Steam distillation separates what can ride vapor from what must stay behind.
Steam distillation passes vapor through aromatic material, carries eligible volatile compounds to a condenser, and collects a distillate that can divide into essential oil and hydrosol. The method depends on volatility, vapor pressure, condensation, and phase behavior.
The failure is asking steam to carry total flavor. Steam can carry volatile aroma. It does not carry sugars, most acids, heavy pigments, tannins, fixed fats, large pungent molecules, or browned matrix structure as the main culinary load in the same way; exact exclusions remain source-dependent.
The constraint is vapor eligibility. If the target compound family cannot vaporize or co-distill under the process conditions, the collected liquid may smell recognizable but taste incomplete.
Use steam distillation when the desired fraction is volatile and heat-tolerant enough for the process. Route color, acid, bitterness, body, pungency, fat, and roast depth to infusion, tincture, fat extraction, emulsion, or another carrier. This is method selection, not a still-building guide.
Validate the method with matching the collected fraction to the culinary job. Citrus peel, some florals, and some herbs can reward steam. Hibiscus color, piperine heat, and Maillard structure expose its limits.
