I was driving and Mark was telling me about a conversation he had with a co-worker at the Giant Multinational Food Processing Company, a discussion about making marshmallows at home. He had just finished telling me that it is indeed possible to make mini marshmallows that look a bit like extruded ones, and was telling me something else about the process:
"...so, you know, you take your sugar and your corn syrup and you mix it with water and heat it gently until the sugar dissolves, and then you start to boil it--"
"Yes, so you've got your candy thermometer in it," I said, nodding and thinking of all the recipes I've read about making candy.
" Yes, so, you boil it to drive off the water while you're monitoring the rise in boiling point temperature with your candy thermometer --"
My mouth fell open. "Oh my gosh. I am such a dolt."
"Uh -- why?"
"You're using the candy thermometer to monitor the boiling point temperature? As a proxy for sugar concentration?"
"Well -- yeah --"
"Because it's the sugar concentration that controls the properties of the candy. I AM A DUMMY."
"...?.."
"Mark! I have known for years that you need a candy thermometer to make candy, and that you cook sugar syrup to a precise temperature, like two hundred thirty-seven degrees or something, and then that you have to finish the cooking really quick and make the stupid candy. "
"Yes, and?"
"I am thirty-four years old and I have two degrees in chemical engineering, AND NOT UNTIL THIS MOMENT did I realize WHY the temperature mattered . All this time it's been colligative properties, and I thought it was, you know---"
"Cooking."
"Yeah. Cooking."
Well, boys and girls, can you say "compartmentalized knowledge"?
I knew you could.
Seriously, though, good post.
Posted by: Bernard Brandt | 26 October 2008 at 09:47 PM
Ah, yes. Colligative properties. Being a ChemE myself (and not much of a candy maker) I have to admit that this had never occurred to me either.
Posted by: mary | 27 October 2008 at 08:54 PM