I always made wonderful baked cheesecakes that were smooth and silky every time using the Domestic Goddess recipes and baking in a water bath. When I moved to my new house with new oven I seem to have lost the knack. They end up grainy and wet. Do I need to concentrate on the wrapping part or the heat part? I don't want to give up but it's an expensive and disappointing experience!
Many of Nigella's cheesecakes, such as the London Cheesecake, Chocolate Cheesecake and the Pumpkin Cheesecake are baked in a water bath. To prevent water seeping into the cheesecake as it bakes the springform tin is wrapped tightly on the outside with clingfilm (plastic wrap) and foil to form a barrier. It may take several layers of clingfilm and a double layer of foil to make sure that there are no cracks or crevices that the water could creep into.
However from the description of the grainy cheesecake we suspect that the cheesecake is being overcooked. As a cheesecake is set using eggs, it needs a gentle heat and a water bath can help to provide this. If the eggs overcook they turn grainy, hence the texture, and also the proteins contract and force out moisture, which is why the cheesecake may have some liquid seeping out. Often also the surface will crack. If you have changed ovens then the new one can take a while to get used to, particularly if you have gone from a conventional oven to a fan one. Fan ovens can be quite strong and cook much more quickly then conventional ones and usually need to have the temperature reduced. The handbook should indicate the correct adjustment for your oven (usually it is a reduction of around 20C/50F). However as cheesecakes need a very gentle heat it may be wise to turn the oven down an extra 10C/25F on top of this, to make sure that the heat is gentle. The cheesecake may take a little longer to cook in a very low oven but this is probably preferable to it overcooking. The cheesecake should be set around the edges but still have a slight wobble in the centre. Also try to wrap the tin with clingfilm and foil almost all the way up to the rim and cook the cheesecake in a water bath with the water coming at least halfway up the tin, to protect the cheesecake filling from the direct heat of the oven.