Mayonnaise and Emulsions
Cooking Skills: Eggs 2
Chapter 7 · Mayonnaise and Emulsions
Skill goal
Turn oil and yolk into a smooth, stable sauce, and know how to rescue it when it splits.
Shopping list for this chapter
The basics
Oil and water don't mix. An emulsion is a mixture of the two that stays together, and egg yolk is the classic emulsifier: it contains lecithin, which grabs on to both oil and water. Mayonnaise is simply yolk, a little acid and oil, whisked until the oil breaks into tiny droplets suspended in the yolk.
- Everything at room temperature. A cold yolk or cold oil makes it harder to emulsify.
- Start with a drop at a time. For the first quarter of the oil, add it drop by drop while whisking constantly. Once the mixture thickens you can pour in a thin stream.
- Mustard helps. A teaspoon of Dijon mustard is also an emulsifier and gives a safety margin.
- Acid: lemon juice or vinegar adds flavour and loosens the mixture. Add a little at the start and the rest at the end, to taste.
- Oil: a light-tasting oil (sunflower, rapeseed or groundnut) lets the egg and lemon come through. Extra-virgin olive oil on its own can taste bitter in mayonnaise, so blend it with a lighter oil.
- Steady the bowl: stand it on a damp cloth so it doesn't slide while you whisk.
Raw egg
Fresh mayonnaise is made with raw egg. Use Lion-marked eggs, and use pasteurised liquid egg yolk (sold in cartons) if you are cooking for anyone pregnant, elderly, very young or unwell. Keep homemade mayonnaise in the fridge and use it within 3 days.
Try it
Level 1 · By hand
Mayonnaise by hand
The slow way, and the best way to feel how an emulsion forms. It takes some arm work.
Ingredients (4 portions)
- 1 medium egg yolk, at room temperature
- 1 tsp Dijon mustard
- 150 ml sunflower or light rapeseed oil
- 2 tsp lemon juice, or white wine vinegar
- Pinch of salt
- Put the yolk, mustard, salt and half the lemon juice in a bowl and whisk for 30 seconds.
- Whisking all the time, add the oil a few drops at a time. After about 6 teaspoons, the mixture should be thick and look like pale butter.
- Now pour the rest of the oil in a thin, steady stream, still whisking.
- Stir in the rest of the lemon juice and taste. Add more salt or lemon if it needs it. If it is too thick, whisk in a teaspoon of warm water.
Level 1 · Quicker
Stick-blender mayonnaise
The reliable shortcut. A whole egg, everything in one tall jug, and a stick blender. It works because all the ingredients are right next to the blades.
Ingredients (6 portions)
- 1 medium egg, at room temperature
- 1 tsp Dijon mustard
- 1 tbsp lemon juice or white wine vinegar
- 200 ml sunflower or light rapeseed oil
- Pinch of salt
- Put everything in a tall, narrow jug that just fits the head of the stick blender, with the egg going in first and the oil on top.
- Put the blender on the bottom of the jug, switch it on and don't move it for 15 seconds, while the mayonnaise forms at the base.
- Slowly tilt and lift the blender to pull the rest of the oil down into it. The whole job takes about a minute.
- Taste, and add salt or lemon if needed.
A lighter swap
For everyday sandwiches, stir 1 part mayonnaise into 1 part thick Greek yoghurt. You keep much of the flavour for half the fat.
Level 2 · Flavoured
Aioli
Mayonnaise's garlicky cousin, good with chips, grilled fish, boiled eggs and raw vegetables.
Ingredients (4 portions)
- 1 batch hand-made mayonnaise (above), made with half sunflower and half extra-virgin olive oil
- 2 garlic cloves, crushed to a paste with a pinch of salt
- 1 tsp lemon juice, to taste
- Make the mayonnaise by hand or with the stick blender, using half extra-virgin olive oil and half sunflower oil.
- Stir in the garlic paste and lemon juice. Taste and add more garlic if you like.
- Rest in the fridge for 30 minutes so the flavour develops.
Level 2 · Sauce
Tartare sauce
Mayonnaise with chopped pickles and herbs. It's the classic with fish, and much better home-made.
Ingredients (4 portions)
- 4 tbsp mayonnaise (above), or half mayonnaise and half Greek yoghurt
- 2 gherkins, finely chopped
- 1 tbsp capers, rinsed and chopped
- 1 tbsp chopped fresh parsley
- 1 tsp lemon juice
- Mix everything together in a small bowl and taste.
- Chill for 15 minutes. Keeps for 2 days in the fridge.
Level 3 · Dressing
Caesar-style dressing and salad
A creamy dressing built on mayonnaise, with crisp salad and homemade croutons. A little Parmesan goes a long way.
Ingredients (2 portions)
- 3 tbsp mayonnaise (above)
- 2 tbsp finely grated Parmesan, plus a little to serve
- 1 tsp lemon juice
- ½ tsp Worcestershire sauce (contains anchovy)
- 1 small garlic clove, crushed
- 1 tbsp cold water
- 1 cos or romaine lettuce
- 2 slices day-old bread, cubed
- 1 tsp olive oil
- Heat the oven to 180°C fan (200°C conventional, gas 6). Toss the bread cubes with the oil and bake on a tray for 8 to 10 minutes, until golden and crisp.
- Whisk the mayonnaise, Parmesan, lemon juice, Worcestershire sauce and garlic. Add the water to make a pouring consistency.
- Tear the lettuce into a bowl, toss with the dressing and top with the croutons and a little more Parmesan.
Make it a meal
Add a soft-boiled egg (see Cooking Skills: Eggs 1, chapter 2) or sliced cooked chicken.
Experiments
Experiment
Oil slowly or all at once
See an emulsion split, on purpose.
- Make two half batches of hand-made mayonnaise (1 yolk, 100 ml oil). In one, add the oil drop by drop at the start. In the other, pour a quarter of the oil in at once.
- Whisk both for the same time.
Look for: The slow batch thickens and holds. The fast batch usually looks like thin, oily yellow liquid: it has split. That's the failure you will learn to rescue.
Experiment
Lemon or vinegar
Which acid do you prefer?
- Make two small batches of stick-blender mayonnaise, one with lemon juice and one with white wine vinegar. Use the same amounts.
- Taste each on a boiled potato or a teaspoon.
Look for: Lemon is fresh and fruity, vinegar is sharper and more savoury. Try cider vinegar and lime juice too.
Experiment
Rescue a split mayonnaise
Don't throw it away.
- Take the split mayonnaise from the first experiment. In a clean bowl, whisk a fresh yolk and a teaspoon of mustard.
- Add the split mixture a few drops at a time to the new yolk, whisking, until it comes together. Then pour more steadily.
Look for: A smooth, thick sauce again, with a little more volume than before. A teaspoon of warm water can also bring a split sauce back.
Tasting notes
| Item | Method | What I saw | What I thought | Will I do it again? |
|---|---|---|---|---|
| Mayonnaise by hand | ||||
| Stick-blender mayonnaise | ||||
| Aioli | ||||
| Tartare sauce | ||||
| Caesar-style dressing | ||||
| Slow vs fast oil | ||||
| Lemon vs vinegar | ||||
| Rescued mayonnaise |
Troubleshooting
| Problem | Likely cause | What to do |
|---|---|---|
| Mayonnaise split (oily and thin) | Oil added too fast, or ingredients too cold | Start again with a fresh yolk and add the split mixture slowly |
| Too thick | Too much oil for the yolk | Whisk in a teaspoon of warm water or lemon juice |
| Too thin | Not enough oil, or the emulsion is just forming | Keep adding oil slowly while whisking |
| Bitter taste | Extra-virgin olive oil used alone | Blend with sunflower or rapeseed oil |
| Stick-blender mayo won't thicken | Jug too wide, or you moved the blender too early | Use a narrow jug and keep the blender on the bottom for 15 seconds |
| Greasy, heavy flavour | Too much oil | Add more lemon, or mix with Greek yoghurt |
| Tastes flat | Not enough salt or acid | Season in small stages, tasting each time |
Food safety: raw-egg sauces
Mayonnaise, aioli, tartare and Caesar dressing all contain raw egg. Use Lion eggs, keep sauces in the fridge, make them in a clean bowl, and throw them away after 3 days. Don't serve them to anyone vulnerable unless you have used pasteurised egg yolk or a shop-bought mayonnaise.
Checkpoint: can you do this now?
- I know what an emulsion is and why egg yolk makes one.
- I can make mayonnaise by hand and with a stick blender.
- I can rescue a split mayonnaise.
- I can flavour a base mayonnaise into aioli, tartare and a dressing.
- I know how long homemade mayonnaise lasts and who shouldn't eat it.
Next chapter
Cooking Skills: Eggs 2, chapter 8 is Hollandaise: a warm emulsion with butter instead of oil, and the one that splits most easily. Eggs Benedict is the reward.