A bazillion years ago, a friend and I took a candy making class. They told us that they use cane, not beet, sugar to make candy because when you cook (boil) beet sugar, it boils up much higher in the pan than cane sugar. More likely to boil over.
Why is this? Is this even true?
Snowangel: I didn't test this specifically. However, I did test making caramel on the stovetop. This is why I like these follow-up sessions. I can throw in a few things I learned that didn't really fit.
I didn't include the test because:
1) It was much harder to ensure identical conditions -- the heat of the pan, the color of the sugar as it caramelized, the distribution of sugar in the pan, the temperature and humidity of the environment -- all of these contributed to what I felt were inadequate circumstances for reporting purposes; all of these defects were resolved by the setup for broiling;
2) The results appeared to be the same as for the broiled caramel;
3) The article was running too long already.
I put 200 grams of sugar and 4 fluid ounces of water in a stainless steel saucier and applied medium heat. I stirred very gently until the sugar dissolved, then left it alone until the mixture turned a medium brown. The timing for each type of sugar was virtually identical.
I did not note any foaming action. This doesn't mean it didn't happen, only that I didn't note it, because it wasn't on my list of things to watch. However:
-- I feel certain that had one type of sugar behaved in any significantly different manner, I would have made notes to that effect.
-- The mixture was approximately 12 ounces (by volume) in a 3-quart pan; in other words, the space was only about 12% occupied, and in no danger of boiling up. This might not be conducive to creating the situation you describe. In candy-making, I think you would use more of the pan, if you follow me, and the situation, if it were to occur, would be riskier.
It's pretty hard to find out what makes up the last 0.05% of refined white sugar, especially if you want to know how it might vary according to source. But what I did find out was that the largest component is ash (left over from the refining process), followed by potassium, sodium and a litany of elements in extremely minute quantities. This is always expressed without reference to beet or cane sugar. It could be that analysis of sugar regardless of source renders the same results, or that these are composite results. I just don't know.
Ash is inert. In combination with certain other elements, potassium and sodium can precipitate or participate in chemical reactions, but they are present in such small amounts that it's hard (though not impossible) to believe that they would lead to big differences in the way beet and cane sugar behave in the presence of heat.
I haven't made a study of candy making; I don't make candy even for fun. But I did look at the candy sections of the cookbooks in my collection, and not a one mentions a difference between cane and beet sugar. I find this significant.
The most likely cause of boiling up would be moisture. Certainly if you are using brown sugar this could happen, at least until the water had evaporated (though the moisture content even in brown sugar is rather small). But the difference would not relate to cane or beet source, it would relate to the moisture in the molasses that is added to white sugar to make it brown. White sugar is extremely dry. This is why, among all the refined vegetable products in your pantry (corn flour and meal, all types of wheat flour, pasta, cereals, etc.), sugar has by far the longest shelf life, and is least amenable to supporting insect colonies.
Finally, I would suggest that you try it yourself and see what happens. You shouldn't take my word for it, or the word of anybody else, especially when you have the means to test it. Then let us know.