Emulsions and Dressings
Cooking Skills: Sauces 1
Chapter 7 · Emulsions and Dressings
Shopping list for this chapter
The basics
Oil and water do not mix: shake them together and they separate again in seconds. An emulsion is a mixture of the two held together as tiny droplets. In a dressing, an emulsifier such as mustard, honey, yogurt or tahini coats the droplets and stops them joining up again. A temporary emulsion, like a shaken vinaigrette, separates after a while; a stable one, like a mustard or tahini dressing, stays creamy.
A classic vinaigrette is about 3 parts oil to 1 part acid (vinegar or lemon juice). Adjust to taste: a sharper vinegar needs more oil. Mayonnaise and hollandaise are emulsions made with egg yolk, and are covered in Cooking Skills: Eggs 2, chapters 7 and 8. This chapter covers the egg-free ones.
The method
- Start with the acid and the emulsifier (vinegar or lemon with mustard) and whisk them together with salt.
- Add the oil slowly, a few drops at first, whisking all the time, then in a thin stream.
- Taste on a leaf or a piece of potato, not on a spoon, because dressing tastes different on food.
- Adjust: more oil to soften, more acid to sharpen, a pinch of sugar or honey to balance.
- Dress the salad just before serving, a little at a time, so leaves stay crisp.
| Dressing | Emulsifier | Stays together | Goes with |
|---|---|---|---|
| Simple vinaigrette | None (shaken) | A few minutes | Green salad |
| Mustard dressing | Mustard | Several days | Potato salad, leaves |
| Yogurt and herb | Yogurt | A day or two | Chicken, wraps, vegetables |
| Tahini sauce | Tahini | Several days | Falafel, roast vegetables |
Raw garlic: raw garlic in oil should be used the same day, or kept in the fridge for no more than a day or two, because garlic stored in oil at room temperature can grow harmful bacteria (general guidance).
Keeping sauces: cool a sauce quickly in a shallow container within 1 to 2 hours, press cling film onto the surface to stop a skin forming, chill and use within about 2 days. Reheat until steaming hot, stirring. Milk and cream sauces can split when frozen, so freeze other sauces instead.
Try it
A simple vinaigrette
The simplest dressing, shaken in a jar. Use a good oil, and taste on a leaf. Add a spoonful of mustard if you want it to hold together longer.
Ingredients (4 portions)
- 6 tbsp olive or rapeseed oil
- 2 tbsp white wine vinegar, cider vinegar or lemon juice
- 1 tsp Dijon mustard (optional)
- 1 pinch flaked sea salt
- 1 pinch sugar
- Put the vinegar, salt and sugar in a jam jar and stir to dissolve. Add the mustard if using.
- Add the oil, screw on the lid and shake hard for 15 seconds until thick and cloudy.
- Taste on a leaf and adjust with more oil, vinegar or salt.
A mustard dressing
Mustard, a little honey and a slow stream of oil make a creamy dressing that stays together for days in the fridge. It is lovely over warm new potatoes or a crisp green salad.
Ingredients (4 portions)
- 1 tbsp Dijon mustard
- 1 tsp honey
- 2 tbsp cider vinegar or lemon juice
- 6 tbsp rapeseed or olive oil
- 1 tbsp cold water
- 1 pinch flaked sea salt
- Whisk the mustard, honey, vinegar and salt in a bowl set on a damp cloth so it doesn't slide.
- Add the oil a few drops at a time, whisking constantly, then in a thin stream as it thickens.
- Whisk in the water to loosen, taste, and adjust. Keep in a jar in the fridge for up to about 5 days.
Keeping sauces: cool a sauce quickly in a shallow container within 1 to 2 hours, press cling film onto the surface to stop a skin forming, chill and use within about 2 days. Reheat until steaming hot, stirring. Milk and cream sauces can split when frozen, so freeze other sauces instead.
A yogurt and herb dressing
Yogurt makes a light, tangy, creamy dressing without much oil. It is a good dip, a sauce for grilled chicken, or a dressing for a crunchy salad.
Ingredients (4 portions)
- 150 g natural yogurt
- 1 tbsp olive oil
- 1 tbsp lemon juice
- 2 tbsp chopped parsley, chives or mint
- 1 small garlic clove, grated
- 1 pinch flaked sea salt
- Stir the yogurt, oil, lemon juice and garlic together until smooth.
- Add the herbs and salt and stir. Add a spoonful of water if it is too thick to pour.
- Taste, adjust the lemon and salt, and chill for 15 minutes. Use within 2 days.
Raw garlic: raw garlic is strong; use a small clove and keep the dressing chilled.
A tahini sauce
Tahini is sesame paste, and it does something surprising: stir in cold water and it first seizes into a stiff lump, then loosens into a smooth, creamy sauce. Keep stirring and it comes together. It suits falafel, roast vegetables and grilled meat.
Ingredients (6 portions)
- 4 tbsp tahini
- 3 tbsp lemon juice
- 1 small garlic clove, grated
- 4 tbsp cold water, plus more if needed
- 1 pinch flaked sea salt
- Stir the tahini, lemon juice, garlic and salt together. It will go thick and pale and look as if it has curdled.
- Add the water one tablespoon at a time, stirring well after each. The sauce loosens and turns smooth and creamy.
- Add more water for a pouring sauce, taste, and adjust the lemon and salt.
Experiments
Ratio of oil to acid
Sharp and mild.
- Make three vinaigrettes using 2, 3 and 4 parts oil to 1 part vinegar, and taste each on a leaf.
Look for: 2 to 1 is sharp, 3 to 1 is balanced and 4 to 1 is mild and rich. Choose the ratio that suits your vinegar.
Shaken or whisked
Quick and stable.
- Make a mustard dressing by shaking in a jar and another by slowly whisking. Leave both for 10 minutes.
Look for: The whisked dressing is thicker and holds longer. The shaken one separates sooner but is faster to make.
With and without mustard
The emulsifier.
- Shake two vinaigrettes in jars, one with a teaspoon of mustard and one without, and leave them to stand.
Look for: The one without mustard splits into layers within minutes. The mustard one stays cloudy and creamy far longer.
Rescuing a split dressing
Starting again.
- Take a dressing that has split. In a clean bowl, whisk 1 teaspoon of mustard and slowly whisk the split dressing into it.
Look for: The dressing comes back together. A new emulsifier and slow addition rebuild the droplets.
Tasting notes
| What I tried | Method or amount | What I saw | What I thought | Will I do it again? |
|---|---|---|---|---|
| Simple vinaigrette | ||||
| Mustard dressing | ||||
| Yogurt and herb dressing | ||||
| Tahini sauce | ||||
| Ratio of oil to acid | ||||
| Shaken or whisked | ||||
| With and without mustard | ||||
| Rescuing a split dressing |
Troubleshooting
| Problem | Likely cause | What to do |
|---|---|---|
| Dressing split | Oil added too fast or too much | Whisk the split dressing slowly into a spoonful of mustard in a clean bowl |
| Too sharp | Too much acid | Add more oil, or a pinch of sugar or honey |
| Too oily or bland | Too much oil | Add more vinegar or lemon and a pinch of salt |
| Tahini sauce stiff and lumpy | Not enough water yet | Keep adding cold water a spoonful at a time and stirring |
| Soggy salad | Dressed too early | Dress at the last minute, a little at a time |
| Garlic too harsh | Too much raw garlic | Grate less, or soak the garlic in the lemon juice for 10 minutes first |
Keeping sauces: cool a sauce quickly in a shallow container within 1 to 2 hours, press cling film onto the surface to stop a skin forming, chill and use within about 2 days. Reheat until steaming hot, stirring. Milk and cream sauces can split when frozen, so freeze other sauces instead.
- I know what an emulsion is.
- I can make a vinaigrette with the 3-to-1 ratio.
- I can whisk oil in slowly to make a stable dressing.
- I can use yogurt or tahini as an emulsifier.
- I can rescue a split dressing.