Stocks, Soups, Sauces, and Seasoning
Core concepts
Stocks are the foundation of soups and sauces. Candidates must know the difference between white and brown stocks, the role of bones, mirepoix, aromatics, and the importance of skimming and gentle simmering to keep stock clear. Understand the five mother sauces and their derivatives - béchamel, velouté, espagnole, hollandaise, and tomato - and the thickening agents: roux, slurry, liaison, and reduction. Know the difference between a stock and a broth, and how to cool and store stocks safely. Soups range from clear (consommé, broth-based) to thick (purée, cream, chowder), each with distinct techniques. Seasoning is about balance: salt, acid, fat, sweetness, and umami, and the principle of layering seasoning throughout cooking and finishing to taste.
Traps to watch
Questions often confuse a roux with a slurry, or test which mother sauce a derivative belongs to (e.g., Mornay from béchamel). Watch for scenarios where a stock boils vigorously and becomes cloudy, or where a sauce breaks and the fix requires re-emulsifying. Another trap is over-seasoning early versus adjusting at the end.
Rule of thumb
Simmer stocks gently and skim; never boil hard if clarity matters. For sauces, remember roux thickens by starch gelatinization and needs cooking to remove raw flour taste. Season in layers, taste often, and finish with acid to brighten. Worked example: a broken hollandaise can often be rescued by whisking it slowly into a fresh warm yolk base.