Rock Candy: What’s the Best Sugar? Susan Stewart-Craig and Jennifer Gremer DCC 330 May 16, 2013 1 Abstract We wanted to explore the process of making Rock Candy, specifically the type of sugar used. We wanted experiment with different sugars to see if the type of sugar made a difference in the size of the crystals in the rock candy. When we made our sugar and water solution, we substituted the type of sugar used. Then the solution was allowed to crystallize in a jar. The rock candy was photographed and measured using the ImageJ computer program. Our hypothesis was that the type of sugar used would make a difference in the size of the sugar crystals. More specifically we hypothesized organic cane sugar would work best compared to brown sugar and white sugar. We thought organic sugar would form the largest crystals because it is a direct source of sugar and the purist. However, our experiment proved our hypothesis incorrect. The white sugar formed the largest crystals. Organic sugar made very tiny crystals and brown sugar never crystallized. Introduction Sugar is a carbohydrate composed of hydrogen, hydrogen, and oxygen molecules. The two main types of sugars are monosaccharides and disaccharides. Sugar comes from two plant sources: sugar cane and sugar beets. Organic cane sugar is harvested and milled on the same day from certified organic sugar cane. White sugar is cane sugar that has been furthered processed. Brown sugar is white sugar combined with molasses. The purpose of the experiment was to determine if the type of sugar used in making rock candy affected the size of the sugar crystals. Our objectives were to learn about different types of sugars and determine the effects different types of sugar have on recyrstallization that occurs when making rock candy. We dissolved together sugar and water, cooled, placed in a jar with a 2 seed, and then allowed to crystallize. Our hypothesis was that organic cane sugar would form the biggest crystals compared to brown sugar and white sugar. Methods Our study was conducted in Gordon Hall Kitchen and Room 1224, SUNY Brockport, Monroe County, New York. This study took place from April 23, 2013 to May 7, 2013. When creating rock candy you must have a lot of time on your hands because it is a timely process. First you must find the right type of glass container that will hold your sugar and water solution. For our trials we used Ball pint size glass jars. You then, must measure and cut the material that you will use for your “seed”. In our research we came across some studies where people used wooden Popsicle sticks, bamboo skewers, and string. In our trials we decide to use string. You must cut your material long enough to be submerged into the solution but short enough where they do not touch the bottom of the container or the candy will form on the bottom and connect to the string, not forming a free structure of crystals. After cutting our strings to the right sizes you must wet the strings and roll them in the sugar that they will be submerged in. We used three different types of sugar Great Value Pure Cane White Sugar, Great Value Light Brown Sugar, and Domino Pure Cane Sugar. We did three tests for each brand of sugar so in total we had nine “seeds”. We let them dry for two days, just to make sure the sugar would stay on the strings. To make sure each string was in the middle of the jar, we taped them to Popsicle sticks that we later taped to the jars so none of them would move. We left them out of the jars at this point, which will be explained shortly. We then made the sugar solution for each brand of sugar by boiling water and slowly stirring in measured amounts of sugar, using a 2:1 ratio, two cups of sugar for every one cup of water. We then put one cup of the solution in each 3 jar, and waited 20 minutes for the solution to cool down. You must do this or the sugar will melt off of the string and the candy will not form on the string but rather the bottom of the jar. We then let the candy set for two weeks; it was in the shade and in a relatively dry area so this time will vary for each experiment. Each sugar was different in the way that it formed, or lack of formation. Results The sugar that produced the largest crystals was white sugar. The average area of the white sugar rock candy was 15.654 cm squared (Table 1). Organic cane sugar had the second largest average area which was 8.618 cm squared (Table 1). Brown sugar came in last with an average area of 1.5 cm squared (Table 1); however, brown sugar never crystallized so this is the area of the seed string. The seed string upon which the sugar crystals grew was included in all of the area measurements. Table 1. Anova Single Factor Statistically Test SUMMARY Groups Count Sum Average Variance White Sugar 3 15.654 5.218 0.813313 Brown Sugar 3 4.5 1.5 0 Cane Sugar 3 8.618 2.8726666 0.78679 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 21.208326 2 10.604163 19.88152 0.002254 5.1432528 Within Groups 3.2002066 6 0.5333677 Total 24.408532 8 4 Area Trial 1 Trial 2 Trial 3 White Sugar 4.259 6.049 5.346 Brown Sugar 1.5 1.5 1.5 Organic Cane Sugar 3.873 2.182 2.563 Table 2. Area of sugar crystals in cm squared after 14 days. White sugar formed the largest sugar crystals during the experiment. The white sugar solution was allowed to sit for 2 weeks during a trial in order to crystallize. The area of the white sugar crystals including the seed string were taken on the last day (day 14). Trial 1 had an area of 4.259 cm squared (Table 2). Trial 2 had an area of 6.049 cm squared (Table 2). Trial 3 had an area of 5.346 cm squared (Table 2). Organic cane sugar formed the second largest sugar crystals. The organic cane sugar was allowed to sit for 2 weeks during a trial in order to crystallize. The area of the organic cane sugar crystals including the seed string were taken on the last day (day 14). Trial 1 had an area of 3.873 cm squared (Table 2). Trial 2 had an area of 2.182 cm squared (Table 2). Trial 3 had an area of 2.563 cm squared (Table 2). Brown sugar did not form any sugar crystals. The brown sugar was allowed to sit for 2 weeks during a trial in order to crystallize. The area of the brown sugar crystals including the seed string were taken on the last day (day 14). Trial 1 had an area of 1.5 cm squared (Table 2). Trial 2 had an area of 1.5 cm squared (Table 2). Trial 3 had an area of 1.5 cm squared (Table 2). The area of the brown sugar trial is strictly the area of the seed string. The area of the sugar crystals for the same type of sugar during each trial was compared. All 3 trials of white sugar were compared (Figure 1). All 3 trials of brown sugar were compared 5 (Figure 2). All 3 trials of organic cane sugar were compared (Figure 3). This shows that all the trials formed approximately the same size crystals each time that sugar was used. White Sugar 7 6 5 4 3 Area in cmin Area 2 1 0 Trial 1 Trial 2 Trial 3 Trial Figure 1. Area of white sugar crystals with the seed string in cm squared after the 3 trials. 6 Brown Sugar 1.6 1.4 1.2 1 0.8 Area in cmin Area 0.6 0.4 0.2 0 Trial 1 Trial 2 Trial 3 Trial Figure 2. Area of brown sugar crystals with seed string in cm squared after the 3 trials. Organic Cane Sugar 4.5 4 3.5 3 2.5 2 Area in cmin Area 1.5 1 0.5 0 Trial 1 Trial 2 Trial 3 Trial Figure 3. Area of organic cane sugar crystals with the seed string in cm squared after the 3 trials. 7 Types of Sugar Comparison 7 6 5 4 White Sugar 3 Area in cmin Area Brown Sugar 2 Cane Sugar 1 0 Trial 1 Trial 2 Trial 3 Trial Figure 4. Comparison graph of the area of sugar crystals and seed string in cm squared for the 3 trials. An analysis of variance test was performed using Microsoft Excel. The analysis of variance gave us a p-value which helps determine if the numbers are significantly different or not. The p-value is 0.00254. Because the p-value for this data set is < 0.5 there is a significant difference. The area of the rock candy significantly differed based on the type of sugar. Discussion Our hypothesis was proved incorrect. Organic cane sugar did not produce the largest crystals. White sugar produced the largest crystals. Our initial thought was that the sugars might need different amounts of times to crystallize and that what was affecting the size of the crystals. The rate of crystallization is the speed at which nuclei grow into crystals.