At what point is a stock considered done" and fully extracted

Question

and what are signs that continuing to cook is no longer beneficial (or could even harm the flavor)?"

Answer 1

A stock is considered 'done' when it has reached its maximum flavor extraction, typically after several hours of simmering, and the solids have given up most of their flavor. Signs of over-extraction include a bitter, muddy, or overly gelatinous taste, and the stock may become cloudy.

Detailed Explanation:

Determining when a stock is 'done' is a balance between extracting maximum flavor and avoiding over-extraction. The process involves simmering bones, vegetables, and aromatics in water for an extended period. Here's a breakdown:

1. Initial Extraction: During the first few hours, the stock releases collagen from the bones, which converts to gelatin, giving the stock body and richness. Flavors from the vegetables and aromatics also infuse into the liquid.
2. Peak Flavor: This is the sweet spot. The stock has a deep, savory flavor, a good amount of gelatin, and a clear appearance. The bones should be somewhat brittle and easily crushed. The vegetables will be soft and have lost most of their color.
3. Over-Extraction: Continuing to cook beyond the peak can lead to problems. The bones can start to release undesirable flavors, such as bitterness from the marrow. Vegetables, especially those from the brassica family (cabbage, broccoli, etc.), can become overly strong and muddy the flavor. The stock may also become excessively gelatinous, which can be unpleasant. Cloudiness can also indicate over-extraction, as proteins break down further.
4. Timing Guidelines:
   • Chicken Stock: Typically 3-4 hours is sufficient.
   • Beef or Veal Stock: 6-8 hours is usually ideal.
   • Vegetable Stock: 1-2 hours is often enough, as vegetables release their flavors more quickly.
5. Tasting is Key: The best way to determine doneness is to taste the stock periodically. Start tasting after the minimum recommended time and continue until you are satisfied with the flavor. If it starts to taste bitter or muddy, it's time to stop.

Pro Tip:

To prevent over-extraction, remove the vegetables from the stock after they have contributed their flavor (usually after about 1-2 hours for vegetable stock, or halfway through the cooking time for meat stocks). This prevents them from breaking down further and releasing bitter compounds.