Corn syrup, also known as glucose syrup to confectioners, is used in foods to soften texture, add volume, prevent crystallization of sugar, and enhance flavor. Corn syrup is distinct from high-fructose corn syrup (HFCS), which is manufactured from corn syrup by converting a large proportion of its glucose into fructose using the enzyme D-xylose isomerase, thus producing a sweeter compound due to higher levels of fructose.
Fructose is sweeter than sucrose, which is sweeter than glucose.
It is surprisingly difficult to buy high-fructose corn syrup in non-industrial quantities. I looked into it as a homebrewer, figuring it’d be the cheapest sugar to ferment into alcohol in the US (corn subsidies), and the smallest amounts I could find were ~5 gallons, and finding even that took an amount of digging that left me uneasy.
I’ve since discovered cheaper fermentables: expired molasses can sometimes be had for free and, though I haven’t worked through the practical details, agricultural waste ought to work too given the existence of fuel ethanol.
If you search for “high-fructose corn syrup” on Amazon, you’ll get anything but high-fructose corn syrup. Wild.