As this is a lemon cheesecake we’re talking about, you’re definitely looking for a certain amount of sour. However, it shouldn’t be too sour. If this is the case, the problem most likely comes from the filling. It contains cream cheese, which has a slight sour taste. If you’ve followed the recipe, this sour taste will have been balanced by the icing sugar.  So, if there is a sour taste, it’s most likely a result of a lack of icing sugar. Don’t forget to always use kitchen scales when weighing out ingredients and always follow the recipe.