Aromatic bases & spice pastes
white mirepoix
mirepoix blanche · A classical French aromatic base of onion, carrot, and celery sweated gently in butter or other fat until soft and translucent but not colored, used to flavor stocks, sauces, soups, and braises. The sweating process releases cellular moisture and water-soluble aromatic compounds without triggering Maillard browning reactions, yielding a clean, bright flavor foundation.
The formula
2 parts onion : 1 part carrot : 1 part celery (by weight)
In classical French kitchens this is further scaled against the finished product: 50–100 g raw mirepoix per liter of stock or sauce. The carrot is optional in some preparations where its sweetness is undesirable; in strict classical tradition carrot is always included.
Identity
- Three-vegetable aromatic foundation (onion-dominant)
- Sweated gently in fat — never browned
- Prepared raw and sweated in butter or neutral fat
- Weight-ratio precision (2:1:1) — not volumetric approximation
- Used as a flavoring, not a serving component — discarded after infusion
Ingredients
| Aromatics | yellow onion | White or yellow varieties only; shallots acceptable in refined applications. Red onion unacceptable — too much pigment, harsh raw flavor that does not mellow when sweated. |
| Aromatics | carrot | Peeled, trimmed. Provides subtle sweetness and body to the aromatic foundation. Occasionally omitted when a purely savory-onion character is desired, as in some fish stocks. The classical tradition always includes it. |
| Aromatics | celery | Stalk celery, including leafy tops for 2–3 cm of the heart. Provides the characteristic savory-pungent backbone. Celeriac is not a substitute here — it belongs to darker mirepoix variants. |
| Fat | unsalted butter | Clarified butter or neutral vegetable oil preferred for higher-heat applications where browning must be strictly avoided. Whole butter is the classical choice for flavor but carries higher browning potential due to milk solids. Use fat equal to approximately 5–10% of the total vegetable weight. |
| Seasoning | fine sea salt | A pinch added during sweating draws out moisture via osmosis, accelerating the release of aromatic compounds and preventing sticking. Add after initial melt, not before. |
Method
- 1Peel and dice all vegetables to a brunoise (3–4 mm cubes) or small dice of uniform size.Uniformity ensures vegetables cook at the same rate. Brunoise is the classical precision cut for mirepoix, providing maximum surface area for compound release while maintaining structure during cooking.
- 2Heat butter (or fat) in a heavy-bottomed sauté pan or saucepan over medium-low heat until foaming subsides.The foaming indicates water evaporation from the fat. Beginning sweating only after foaming subsides prevents steaming rather than sweating, which would cause uneven softening and texture breakdown.
- 3Add all vegetables to the pan, stir to coat in fat, add a small pinch of salt, and place over medium-low heat. Cook uncovered, stirring occasionally, for 8–12 minutes until completely translucent and soft but with no color.Gentle heat extracts water-soluble aromatic compounds — sulfur compounds from onion, polyacetylenes from carrot, phthalides from celery — without reaching the 140–165 °C threshold where Maillard reactions and caramelization begin. Color is the enemy of white mirepoix.
- 4If a small amount of fond has developed on the pan, deglaze with a tablespoon of cold water or stock, swirl, and add back to the mirepoix.The fond contains concentrated aromatic compounds from the vegetables. Incorporating it back ensures no flavor is lost. Cold liquid added to a hot pan creates thermal shock that lifts fond efficiently.
Techniques that matter
Brunoise cut
The 3–4 mm dice maximizes cell-wall rupture and compound extraction while maintaining structural integrity through the sweating process. Too coarse and the vegetables steam; too fine and they collapse into a mush.
Low-temperature sweating
Keeping the pan below 90 °C preserves the pale color and prevents caramelization. This is a solvent-extraction process: the fat acts as a hydrophobic solvent, extracting aromatic lipophilic compounds while water within the vegetables dissolves hydrophilic ones.
Mise en place scaling
Mirepoix is always scaled proportionally to the final volume of liquid being seasoned. Classical French tradition: 50–100 g raw mirepoix per liter of liquid. This ratio is not arbitrary — it reflects the threshold above which aromatics contribute detectable flavor and below which the base reads as flat.
Variations & derivatives
Hay mirepoix (mirepoix paille)France
Vegetables cut into fine julienne (matchstick) rather than diced. Used in refined consommés and white sauces where texture matters. Equal weight ratio still applies but preparation method changes to maximize surface area.
Mirepoix for poisson (fish stock base)France
Carrot sometimes omitted; onion still dominant. Shallots substituted for a portion of onion for a more delicate, marine-compatible aromatic profile. Still sweated, never browned.
SoffrittoItaly
Italian equivalent but with olive oil and typically including garlic; often cooked longer to partial color development. Different philosophy — Italian cooking embraces caramelization in soffritto.
Holy trinity (Cajun/Creole)Louisiana, USA
Onion, celery, and bell pepper — carrot replaced with bell pepper. Cooked in lard or bacon fat, often to some color. A derivative concept rather than a direct variation.
SuprêmesFrance
For classical white sauces and haute cuisine: onion diced very finely, carrot and celery cut to brunoise, then the onion part is sweated separately and combined — prevents overcooking the more delicate onion before carrot and celery soften.
Used in these dishes
Substitutions
- yellow onion → shallots or white onion — Shallots offer a sweeter, more delicate allium note; appropriate for refined fish and poultry applications. White onion is a direct substitute with slightly sharper character.
- celery → celeriac — Celeriac provides a similar savory-woody aromatic profile but a different texture — denser, starchier. Not interchangeable for white mirepoix in stocks; belongs to darker preparations.changes result
- carrot → none (omit) — Acceptable in fish stocks or when a purely savory-onion character is desired. Not advisable in classical brown stocks or consommés where carrot's sweetness provides balance.changes result
Troubleshooting
Vegetables brown during sweating
Heat too high — pan temperature exceeded 140 °C, triggering Maillard reactions and caramelization. Butter will visibly brown and smell nutty rather than gently aromatic. → Remove from heat immediately. If mild, continue at lower temperature with a splash of cold water to arrest browning. If deeply browned, the mirepoix is ruined for white applications — it has become a mirepoix brun and will add amber color and caramelized flavor.
Mirepoix is mushy and waterlogged
Too much water was released too quickly — either from sweating too fast over high heat, or from salting too aggressively before vegetables had a chance to sweat out their moisture. Also occurs if vegetables are cut too finely or are too old and dry. → Drain immediately, spread on a sheet pan, and blot dry. Return to pan over low heat briefly to re-evaporate surface moisture. Use immediately — texture will not improve with standing.
Raw, sharp allium flavor persists after sweating
Insufficient cooking time or temperature — the sulfur compounds in onion have not been adequately broken down through gentle heat application. Also occurs if vegetables were not fully coated in fat. → Continue sweating over medium-low heat, ensuring fat coats all pieces. Add a small splash of water, cover briefly to trap steam and accelerate softening, then uncover to evaporate. The sharp flavor indicates the reaction is incomplete.
Mirepoix burns on the bottom despite low heat
Insufficient fat — not enough butter to coat the vegetables and conduct heat away from the pan surface. Also caused by using an uneven heat source or a pan with hot spots. → Add more butter (or clarified butter for higher smoke point), redistribute vegetables to areas with better heat distribution, and lower the heat source. If fond has formed, deglaze immediately with cold liquid and incorporate back.