Pastry and Bakery Products
Senior 1 · Home Science
Pastry and Bakery Products
Lesson 3 of 4
22 min
Let's begin
Swap one ingredient and a recipe changes completely. Use bread flour instead of cake flour and a sponge turns tough. Forget the baking powder and queen cakes come out flat and heavy. Use too much bicarbonate of soda and mandazi taste bitter and soapy. A good baker knows not only what goes into a recipe but why, so that she can choose the right ingredient, spot a fault and make sensible substitutions.
In this lesson you will learn to identify the main pastry and bakery ingredients, what each one does, the four ways mixtures are raised, and how to check that ingredients are fresh.
Wheat flour gives structure. Its proteins form gluten when mixed with water, and its starch sets when heated. Flours are chosen by their protein content:
| Flour | Protein (approx.) | Best for |
|---|---|---|
| Strong (bread) flour | 12 to 14% | Yeast breads, puff pastry, filo: a strong, stretchy gluten |
| Plain (all-purpose) flour | 10 to 12% | Shortcrust pastry, biscuits, mandazi, chapati |
| Pastry and cake (soft) flour | 6 to 9.5% | Tender cakes and delicate pastry |
| Self-raising flour | Plain flour with baking powder already mixed in | Cakes, scones |
| Wholemeal flour | Contains the whole grain, including bran | Adds fibre and flavour; gives a heavier result |
Cassava, maize, sorghum, banana and soya flours contain no gluten, so they cannot make light pastry or bread on their own, but they can replace part of the wheat flour in biscuits, cakes and mandazi.
| Fat | Features |
|---|---|
| Butter | Best flavour and colour; about 80% fat, the rest mostly water; softens quickly in a warm kitchen; expensive |
| Margarine | Cheaper; block margarine is good for pastry, soft margarine for creaming cakes |
| Lard and white vegetable fat (shortening) | Almost 100% fat; no flavour; gives a very short, crumbly pastry |
| Cooking oil | Liquid; used in some doughs and cakes (chapati, mandazi, oil cakes), but cannot make layered pastry |
Functions of fat: makes pastry short or flaky by coating the flour and separating layers; traps air when creamed with sugar; adds flavour and colour; keeps cakes moist and fresh for longer.
Types: granulated (general use), caster (fine crystals, for creaming and sponges), icing sugar (a powder, for icing and dusting), brown sugar (moist, with a caramel flavour) and honey.
Functions: sweetness; tenderness (it softens the gluten); a golden-brown colour (caramelisation); keeps cakes moist; food for yeast; helps trap air when creamed with fat.
| Raising agent | How it is added or made | Examples |
|---|---|---|
| Air | Sifting, rubbing in, creaming, whisking, folding; folding and rolling pastry | Sponges, scones, shortcrust |
| Steam | Water in the mixture turns to steam in a hot oven | Choux, puff and flaky pastry, batters |
| Biological: yeast | Yeast ferments sugar, giving carbon dioxide | Bread, buns, croissants, some mandazi |
| Chemical | Bicarbonate of soda or baking powder gives carbon dioxide when wet and heated | Cakes, scones, many mandazi, soda bread |
Bicarbonate of soda (baking soda, sodium hydrogencarbonate, NaHCO3) is an alkali. It gives off carbon dioxide quickly when it meets an acid, such as sour milk, yoghurt, lemon juice or vinegar. Heated without an acid it still gives some gas, but it also leaves sodium carbonate, which gives a bitter, soapy taste and a yellow colour:
2NaHCO3 → Na2CO3 + H2O + CO2
Baking powder is bicarbonate of soda already mixed with a dry acid and a little starch (which keeps the powder dry). It needs no extra acid. "Double-acting" baking powder gives some gas when mixed and more when heated in the oven.
Task: A recipe for queen cakes needs 500 g of self-raising flour, but the school has only plain flour and baking powder. A common guide is about 1 teaspoon of baking powder for every 125 g of plain flour. How much baking powder should be added?
Solution: Number of 125 g portions = 500 ÷ 125 = 4. Baking powder = 4 × 1 = 4 level teaspoons. Sift the flour and baking powder together twice so the powder is spread evenly; otherwise some cakes rise too much and others not at all.
Tip
Memory hook for raising agents: "A Strong Yeast Chemist": Air, Steam, Yeast (biological), Chemical.
Exam technique: a function question needs the ingredient, the function and the effect on the product, e.g. "egg aerates a sponge: whisking traps air, which expands in the oven and makes the cake light".
Which flour is best for puff pastry and why?
Solution: Strong flour. Its high protein forms strong, stretchy gluten that holds the thin layers during the many rollings and folds.
Give three functions of eggs in baking.
Solution: Any three of: aerating; binding and setting; emulsifying; glazing; adding colour, flavour and nutrients.
Name the four types of raising agent and give one example of a product for each.
Solution: Air (sponge cake); steam (choux pastry); yeast (bread); chemical (queen cakes with baking powder).
A batch of mandazi made with bicarbonate of soda but no sour milk tastes bitter and soapy and looks yellow. Explain why.
Solution: With no acid, the bicarbonate breaks down in the heat into sodium carbonate, water and carbon dioxide. The sodium carbonate is strongly alkaline and gives the bitter, soapy taste and yellow colour. Adding an acid (sour milk, yoghurt, lemon) or using baking powder prevents this.
How much baking powder is needed to turn 750 g of plain flour into self-raising flour, at 1 teaspoon per 125 g?
Solution: 750 ÷ 125 = 6, so 6 level teaspoons.
Summary
Sources and credits
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
