Hi,
old discussion, I know, but someone could be interested in how the real story is, a part of it at least
I did extesive reaseaches for understanding what ligth candy sugar is and what are the differencies with inverted sugar (if there are any differencies, I suspect it is a blend of inverted and table sugar). I met some goals about the process and find many hints about the process for producing the dark one.
Only problem: it is in Italian...
http://www.movimentobirra.it/public/file-caricati/MOBI_01-2013.pdf (pag. 9)
Briefly: some of you said right things. But you missed one point, I think: you cannot have ANY Maillard reaction with sucrose. That's why you have to invert table sugar to have the Maillard reaction, it works with fructose and glucose, not with sucrose. You can only caramellize sucrose. AFTER you inverted the sugar, you increase pH adding some amino acids to help the Maillard reaction, the easy way is adding ammonium bicarbonate. Under 140 C you will mainly have Maillard reaction and less Caramelization (it works above 100 C). You can play with time and temperatures to develop a good profile for you dark sugar. In my article you can find some indications about level of pH where the two reactions could be achieved (2.5-3 and 4-4.5)
Regarding the possibiliy to invert sugar during the boiling, what Denny says is not correct. Look at this graph:
http://bressanini-lescienze.blogautore.espresso.repubblica.it/2008/11/19/che-cos%E2%80%99e-lo-zucchero-invertito/
This is the time, temperature and pH needed to invert HALF of the sugar. So putting your sugar at the start of the boil you will need 2-3 hours to invert HALF of it (and it will be darker, not optimal for a Tripel)
I do not know if there are some differencies in the flavour profile between plain and inverted (ligth) sugar: some brewers use the plain, others use the inverted, and other use the candy ligth (in Europe, for breweries, there are both the inverted and the candy). A friend of mine, brewer and great taster, said that with blind tasting candy ligth resulted better than the inverted. Anyway, in homebrewing, I use sugar inverted on my own: it is not a great effort, add citric acid, add sugar, warm up a pot, wait until it gets cold, add ammonium bicarbonate (or baking soda, it works the same for ligth candy) and that's it