I bought these Maris Piper potatoes. In the instructions for deep fry to make chips, it says put in a bowl of water for 30 minutes to remove starch, dry, then fry for 6-9 minutes.  I did so however when eating the potatoes they tasted a bit sweet on the inside. I'm not sure but does this mean the inside wasn't cooked properly?   Usually I believe you need to boil potatoes before frying. Since it didn't say to do this I didn't, would that have caused the result?  The outside layer was quite brown and I think I left it in too long(9 minutes). I also only left it in the bowl for 15 minutes to remove starch.  Does anyone know if I did anything wrong besides maybe leaving it too long which made the outer layer brown?  Does the sweet tasting inside mean anything?  To be honest, the end result tasted like the sweetest chips. I never really experienced it like that before so I'm guessing I did something wrong? 
The sweetness is due to the choice of potato, not your method. Maris pipers have a slightly sweet flavor, if you bake one and taste it you'll get the same result. If you don't like the taste then try other varieties. No need to boil potatoes before frying, a soak and a dry is the way to go.  