The exact dosage of lemon juice to make or make your homemade mayonnaise

Making a successful homemade mayonnaise is a source of pride for any cook, but its creation can sometimes be capricious. If the texture remains liquid or if the emulsion “turns”, the mayonnaise has failed. Most traditional recipes include lemon juice. What is the exact dosage of this acidic liquid and what role does it play in stabilizing the emulsion or catching up with mayonnaise that refuses to set?

Quick answer: For a classic mayonnaise made with an egg yolk, the ideal dosage is one teaspoon (about 5 ml) of fresh lemon juice. Lemon juice provides the water necessary to initiate the suspension of the oil droplets and its acidity modifies the charge of the egg yolk proteins (lecithin), facilitating their role as an emulsifying surfactant. To make up for a failed mayonnaise, whisk a teaspoon of warm lemon juice in the bottom of a clean bowl and add the failed mayonnaise little by little.

The scientific explanation (Level): Colloidal emulsion, surfactants and micelles

Mayonnaise is an oil-in-water (O/W) emulsion. Egg yolk provides natural surfactants, mainly phospholipids (lecithin) and lipoproteins (LDL). These molecules have a hydrophilic head (attracted to water) and a hydrophobic tail (attracted to oil). They position themselves at the interface of the oil droplets to form stabilized micelles, preventing coalescence (the fusion of the oil droplets).

To create an emulsion, there must be a continuous water phase into which to disperse the oil. An egg yolk contains water, but the addition of lemon juice provides an essential mobile aqueous phase. If you run out of water, the oil droplets touch each other and the emulsion collapses. In addition, citric acid lowers the pH of the preparation. This acidic pH positively charges the amino acids in egg yolk proteins, causing them to repel each other. The proteins spread more easily around the oil droplets, which increases the viscosity and strengthens the physical stability of the mayonnaise.

Feedback: Fixing a broken emulsion

One day when I incorporated my oil too quickly, my mayonnaise turned into a mixture of oil floating on coagulated egg yolk: it had completely turned. Instead of throwing everything away, I applied the culinary physics technique. In a clean bowl, I poured 5 ml of fresh lemon juice. I scooped out a spoonful of the failed mayonnaise and whisked it vigorously into the lemon juice. A white, firm emulsion immediately reformed at the bottom of the bowl. I then added the rest of the failed mixture very slowly, while whisking. In less than 2 minutes, my mayonnaise was impeccable, firm and airy, with a pleasant freshness in the mouth brought by the lemon.

Conclusion

Lemon juice is not a simple flavor enhancer in mayonnaise; it is a physical stabilizing agent essential to the very structure of the emulsion. Use it at the right dosage to guarantee the success of your sauces.