Doc, are you sure that Corn Sugar, corn syrup and Maltodextrin are the same thing? I thought Corn Sugar is dextrose and corn syrup is glucose?
I e-mailed John Palmer from howtobrew.com about this a while ago (last year, i think), and this was his response:
Hi Steve,
Thank you! Glad to here it. Hopefully ESB Brewing Supplies in Sydney
will start carrying my book in their store sometime this year. If we
can figure out how to get it there...
Hmmm, this is a tough one, one because I am not sure everyone (country)
is using the same terminology, especially in the supermarkets.
The "corn sugar" that Americans talk about for priming is indeed
Dextrose, which is actually glucose of a particular chemical structure.
Maltodextrin powder is not fermentable, being composed of unfermentable
heavy sugars (polysaccarides). Fructose is a slightly different kind of
sugar that tastes sweeter than sucrose (cane table sugar). So when you
see Corn Syrup (ie. high-fructose corn syrup) at the store, you can use
it for priming. It is 99% fermentable, compared to sucrose and glucose,
but the key is that it contains 1% unfermentable sugars, AND WATER. You
need to know how much water is in the syrup to know how much priming
power it has. Try using a hydrometer and perhaps diluting with a known
amount of water if it is too thick to give a good reading.
So, to summarize: Maltodextrin powder is composed of unfermentable
dextrins (polysacc.s) and is not dextrose. Dextrose is glucose. (This
is equivalent to saying that women are human beings, but not all humans
are women.) I could extend this metaphor to fructose (invert sugar),
but I think you get the idea. ;-)
Let me know if you have any more questions,
John