I made Turkish Delight today. I used 2 large cups sugar, 1oz gelatine, 1 saltspoon citric acid and 1cup boiling water. Boiled all together for 15 minutes then halfed the mixture. Flavoured one with lemon essence and coloured lemon and the other half flavoured with rosewater and tinted pink. Allowed it to set. Lemon is almost perfect texture but the rosewater one is "grainy" and much firmer set than the lemon. Why is it so? It was the same mixture, halved!
Grainy means your sugar formed crystals during the heating process. Lemon and other acids retard the formation of crystals, which is why one came out better than the other.
I'd suggest adding some cream of tartar to the other one (which should do the same as the lemon, but without changing the flavor).
In general, to lower crystallization, you should make sure the pots are absolutely clean, and then take great care not to stir or jostle the mix during the heating process. You can also add a little corn syrup, if you roll that way (adding acid actually inverts some of the sucrose into glucose and fructose, which is why it helps to add acid, but you can also just add glucose, in the form of corn syrup. I wouldn't use honey, because of it's water content.)
Hope that helps.