Mr. Obvious wrote:
You can read the article for a better explanation but basically the sugar breaks down into component parts when it is heated. The end result is not sucrose any more.
\
Gotcha. It's chemical transformation (where the catalyst is heat) as opposed to melting which is just a state change (solid to liquid). Thanks.
ah.... wrote:
Mr. Obvious wrote:You can read the article for a better explanation but basically the sugar breaks down into component parts when it is heated. The end result is not sucrose any more.
Gotcha. It's chemical transformation (where the catalyst is heat) as opposed to melting which is just a state change (solid to liquid). Thanks.
Oh, my! Thank you helping me understand my observations! I was so perplexed.
sadfsadf wrote:
What are you talking about? Sucrose is an exact substance. By definition! It has a specific atomic structure and any deviation from that is NOT sucrose anymore!
it may be that cane sugar from different sources has differing amounts of sucrose and other chemicals IN THE EXTRACT which is sold as "cane sugar." And that could affect the melting point slightly. But the rate of heating has no effect on melting point.
Sheesh. Some people need to learn some high school chemistry.
Double sheesh. Clearly you failed high school chem.
Does this phenomenon explain why I screwed up the caramel I made over Christmas? Please say yes.
dean moriarty wrote:
Does this phenomenon explain why I screwed up the caramel I made over Christmas? Please say yes.
Possibly. Did you heat it up quickly? I always take my time when cooking sugar-based foods. Long, low and slow is key otherwise the sugar will burn and the food will taste bitter not sweet.
malmo wrote:
sadfsadf wrote:What are you talking about? Sucrose is an exact substance. By definition! It has a specific atomic structure and any deviation from that is NOT sucrose anymore!
it may be that cane sugar from different sources has differing amounts of sucrose and other chemicals IN THE EXTRACT which is sold as "cane sugar." And that could affect the melting point slightly. But the rate of heating has no effect on melting point.
Sheesh. Some people need to learn some high school chemistry.
Double sheesh. Clearly you failed high school chem.
Glucose + fructose = sucrose. Sucrose just a glycolic linkage between glucose and fructose but fructose itself can be found alone in natural sugar. Different sugar sources or different refinements of sugar will result in different ratios of glucose to fructose and this may be why you would see a range of melting point values. Fructose has an actual melting point (103 C) while sucrose decomposes while melting which further complicates the melting point determination. Typically mixtures of two or more molecules (non-pure substance) will tend to give broad ranges of melting points. This is without regard to other non-sugar molecules potentially being in homogeneous mixture with your fructose/sucrose "sugar."
Opiate for the Masses wrote:
Fructose has an actual melting point (103 C) while sucrose decomposes while melting which further complicates the melting point determination. Typically mixtures of two or more molecules (non-pure substance) will tend to give broad ranges of melting points. This is without regard to other non-sugar molecules potentially being in homogeneous mixture with your fructose/sucrose "sugar."
The link indicated that fructose also decomposes although it appeared that was still not fully researched (or ready for publication or something).
All of this just reinforces my conviction that physics is the only science where the researchers are capable of discovering anything.
Chemists seriously haven't figured out the melting of sugar? What a bunch of novices.
Or, possibly, it's well understood and we on letsrun just haven't gotten the memo.
physics fan wrote:Chemists seriously haven't figured out the melting of sugar? What a bunch of novices.
Yeah- it should be obvious to chemists given the fact that melted sugar can't be melted over and over again without dramatic changes in its molecular structure and chemical composition. Obviously it is being broken down during the "apparent melting" process even at very low temperatures.
In comparison, glass can be melted multiple times without any decomposition or change in its molecular structure.
Thanks. I must have, because it did come out tasting bitter. It was a bummer. Next time I cook with sugar, I'll pump this jam:
physics fan wrote:
All of this just reinforces my conviction that physics is the only science where the researchers are capable of discovering anything.
Chemists seriously haven't figured out the melting of sugar? What a bunch of novices.
Or, possibly, it's well understood and we on letsrun just haven't gotten the memo.
Or it could be that the crystal structure of sugar is stronger than the glycolic linkage between the two sugar sources and thus you get decomposition before melting. I don't understand how this is so confusing: some things decompose or react at lower temperatures (break chemical bonds) before their crystal structures break down.
The physicists I know don't take cheap shots at us chemists. You must not be a physicist or if you are, you're a pretty poor one.
Just about anything has a specific melting point. If the OP brought his sample of sugar to a lab, they could identify it for him.
When samples are contaminated or conditions vary, you may not get the exact properties published in the literature. All that tells you is that your sample is contaminated or conditions don't match the "standard" conditions. It doesn't mean there is no specific melting point.