Leavening For Scones

Our answer

Lily's Scones (from HOW TO BE A DOMESTIC GODDESS) have a combination of bicarbonate of soda (baking soda) and cream of tartar as leavening agents. The two come in combination as bicarbonate of soda (baking soda) is an alkaline and needs the addition of an acid, such as cream of tartar, to create the carbon dioxide that causes the scones to rise.

The amount of cream of tartar - 4 1/2 teaspoons - is correct. Baking powder is made from a combination of bicrabonate of soda plus an acid (usually cream of tartar) in a 1:2 ratio, so this amount is close to a baking powder mixture. Also to make the equivalent of self-raising (self-rising) flour, Nigella usually adds 2 teaspoons of baking powder for each 150g plain (all-purpose) flour so for 500g flour you would need 6 1/2 teaspoons of baking powder (equivalent to 2 teaspoons bicarbonate of soda plus 4 1/2 teaspoons cream of tartar). The combination of the two leavening agents is traditional for scones and is useful as they act quickly once mixed together, which helps to make the scones light as the baking time is short. However, cream of tartar can be difficult to find in some places so if it is not available in your area then you could replace the cream of tartar and bicarbonate of soda with 6 1/2 teaspoons of baking powder.