Cakes, Sponges and Cookies: Mixing, Formula Balance and Faults
Domain 4 asks you to match a product to its mixing method, check whether a formula is balanced, and diagnose a fault from its symptom. Answers gain marks for naming the cause precisely - “curdled batter from adding egg too quickly”, not “wrong mixing”.
Mixing methods
- Creaming: fat and sugar beaten first, then egg slowly, then dry and liquid alternately - butter cakes, cookies.
- Foaming or whipping: eggs and sugar whipped to a stable foam, fat omitted - sponges, roulade, savarin.
- Blending or all-in: all ingredients together, used with high-ratio emulsified shortening.
- Rubbing-in: cold fat rubbed into flour - shortcrust and rock buns.
Formula balance
In a high-ratio cake, sugar must not exceed flour, and total liquid (eggs plus milk) must at least equal the sugar so it dissolves; the shortening should be emulsified type. Too much sugar gives collapse and a sticky crust; too little liquid gives a dry, crumbly cake and tunnels.
Common faults
- Tunnels: over-mixing after the flour is added, or an oven too hot.
- Sinking centre: under-baking, or excess sugar/liquid.
- Cracked domed top: oven too hot, tin over-filled.
- Cookies spreading too much: warm dough, too much sugar or liquid, low oven.
Worked example
A layer-cake formula: flour 100 %, sugar 95 %, eggs 50 %, milk 40 % (liquid 90 %). Check: sugar 95 ≤ flour 100 - acceptable. Liquid 90 < sugar 95 - the sugar cannot fully dissolve, so the cake will be heavy and may sink. Raise milk to 50 % so liquid = 100 %, or drop sugar to 90 %. Confirm with the batter: it should ribbon, not flood off the beater.
Traps that cost marks
- Adding eggs in one go and curdling the creamed fat.
- Tapping the tin to level batter, which knocks out air; smooth with a palette knife instead.
- Over-folding a sponge and destroying the foam.
- Judging doneness by colour only; test with a skewer or press the centre.