredient is some food color.
Step 3: Mix
Gently mix the sugar, water, corn syrup, and cream of tartar in the pot.
Step 4: Slowly Heat It Up
Put the pot over a medium heat. The goal is to boil off the water and bring the mixture to a hard crack temperature of about 300 degrees Fahrenheit. Make sure your candy thermometer is in the solution but not touching the bottom of the pot. It will seam like it is taking forever to get to heat up, but when the water boils off the temperature will climb rapidly. If it gets too hot, your sugar solution will burn and be a horrible looking mess that will taste like burning.
Step 5: Spoon Out the Solution to Test the Temperature
One way to test if the solution is at the hard crack stage is to spoon out some and drop it into the cool water. If it only cools and feels soft, it is at the soft crack stage. If it cools and is hard and brittle, it is at the hard crack stage. Remove it from the source of heat and start dribbling it into the water. The faster you dribble it, the larger the strands will be.
Step 6: Add Food Color
If you want to, try adding food color. You will want to work quickly, or the solution will cool down below the hard crack stage.
Step 7: What I Have Learned
The first time I tried this I did not have enough solution. I had halved the recipe to fit my pot. This was a mistake because the solution was so small that the temperature climbed too rapidly from the soft crack to the hard crack and ended up burnt and nasty. By doubling the amount, I was better able to control the climb in temperature and get great results. I did not get the prince Rupert drops that I originally wanted but the strands turned out beautiful and were a lot of fun to make. I also learned that soaking the pot, spoon, and thermometer in warm water made cleaning up easier than I expected it to be.
As always, Thank you for viewing and I hope you enjoy.
Second Prize in the
Science of Cooking