Home Ec notes

1. Equipment & Hygiene

  • Mise en place: Prepping, measuring, and chopping all ingredients before turning on any heat source.

  • Measuring: Scales = mass (dry goods); Jugs = liquid volume (at eye level); Spoons = tiny accurate amounts (Tbsp, tsp, \(\frac{1}{2}\) tsp, \(\frac{1}{4}\) tsp).

  • Saucepan Lids: Traps steam to cook food faster and conserve thermal energy.

  • Colour-Coded Boards: Prevents cross-contamination (bacterial transfer):

    • đź”´ Red: Raw red meat

    • 🟡 Yellow: Cooked meat/deli

    • 🔵 Blue: Raw fish/seafood

    • 🟢 Green: Salads, fruits, and raw vegetables

    • ⚪ White: Dairy and bakery items

    • 🟤 Brown: Earthy/root vegetables (soil-covered)

2. Principles of Cooking

  • Core Goals: Destroys pathogenic microbes (safety: Salmonella, E. coli); softens cellulose/plant fibers and animal connective tissue (easier to digest); improves taste, aroma, and look.

  • Changes: Causes moisture loss (weight drops), protein coagulation (firms up), and browning reactions (Caramelisation / Maillard reaction).

3. Heat Transfer Methods

  • Conduction: Heat moves via direct physical contact particle-to-particle (e.g., hot hob element → base of metal pan → food).

  • Convection: Heat moves via circulating currents in a moving liquid or gas. Hot molecules expand, lighten, and rise; cooler, denser molecules sink (e.g., boiling water, baking in a fan oven).

  • Radiation: Heat moves via infrared electromagnetic waves in straight lines. Requires no contact or fluid medium; hits food surface directly (e.g., overhead radiant grill element, toaster).

4. Cooking Methods

  • Boiling: Fully submerged in liquid rapidly bubbling at 100°C. Disadvantage: Destructive to shapes; leaches nutrients.

  • Simmering/Stewing: Gentle cooking just below boiling point (85°C–90°C). Slow heat dissolves tough meat tissue (collagen) into soft gelatin.

  • Steaming: Cooked strictly in rising water vapor above liquid. Healthiest moist method: prevents water-soluble vitamins (B and C) from leaching out into water.

  • Frying: Shallow (minimal oil) vs. Deep-fat (completely submerged) vs. Stir-frying (rapidly tossing uniform pieces in a wok).

5. Sauce Science (Gelatinisation)

  • Definition: Chemical thickening of a liquid using a starch (flour).

  • Temperature Timeline:

    1. Heated starch granules absorb liquid and swell.

    2. At 60°C, granules lose structural integrity and burst open.

    3. Burst granules release amylose starch chains, trapping liquid molecules.

    4. At 100°C (Boiling), the network sets fully into a thick, smooth, viscous gel.

  • Roux Method: Melt equal parts fat (butter) and flour together to make a paste (roux); cook out raw taste, then gradually whisk in cold milk before boiling.

  • All-in-One Method: Cold milk, flour, and butter are placed in a pan simultaneously from the start and whisked non-stop with a balloon whisk over heat until boiling.

6. Presentation & Accents

  • Meal Accompaniments: Edible side dishes or sauces served with a main to balance nutrition/texture (e.g., rice with curry, garlic bread with lasagna).

  • Garnishes: Small, edible decorations added strictly to savory dishes for visual color contrast (e.g., parsley sprig on soup, lemon twist on fish).

  • Golden Rule: Combine contrasting textures and vibrant colors. Always wipe the plate rim completely clean of smudges, fingerprints, or splashes before serving ("we eat with our eyes first").