Friday, January 26, 2018

Organic Chemistry: Candy Making

This is my science club for my oldest students... my own teenage daughters and one of their friends. We began by reviewing the fact that plants use the process of Photosynthesis to make their own food (sugar). We read all of "The History of Sugar" in David Mitchell's book (page 141), which explains how we get sugar from sugar cane and sugar beets. Then the girls shared with each other what they knew about tapping sugar maples to make maple syrup. My daughters have had the finished homemade maple syrup from trees their father tapped, but were not there while it was being made; their friend went to a local Maple Syrup Festival and saw the taps and tasted the sap. I passed around pure maple syrup as well as maple sugar for tasting.

Then we watched a YouTube video (8:39) of Jaggery (brown sugar) production from palm trees. Here is the accompanying description:

    Sweet sap or Toddy is harvested from Palmyra palm trees and processed on the same day to yield country sugar or jaggery or palm sugar. This is used as a natural sweetener. The tree is common to India, Srilanka and south-east Asia. It grows in the wild from Persian gulf to Cambodia. The Asian Palmyra Palm (tnaƓt) is the national tree and a heritage symbol of Cambodia. It grows Near the Angkor Wat Temple. Palmyra Palm is also common in Thailand, especially in the north-east or Isaan provinces.

    During the toddy season from January to June, the inflorescence of female palm trees (cluster of tiny immature fruits) is tapped and the sweet sap is collected every 24 hours. (If the inflorescence is left untouched, they will grow into clusters of palm fruits, the sweet pulp of which is also eaten. The male trees' inflorescence is not edible at any stage. But male trees are essential for pollination). The sweet sap is also consumed as a natural sweet drink. If the harvesting pot's interior surface is not coated with lime, then an alcoholic drink (palm liquor that is sour in taste) results due to fermentation. The sweet sap is heated and the concentrate is poured into wooden cast and left to solidify into palm sugar blocks. The word 'Jaggery' is derived from Sugar. Jaggery is brown in colour.

I found some canned toddy palm seed at the International Grocery Store so we tasted it. None of my students had ever had it before! We also tasted other natural sweeteners: date sugar, coconut nectar, and agave nectar.

After our plethora of snacks, the girls relaxed while I read them "A Tight Squeeze" from What Einstein Told His Cook: Kitchen Science Explained. This book was recommended in the recent blog at The Parenting Passageway on Seventh and Eighth Grade Chemistry. Check it out. It's a GREAT post!

I drew a diagram on the chalkboard of the latticework shape of water molecules, with the sugar molecules tucking into the empty space. Robert Wolke mentions candy making in his explanation, which was a perfect transition into our next activity. I explained the stages of candy making, using Leah's old MLB for Measurement and Baking. She made a beautiful chart listing the stages, percentage of sugar, and temperature of each.

I got out my grandmother's vintage candy thermometer (the one remaining of the two she left when I inherited this kitchen) and showed it to the students and we compared its design alongside a meat thermometer. They drew the candy thermometer in their notes while I read them my blog posts describing -- in great detail -- the first (unsuccessful) time and the second (successful) time Leah and I tried to do this activity together. This helped them know exactly what to expect.

Then, it was into the kitchen and time to get started! We didn't try a recipe today. This was simply so they could experience the stages, pouring a little bit of the sugar syrup into a mixing bowl full of cold water and ice and seeing how the results changed over time as the syrup passed through the stages.

In our small saucepan -- starting with 1 cup sugar and 1/2 cup water -- it took from 5:22 pm to 5:57 pm to get to something really exciting (the "tink" of soft crack). They loved how the sugar was forming beautiful sculputures in the cold water. They were to hard crack stage and done by 6:04 pm.

our small bowl of cold water and ice
and the syrup-covered ladle from repeated experimenting

P.S. Happily, in looking up the 2018 date for the Maple Syrup Festival, we learned that it is coming up soon! February 24-25, 2018 from 9 A.M.- 3 P.M.

This post contains affiliate links to the materials I actually use for homeschooling. I hope you find them helpful. Thank you for your support!

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