I realize that I never posted about my trip to Martinique over a month ago. On Martinique, like many Caribbean islands, European settlers first planted tobacco, then switched to sugarcane when the market collapsed. On Martinique the sugar market also collapsed, so Homere Clement and other sugar producers turned their giant sugar factories into giant rum distilleries. They just skipped the middle step of making granular sugar.
Rum distilled from sugar cane juice instead of molasses on Martinique is called rhum agricole (they refer to other rums as "industrial"). The agricole distilleries take in sugarcane, smash it and shred it to get all the juice out, then ferment the juice and distill it into rhum. The leftover cane fibers are burned to generate steam, which in turn powers the distilleries. The steam engines are enormous machines at the front and center of each agricole distillery, which makes them some of the coolest to visit- they're loud with big spinning parts. Here's a video I took in Martinique:
The Modern Marvels video didn't touch on rhum agricole, but did mention sugar production in other areas. Hawaii produces a large amount of sugar from cane, but as far as I know no brands of American cane sugar rum are on the market. In Brazil, not only do they make cachaca from sugar cane, they fuel their cars with the distillate.
Something like 40% (I could be wrong on the number) of sugar now comes from sugar beets from colder climates instead of sugar cane from the tropics. But according to this discussion on the Ministry of Rum website, sugar beet molasses is high in salt and doesn't produce good spirit.
A lot of the sweetener used in the US since the 1980's is from corn, in the form of high-fructose corn syrup (HFCS). I think that with the corn ethanol poor government planning and HFCS/obesity epidemic bad press, the (mostly corn-based) bourbon industry had better start using organic corn if they're going to come out of this retaining their "traditional American heritage" image.
But corn is a different story. For that, you can watch the documentary King Corn, or the History Channel also has a Modern Marvels on that crop.