Emulsion: Mayonnaise & Aioli
The most commonly made sauce in every professional kitchen, and also the one most often thrown away. In my first year in the kitchen I wasted at least five liters of mayo, always for the same reason: pouring the oil too fast. You know this. You were taught this. And yet you still rush it when service is about to start. This is the technique as it appears in the textbooks, plus the honest story of when it goes wrong.
In brief
Mayonnaise is a stable oil-in-water emulsion of egg yolk, vegetable oil, acid, and mustard. Lecithin in the egg yolk, roughly 10% of the yolk's weight, acts as the emulsifier: its hydrophobic tails are attracted to the oil, while its hydrophilic heads face the water. This creates a stable network of micro oil droplets suspended in a water phase. Mustard reinforces this network through mucilage in the mustard seed.
- Emulsion type: oil-in-water (O/W). Oil is the dispersed phase, water is the continuous phase. This is why mayonnaise appears white: light reflects off the tiny oil droplets. (McGee, On Food and Cooking, Scribner 2004, p.625)
- Lecithin content of egg yolk: approximately 10% of its weight, sufficient to emulsify 70-80% oil by volume. Exceed that ratio and the lecithin becomes depleted: the emulsion breaks. (McGee 2004, p.626)
- Mustard as co-emulsifier: mucilage in mustard seed reinforces the lecithin layer surrounding each oil droplet, making the emulsion more stable during temperature fluctuations. (CIA Professional Chef, 9th ed., Wiley 2011, Ch.25)
- Role of pH: vinegar or lemon juice lowers it to pH 3.6-4.0. This stabilizes the emulsion AND inhibits Salmonella growth, but does not eliminate the bacterium. (FDA Food Code 2017, §3-501.16)
- Aioli origin: Provencal, from "ail" (garlic) and "oli" (oil) in Occitan. Traditionally made without egg: the emulsion relies on garlic starch and proteins. Modern restaurant versions add egg yolk for stability. (Larousse Gastronomique, Editions Larousse 2009, p.20)
Six classic variants
Classic Mayonnaise
Neutral base of sunflower oil, egg yolk, Dijon mustard, white wine vinegar, and salt. The standard for salads, garnishes, and as a base for all derivatives. Ratio: 1 egg yolk to 200ml oil (Escoffier 1903, #141).
Examples: Salade Olivier, garnish, sauce base
Aioli
Olive oil with garlic puree. Traditionally made without egg: the garlic proteins and starch form the emulsion. Modern versions add egg yolk for stability. Intense in flavor, less heat-stable than mayonnaise due to the polyphenols in olive oil. (Larousse Gastronomique 2009, p.20)
Examples: Bouillabaisse, grilled fish, roasted vegetables
Rouille
Aioli with saffron, paprika, and cayenne pepper. The classic accompaniment to Marseilles bouillabaisse. Color: orange-red from the saffron. Same HACCP rules as aioli: raw egg, max 7°C/45°F, maximum 3 days.
Examples: Bouillabaisse, fish soups, croutons
Remoulade
Mayonnaise with finely chopped capers, cornichons, tarragon, parsley, and anchovy. Classic with cold meats, celeriac salad, and fried fish. Escoffier describes remoulade in recipe #153 as a "mayonnaise relevee": an elevated mayo.
Examples: Vitello tonnato, cold cut platter, coleslaw
Tartare Sauce
A remoulade variant with extra cornichon, chives, and sometimes hard-boiled egg folded into the sauce itself. Fresher and lighter than remoulade. A classic accompaniment to fried fish in European hospitality. (CIA Professional Chef 2011, Ch.25)
Examples: Fish & chips, shrimp croquettes, fish burger
Caesar Dressing
Mayo base with anchovy, Worcestershire, lemon juice, garlic, Parmesan, and Dijon. Invented by Caesar Cardini in Tijuana, Mexico, 1924. Note: also contains raw egg. Same HACCP rules as mayonnaise.
Examples: Caesar salad, wraps, grilled chicken
Sources: Escoffier, Le Guide Culinaire (1903), recipes #141 and #153; CIA Professional Chef, 9th edition (2011), Chapter 25; Larousse Gastronomique (2009), p.20
Rescuing broken mayonnaise: three methods that work
Method 1: Fresh egg yolk
Start with a fresh egg yolk in a clean bowl. Add the broken mayo drop by drop as if it were oil. Works every time, even with a completely separated emulsion. It does cost you an extra yolk.
Works for: completely separated mayo
Method 2: Ice-cold water
For a slightly broken emulsion: add 1 tablespoon of ice-cold water and whisk vigorously. The cold water temporarily stabilizes the lecithin layer. Does not work for fully separated mayo, but effective at the early signs of separation.
Works for: early signs of separation
Method 3: Immersion blender rescue
Pour the broken sauce into a tall narrow cup. Add 1 fresh egg yolk at the bottom. Place the immersion blender at the bottom, start on low. Pull up slowly. In 90% of cases you will restore the emulsion within 30 seconds.
Works for: most cases
Step by step: mayonnaise done right
-
1
Mise en place: everything at room temperature
Take eggs and oil out of refrigeration at least 30 minutes before preparation. At 4°C/39°F, lecithin is too viscous to properly coat oil droplets: the emulsion is unstable from the very first drop. This is the number one cause of broken mayo in busy kitchens. You know this, but you still take them out too late when you are in a rush.
Forgot to temper the eggs? Five minutes in lukewarm water at 30°C/86°F. Not warmer, or you will begin to cook the egg. -
2
Create the water phase: yolk, mustard, salt, and vinegar
Whisk 1 egg yolk (20-25g) with 1 teaspoon Dijon mustard, a pinch of salt, and 1 tablespoon white wine vinegar until homogeneous. This is the water phase of your emulsion. The mustard is not just there for flavor: the mucilage in mustard seed reinforces the lecithin layer around each oil droplet, making the final sauce measurably more stable. (CIA Professional Chef 2011, Ch.25)
Use a tall, narrow measuring cup with an immersion blender. A wide bowl provides too little friction in the initial phase. -
3
The critical phase: first 50ml of oil, drop by drop
Add the first 50ml of oil in an extremely thin stream or drop by drop, while whisking continuously or running the immersion blender on low. You are now building the core emulsion: each oil droplet is being surrounded by lecithin. Go too fast and you overwhelm the available lecithin, causing the emulsion to break immediately.
Working in a bowl? Place it on a damp cloth so it does not slide. A spinning bowl while you are adding oil is the second most common cause of broken mayo. -
4
Add oil in a thin stream
Once you have a thick, pale emulsion from the first 50ml, add the rest in a thin but continuous stream. Total: 200-240ml oil per egg yolk. This is the Escoffier standard from 1903, recipe #141, and still the most widely used ratio in professional kitchens. More than 240ml per yolk: you risk separation at the end.
A mayo that is nearly done but still breaks: almost always too much oil. Stop in time. A slightly too-thin mayo is better than a broken one. -
5
Season to taste and adjust consistency
Season with salt, additional vinegar or lemon juice, and optionally white pepper. The correct consistency: the mayo falls from a spoon but leaves a visible trail behind, the so-called nappe consistency for cold sauces. Too thick: add a teaspoon of lukewarm water while whisking slowly.
Always taste with a clean spoon. Cross-contamination from a used spoon can halve the shelf life. -
6
Chill, label, and store per HACCP
Transfer immediately to a properly sealed container and refrigerate below 7°C/45°F. Labeling is mandatory: contents, preparation date, name of responsible person, use-by date (3 days including the day of preparation). This is not optional in professional kitchens: it is a HACCP documentation requirement.
Maximum 3 days at max 7°C/45°F. For vulnerable guests (pregnant women, elderly 65+, immunocompromised individuals), use only pasteurized egg yolk. (NVWA Hygiene Code for Hospitality 2023, section Raw Egg Yolk Products; FDA Food Code 2017, §3-801.11)
HACCP: Raw Egg Yolk, Salmonella Protocol
Mayonnaise, aioli, and caesar dressing contain raw egg yolk. Salmonella Enteritidis survives in raw eggs and is not eliminated by lowering the pH with vinegar or lemon juice. The NVWA Hygiene Code for Hospitality (2023) and the FDA Food Code (2017, §3-501.16) prescribe specific protocols.
Salmonella Enteritidis in raw egg yolk
Salmonella Enteritidis can be present in apparently intact eggs, even with an undamaged shell. The contamination is endogenous, inside the yolk itself, not only on the exterior. The pH reduction through vinegar or lemon juice (pH 3.6-4.0) slows bacterial growth but does not eliminate the bacterium at room-temperature preparations.
NVWA/FDA protocol: prepare raw egg yolk preparations at a maximum kitchen temperature of 20°C/68°F, chill immediately to below 7°C/45°F, and store for a maximum of 3 days including the day of preparation.
Source: NVWA Hygiene Code for Hospitality (2023), section Raw Egg Yolk Products; EU Regulation (EC) 853/2004 Annex III, Section X (Eggs and Egg Products); FDA Food Code 2017, §3-501.16
Vulnerable groups: use pasteurized egg yolk
Pregnant women, elderly (65+), immunocompromised individuals, and young children (under 5) face an elevated risk of serious complications from a Salmonella infection. For healthcare catering, childcare, and elderly care, the NVWA Hygiene Code mandates the use of pasteurized liquid egg yolk for preparations that are not further heated. The FDA Food Code (2017, §3-801.11) similarly restricts raw or undercooked eggs for highly susceptible populations.
Pasteurized egg yolk: unopened shelf life of 5-6 weeks at 2-4°C/36-39°F; after opening, maximum 3 days.
Source: NVWA Hygiene Code for Hospitality (2023), section Risk Groups; FDA Food Code 2017, §3-801.11; Codex Alimentarius CAC/RCP 1-1969 (revised 2020)
HACCP reference table: mayonnaise & cold emulsion sauces
| Product | Risk | Storage temp | Max shelf life | Source |
|---|---|---|---|---|
| Homemade with raw egg | Salmonella Enteritidis | < 7 °C | 3 days | NVWA 2023 |
| Aioli with raw egg | Salmonella Enteritidis | < 7 °C | 3 days | NVWA 2023 |
| Caesar dressing with raw egg | Salmonella + Listeria | < 7 °C | 3 days | FDA Food Code 2017 |
| Commercial pasteurized | Low (pH < 4.1) | < 7 °C after opening | 14-30 days after opening | FDA Food Code 2017 |
| Pasteurized liquid yolk | Minimal | 2-4 °C | 3 days after opening | EU 853/2004 |
Mayonnaise vs Aioli: five key differences
| Aspect | Mayonnaise | Aioli |
|---|---|---|
| Base oil | Sunflower or grapeseed oil | Extra virgin olive oil |
| Emulsifier | Lecithin (egg yolk) + mustard | Garlic proteins + starch (+ optional egg) |
| Flavor | Neutral, mildly acidic | Intense, garlic-dominant, fruity |
| Heat stability | Relatively stable up to 45°C/113°F | More fragile due to EVOO polyphenols |
| Classic use | Salads, sauce base, garnish | Mediterranean, fish, roasted vegetables |
Mayonnaise is the one sauce every cook knows and yet half of them get wrong. Oil too cold, added too fast, no mustard. Three mistakes, each with the same result: five minutes of wasted time and a broken emulsion you have to rescue before service.
Jeffrey Smit, former kitchen manager
Food cost: making your own vs buying commercial
- Material cost homemade (1 liter): 4 egg yolks (~60g, ~$0.70) + 800ml sunflower oil (~$0.90) + vinegar, mustard, salt (~$0.15) = approximately $1.75 per liter. Commercial (Hellmann's, Calve foodservice pack): $4.00-5.00 per liter. Material advantage: 60-65%.
- But factor in labor costs. Preparation takes 15-20 minutes per liter including mise en place, emulsification, and cleanup. At $17/hour kitchen staff: $4.25-5.65 extra per liter. At that point commercial is cheaper, unless you produce 5+ liters per day.
- When making your own truly pays off: (1) when freshness is a selling point on the menu, (2) at production volumes of 5+ liters per day where labor cost per liter drops, (3) for aioli and rouille: quality far exceeds commercial products, and premium versions are not available off the shelf.
- Shelf life is the hidden cost driver: homemade lasts max 3 days. Commercial lasts 14-30 days after opening. At low turnover, waste can wipe out the entire material savings. Calculate your daily usage before you decide.
Frequently asked questions: mayonnaise and aioli
Why does my mayonnaise separate?
Almost always one of three causes: (1) cold ingredients: make sure eggs and oil are at room temperature before you start, (2) oil added too quickly in the initial phase: the first 50ml must truly be drop by drop, (3) too much oil overall: above 80% oil by volume, the lecithin is depleted and the sauce separates.
Rescuing broken mayo: start with a fresh egg yolk in a clean bowl and add the broken sauce drop by drop as if it were oil. This works every time. (CIA Professional Chef 2011, Ch.25)
Is homemade mayonnaise dangerous for guests?
The risk is real but manageable. Raw egg yolk can contain Salmonella Enteritidis. The NVWA prescribes: maximum 3 days at max 7°C/45°F, immediate refrigeration after preparation, and for vulnerable guests (pregnant, elderly 65+, immunocompromised) the exclusive use of pasteurized egg yolk. The FDA Food Code (2017, §3-801.11) has equivalent restrictions for highly susceptible populations.
For the average guest who does not belong to a risk group: the risk is comparable to other raw egg preparations. Strict compliance with the storage protocol is the only thing that counts. (NVWA Hygiene Code for Hospitality 2023)
What is the real difference between aioli and mayonnaise?
Traditional aioli from Provence contains no egg. It is olive oil emulsified with garlic puree using the starch and protein structure of the garlic itself. Modern restaurant usage adds an egg yolk for stability, but technically speaking that is garlic-flavored mayonnaise.
In terms of flavor: mayonnaise is neutral and versatile, aioli is intense and specific. Use aioli only where the olive oil flavor and garlic are integral to the culinary concept. (Larousse Gastronomique 2009, p.20)
Which oil should I use for the best neutral mayonnaise?
Sunflower oil or grapeseed oil. Olive oil in larger quantities produces a bitter, sometimes soapy result: the intense polyphenols in extra virgin olive oil react during vigorous mixing with the emulsifier in a way that amplifies bitterness.
Exception: for aioli, olive oil is not only acceptable but essential. Use a fruity, mild extra virgin. A sharp, peppery olive oil will produce an unpleasant sauce.
How long does homemade mayonnaise last?
Maximum 3 days at max 7°C/45°F, including the day of preparation itself. This is the standard from the NVWA Hygiene Code for Hospitality (2023) for raw egg yolk products. Always label with: contents, preparation date, name of responsible chef, and use-by date.
Commercial mayo with pasteurized egg and pH below 4.1: 14-30 days after opening at max 7°C/45°F. The low pH strongly inhibits bacterial growth but is not sterilization. Always check the specific use-by date on the packaging.
Can I freeze mayonnaise for longer shelf life?
No. Freezing irreversibly destroys the emulsion. Ice crystals break the lecithin layer around the oil droplets. After thawing you are left with a separated mixture of greasy liquid and watery pools: no longer mayo.
If you regularly have surplus: calculate your daily usage and halve your batch size. Three days of shelf life leaves little margin when service falls short. Smaller batches are the smarter choice in this case.
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Food safety & HACCP
The HACCP guidelines, temperatures and storage advice on this page are based on Codex Alimentarius (WHO/FAO) as the global baseline standard and EU Regulation 852/2004. Local laws and regulations may differ. Always consult your national food safety authority for the applicable standards in your region:
- Netherlands: NVWA (nvwa.nl)
- Belgium: FAVV (favv-afsca.be)
- Germany: BfR (bfr.bund.de)
- United Kingdom: FSA (food.gov.uk)
- United States: FDA (fda.gov) — FDA Food Code
- EU general: EU Regulation (EC) 852/2004 on food hygiene
- International: Codex Alimentarius CAC/RCP 1-1969 (revised 2020)
Allergens & dietary information
Allergen information is indicative. When in doubt about allergens in preparations, always contact the supplier or a certified allergological adviser. KitchenNmbrs accepts no liability for allergic reactions or diet-related harm.
Copyright & sources
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- Escoffier, Auguste. Le Guide Culinaire. Flammarion, Paris, 1903. Recipes #141 (Sauce Mayonnaise) and #153 (Remoulade). Primary historical source for classic ratios.
- McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. Scribner, New York, 2004. pp.625-628 (emulsions, lecithin, mayonnaise). Scientific reference for emulsion chemistry.
- The Culinary Institute of America (CIA). The Professional Chef, 9th edition. Wiley, Hoboken, 2011. Chapter 25: Cold Sauces and Salad Dressings. Professional kitchen standard.
- NVWA. Hygiene Code for Hospitality, 2023 edition. nvwa.nl. Section: Raw Egg Yolk Products, storage temperatures, risk groups. Dutch regulatory framework.
- Larousse Gastronomique. Editions Larousse, Paris, 2009. p.20 (Aioli) and p.746 (Mayonnaise). Culinary encyclopedia and historical definition source.
- FDA Food Code 2017. U.S. Food and Drug Administration, Washington DC. §3-501.16 (Temperature and Time Control), §3-301.11, §3-801.11. International food safety reference framework.
- EU Regulation (EC) No. 853/2004 of the European Parliament and of the Council of 29 April 2004. Annex III, Section X: Eggs and Egg Products. European legal framework for egg products in the hospitality industry.
HACCP guidelines are based on NVWA Hygiene Code for Hospitality (2023), EU Regulation 852/2004, EU Regulation 853/2004, and FDA Food Code 2017. Local regulations may vary. Consult your regional NVWA office, local health department, or a certified food safety advisor for your specific situation.
