Homemade Mayonnaise

Steps

1. Place the egg yolk, lemon juice, dijon mustard, and salt in a tall, narrow container (a wide-mouth mason jar works perfectly). Let the egg yolk settle to the bottom.
2. Insert an immersion blender all the way to the bottom of the container, resting it directly on the egg yolk. Start blending without moving the blender — you will see the mayo begin to form as a white emulsion at the bottom.
3. After about 20 seconds, once you see a solid layer of white mayo has formed at the bottom, slowly begin pulling the immersion blender upward. Move it up in small increments, allowing the oil above to incorporate into the emulsion.
4. Continue lifting the blender slowly over the next 30-60 seconds until you reach the top and all the oil has been incorporated. The entire jar should now be thick, creamy mayonnaise.
5. Taste and adjust seasoning. Add more lemon juice for brightness, more salt to taste, or a pinch of sugar if desired.
6. Transfer to a clean jar if not already in one. Seal and refrigerate immediately.

Why It Works

Mayonnaise is an emulsion — oil droplets suspended in a water-based medium (lemon juice). Egg yolk contains lecithin, a phospholipid that acts as an emulsifier by coating each oil droplet and preventing them from merging back together. The immersion blender technique works by creating the emulsion from the bottom up: the blender first emulsifies the small amount of egg yolk and lemon juice with just a tiny amount of oil, creating a stable base. As you slowly raise the blender, it gradually incorporates more oil into this already-stable emulsion. Dijon mustard contains additional emulsifying compounds (mucilage) that reinforce the emulsion’s stability.

Tips

• Broken mayo fix. If the emulsion breaks (looks curdled or oily), start fresh with a new egg yolk in a clean jar. Slowly drizzle the broken mixture into the new yolk while blending — it will re-emulsify.
• Flavor variations. Add 1 clove of roasted garlic for aioli, or stir in 1 tablespoon of sriracha after blending for spicy mayo. Fresh herbs like dill or basil can be blended in at the end.
• Shelf life. Homemade mayonnaise lasts 5-7 days refrigerated. Unlike commercial mayo, it has no preservatives, so mark the date on the jar and discard after a week.
• Oil choice matters. Extra virgin olive oil makes bitter mayo. Use light olive oil, avocado oil, or a neutral vegetable oil for the best flavor.