Here’s a clear, by-hand method for making thick, glossy mayonnaise at home, plus some pro tips so it doesn’t split.

Quick Scoop

Homemade mayonnaise is just an emulsion of egg yolk, oil, and an acid (like lemon juice or vinegar) whisked together until thick. It takes about 10 minutes of steady whisking, no blender needed.

Ingredients (Classic Hand-Whisk Mayo)

For about 1 cup of mayonnaise:

  • 1 large egg yolk (room temperature)
  • 1 teaspoon Dijon mustard
  • 1 tablespoon lemon juice or white wine vinegar
  • 1 cup neutral oil (sunflower, grapeseed, canola, or light olive oil)
  • ½ teaspoon fine salt (or to taste)
  • A few teaspoons water (optional, for adjusting thickness)

You can use a whole egg instead of just the yolk for a slightly lighter texture, but yolk-only is traditional and very stable.

Step-by-Step: How to Make Mayonnaise by Hand

1. Set up your bowl

  • Use a medium, heavy bowl that won’t slide around; set it on a damp towel to keep it steady.
  • Make sure your egg yolk is at room temperature; cold ingredients make it harder to emulsify.

2. Make the base

  1. Add to the bowl: egg yolk, Dijon mustard, lemon juice (or vinegar), and salt.
  2. Whisk until smooth and slightly thickened. The mustard helps stabilize the emulsion and adds flavor.

3. Start the emulsion (the crucial slow phase)

  1. Begin adding oil drop by drop while whisking constantly and vigorously.
  2. Don’t rush this part: for the first 2–3 tablespoons, go painfully slow—tiny drips only.
  3. You should see the mixture gradually thicken and turn pale and creamy.

If you add the early oil too fast, the mayo is likely to split.

4. Gradually speed up the oil

  1. Once the mixture is clearly thicker and looks creamy (like loose custard), you can add oil in a thin stream.
  2. Keep whisking nonstop—small circles, steady pace—while you pour with your other hand.
  3. Pause every so often to make sure it’s still thickening; if it looks greasy or separated, stop adding oil and whisk harder until smooth again.

5. Adjust texture and taste

  • If the mayo gets too thick , whisk in a teaspoon or two of water or lemon juice to thin it slightly.
  • Taste and adjust:
    • More salt for savory punch
    • More lemon juice/vinegar for brightness
    • A pinch of sugar if you like it rounder and less sharp

You’ll know it’s ready when it’s glossy, holds soft peaks on the whisk, and is pale yellow to off-white.

6. Store it safely

  • Transfer to a clean jar with a tight lid.
  • Refrigerate and use within about a week; always use a clean spoon when scooping.

What If It Splits? (Rescue Trick)

Sometimes the mayo suddenly goes thin and grainy—that’s a broken emulsion. To fix it:

  1. In a clean bowl, put 1 fresh egg yolk.
  2. Slowly whisk the broken mayo into the new yolk, starting with just a teaspoon at a time.
  3. Once it thickens again, you can continue adding the rest in a thin stream.

This works because you’re giving the fat a fresh water/lecithin “base” to grab onto again.

Variations and Flavor Ideas

Once you have a good basic mayo, you can turn it into lots of sauces:

  • Garlic mayo / aioli-style : Add 1–2 finely grated garlic cloves plus a bit more lemon.
  • Herb mayo : Stir in chopped parsley, chives, tarragon, or dill.
  • Spicy mayo : Whisk in a little chili paste, sriracha, or smoked paprika.

Always add flavorings at the end so they don’t interfere with the initial emulsion.

Little Story-Style Tip

Many people today learn mayo with a blender, but classic French technique has cooks learning it by hand first: egg yolk and mustard in a bowl, oil drip by drip, and a sore whisking arm as proof you did it right. Once you “feel” the emulsion forming—when the mixture suddenly thickens after just a spoonful of oil—you understand what’s happening better than any machine ever shows you. That feel is what makes your next batch almost foolproof.

TL;DR:
Egg yolk + mustard + acid in a bowl, whisk; add oil drop by drop until it thickens, then in a thin stream while whisking; season and adjust with a bit of water or lemon juice if needed.

Information gathered from public forums or data available on the internet and portrayed here.