From sugar to brittle and back?

I tried to make almond brittle using maple syrup instead of corn syrup - I ended up making maple tasting sugar crystals... what did I do wrong in hindsight?

           From this to this!

Normally in making brittle type candies it seems all you need to do is to melt sugar and create a liquid that then hardens like a glass.  Here is an example from Allrecipes.com.

Mom's best Peanut Brittle

Ingredients:
1 cup white sugar
1/2 cup light corn syrup
1/4 teaspoon salt
1/4 cup water
1 cup peanuts
2 tablespoons butter, softened
1 teaspoon baking soda

Directions:

1. Grease a large cookie sheet. Set aside. [or you can use parchment paper instead]
2. In a heavy 2 quart saucepan, over medium hear, bring to a boil sugar, corn syrup, salt and water. Stir until sugar is dissolved. Stir in peanuts. Set candy thermometer in place and continue stirring. Stir frequently until the temperature reaches 300 degrees F (150 degrees C), or until a small amount of mixture dropped into very cold water separates into hard and brittle threads.
3. Remove from heat;  immediately stir in butter and baking soda; pour at once onto cookie sheet. with 2 forks, lift and pull peanut mixture into  rectangle about 14x12 inches; cool. Snap candy into pieces.

All rights reserved copyright 2010 Allrecipes.com

This recipe works beautifully so why did my simple substitution of the maple syrup end up crystallizing instead of staying glassy?



Turns out that corn syrup and maple syrup are actually quite different not only in taste.  Corn syrup is mainly glucose and maple syrup is mainly sucrose (as is plain white sugar)  The addition of the corn syrup to the brittle recipe is to interrupt the reformation of sugar crystals at the high temperatures when the mixture is supersaturated. We want the supersaturation to create the glassy liquid but, in a pure sucrose mixture at high heat, any crystal that is in the pot can create a rapid crystallization of the whole mixture which is what happened in my case!


As I researched a bit more I discovered that most brittle recipes that use maple syrup also add some butter at the beginning as this will also help prevent the crystallization from occurring by keeping the sugar molecules separated by minute amounts of oil.



So I redid my experiment: I took the recrystallized sugars, blended them until they were small crystals again and remelted them - this time with 2 tablespoons of butter added immediately.  Panic set in at the 250 degree mark as it looked like it was going to crystallize again (Sidenote: Use a silicon or very sooth spatula to stir; not a wooden spoon as there are many more crystallization sites on a rough surface!) but I kept stirring and finally it stayed melted at about 300 degrees (hard crack).  I added some roasted almonds and poured the mixture onto a baking tray covered in parchment paper. The colour was much darker since it had been double-heated but it tastes yummy!

Here is a proper maple sugar brittle recipe

Maple Walnut Brittle

1/4 cup real maple syrup
1 cup granulated sugar
1 cup butter
1/4 cup water
2 cups toasted walnut pieces

In heavy bottomed saucepan, over medium heat, stir together syrup, sugar, butter and water until melted and creamy. Continue to gently boil and do not stir until candy thermometer reaches 300°F (150°) “hard crack”. Immediately stir in walnuts and carefully pour hot mixture onto an ungreased cookie sheet and spread out to a thin layer with a wooden spoon. Cool completely.

Break into large pieces and store in an airtight container. 

Makes 1 pound.

Recipe provided courtesy of the American Heart Association.

Added references
For more maple sugar info:
Maple fact sheet 202
Ochef - Using Sugar, Brown Sugar, Honey, & Maple Syrup Interchangeably
And a quick scientific overview of how the sugars differ in making candy:
http://www.exploratorium.edu/cooking/candy/sugar.html