I've been reading about making some Belgian Candi Sugar for a Piraat (Belgian Tripel) recipe I want to make and finding some inconsistencies about the techniques. People talk about using citric acid and this is backed up in this Inverted_sugar_syrup article and says cream of tartar is fine as well. I found mention that if you want clear BCS then just drop table sugar in the boil kettle and that heat will do the conversion... BUT the lowest temperature I've seen listed for triggering the conversion is 240°F (115°C) which won't be achievable. Stove top cooked sugar can reach these high temps though.
So I found the-how-to-for-making-belgian-candi-sugar.219960 which leads to a PDF published by Beer Brewing Radio which states using Diammonium Phosphate which when I search online is described as a fertiliser but also is used as a Yeast Nutrient. Reading about it as a fertiliser I can see that there's an increase in pH over time, but how does it compare with the acidic levels of Citric acid or cream of tartar.
Can anyone say definitively which one I should use? I have cream of tartar in the pantry, but I'm not sure how much to use, the Beer Brewing Radio PDF says to use 1/2 tsp of DAP with 1 cup water and 2 lbs sugar, but how much cream of tartar of citric acid does that translate to? Is it worth just buy some Yeast Nutrient and follow this recipe to the letter?