Can I use cake flour instead of plain flour for the Chocolate Guinness Cake? Thank you!
Nigella's Chocolate Guinness Cake (from Feast and on the Nigella website) is made with plain (all-purpose) flour that has bicarbonate of soda added to it to help the cake to rise. Plain flour is the flour that is usually available in the UK, and is not sold with any leavening in it. It has a medium level of gluten. This can be checked by loooking at the nutritional information on the packaging; the protein content should be about 11%. This flour is useful as it can be used for pastry and cakes.
Cake flour is made from "soft wheat", which has a lower gluten content. The flour has a protein content of between 7% and 9%. It is good for cakes., particularly ones with lots of added liquid, as less gluten gives a more tender crumb. In the US most cake flour does not contain any added leavening so can be used in the Guinness Cake. However in the UK the cake flour that we have seen so far in stores is sold in "self-raising" form, meaning that it has baking powder added. Unfortunately this means that it is not suitable for the Guinness Cake as adding the bicarbonate of soda as well would mean that the cake would bubble up over the top of the pan while cooking.