Cakes
What this domain tests
Cakes tests method selection, formula balance, aeration, pan scaling, baking and finishing. Questions often ask why a cake domed, fell, tunnelled or dried out, so link each fault to ingredient balance, mixing or oven conditions.
Core rules
- Methods. Creaming produces butter cakes with a fine, tender crumb. High-ratio cakes use emulsified shortening and a two-stage mix; the formula has sugar at or above flour weight and total liquid, including eggs, at or above sugar weight. Foam cakes such as sponge and angel food depend on whipped eggs or egg whites for structure; chiffon adds oil and chemical leavening to a foam base.
- Ingredient functions. Sugar tenderizes, retains moisture and delays starch set; fat shortens gluten and carries flavour; eggs coagulate and emulsify; liquid hydrates flour and sugar; leavening supplies gas. Rebalancing one ingredient changes texture and volume.
- Scaling and baking. Keep batter depth constant when changing pan size. Prepare pans evenly, bake at roughly 175–190 °C, and test with a skewer or by touch. Cool in the pan briefly, then turn out to prevent sogginess.
Worked example
A 20 cm round pan formula is scaled to a 23 cm round pan of the same depth. Area ratio = (23 ÷ 20)² = 1.3225, so multiply every ingredient by 1.32. If the original formula uses 1,000 g flour, the new formula uses 1,322 g. The reasoning is that batter depth, not diameter, determines baking time; matching area ratio keeps depth and therefore time roughly constant.
Traps that cost marks
Overmixing high-ratio batter after adding flour; underbaking dense batters; opening the oven door early; using the wrong pan size without recalculating; assuming a fallen cake is always underbaked when it may be overbeaten or over-leavened; and cooling foam cakes in the pan, which causes collapse.
Key points
- High-ratio cakes need sugar at or above flour and liquid at or above sugar.
- Foam cakes rely on egg-protein foam; chiffon adds oil and leavening.
- Sugar tenderizes and retains moisture; fat shortens gluten.
- Scale pan sizes by area ratio to keep batter depth constant.
- Overmixing after flour addition causes toughness and tunnels.
- Cool foam cakes upside down or as specified to prevent collapse.
Chocolates, Confections and Frozen Desserts
What this domain tests
This domain covers chocolate tempering and crystallization, sugar confections, ganache and frozen desserts. The exam tests temperature ranges, crystal types, sugar stages, emulsion stability, overrun and freezing-point control.
Core rules
- Tempering. Dark chocolate: melt to 45–50 °C, cool to about 27 °C, reheat to 31–32 °C. Milk and white chocolate temper at 29–30 °C. Tempering produces stable Form V (beta) cocoa-butter crystals, which give snap and gloss. Fat bloom is grey streaking from unstable crystals or heat; sugar bloom is a rough white film from moisture.
- Confections. Sugar stages run from thread (110–112 °C) through soft ball (113–116 °C), firm ball (118–120 °C), hard ball (121–130 °C), soft crack (132–143 °C) and hard crack (146–154 °C) to caramel (about 160–170 °C). Crystalline confections such as fondant and fudge need seeding and interference to keep crystals small; noncrystalline candies such as hard candy and toffee need interfering agents to prevent crystallization.
- Frozen desserts. A typical ice cream base balances fat, milk solids, sugar and stabilizers. Overrun is the percentage of air by volume. Freezing-point depression from sugars and alcohol controls scoopability; aging hydrates stabilizers and improves texture.
Worked example
Ten litres of ice cream mix churns to 15 litres of finished ice cream. Overrun = (15 − 10) ÷ 10 × 100 = 50%. If the target is 35%, the finished volume should be 10 × 1.35 = 13.5 L. The reasoning is that overrun is based on mix volume, not finished volume, so dividing by the finished volume understates air incorporation.
Traps that cost marks
Overheating chocolate during melting; letting water contact melted chocolate, which causes seizing; skipping seeding during tempering; stirring sugar syrups after boiling, which starts crystallization; and adding too much sugar or alcohol to a frozen base, which lowers the freezing point and makes the product soft or unset.
Key points
- Dark chocolate tempers at 31–32 °C; milk and white at 29–30 °C.
- Form V cocoa-butter crystals give gloss and snap.
- Sugar stages: soft ball 113–116 °C, hard crack 146–154 °C, caramel about 160–170 °C.
- Crystalline confections require seeding and interference; noncrystalline candies require interference only.
- Overrun = (finished volume − mix volume) ÷ mix volume × 100.
- Excess sugar or alcohol lowers the freezing point of frozen desserts.