The ice cream is granular in texture-
I actually own the same ice cream maker, and it has made some very good ice cream for me. The most likely causes of grainy ice cream are too short of a time in the machine or recipes with incorrect proportions of water, fat, and sugar.
Firstly, make sure that you are using one of the recipes provided in the maker's user manual, or a different recipe from another source which says that it works with all ice cream makers. Following these recipes will ensure that your ice cream base (the liquid that you pour into the machine) is the correct consistency and composition for freezing. For example, too much sugar could cause improper freezing by oversaturating the solution, or too much fat (or fat incorporated incorrectly) could cause the mixture to become grainy or separate.
If you are using a recipe that calls for eggs, make sure that you mix them with the listed amount of sugar thoroughly before tempering them with the hot cream/milk solution. Additionally, make sure that you only pour a little bit (quarter - half cup) of the solution into the egg mixture at first, stirring thoroughly, before adding the rest. This assures that the eggs do not curdle when heated, which could cause a grainy texture.
Finally, make sure that you are freezing the mixer bowl overnight, using chilled ingredients, and allowing the machine to run for the full 20-25 minutes. The ice cream should be a bit softer than the consistency of soft-serve when you take it out of the machine - easily scoopable with a spatula. If you like it firmer, an 8 to 48 hour freezer session will greatly improve the texture in my opinion.
Hope this helps!
on Feb 22, 2013