Why Fondue Cheese Separating?

If a fondue is starting to separate then adding cornflour (cornstarch) mixed with a little cold water usually brings it back together again as the cornflour binds moisture to the cheese solids. However if the fondue has turned into a solid lump of cheese then it is most likely that it has been overheated.

How do you keep cheese fondue from separating?

If it gets too thin, decrease the heat and add more cheese. If it begins separating, raise the heat and whisk it back together, or add a little cornstarch (it and flour act as binders, keeping fondue from separating back into liquid and semisolids).

What causes cheese fondue to separate?

Cheese fondue, such as Nigella's Cheese Fondue (from Nigella Express and on the Nigella website), is usually a fairly easy dish to make and if the cheese has separated it is usually because the heat used to melt the cheese was either too high or too low.