Mayonnaise has become so ubiquitously processed that most people can't fathom its being made from scratch. But it can be done. Homemade mayonnaise is tastier, prettier, and more rewarding than store-bought mayonnaise, and once you get the knack of it, making mayonnaise is a snap.
Ingredients
- 3 Egg yolks
- 2 tbsp White wine vinegar
- 2 tbsp Lemon juice
- 2 tbsp Water
- 1/2 tsp Salt
- 1/2 tsp Cayenne pepper (optional)
- 3/2 or 1 1/2 cups Vegetable oil
Steps
Separate the eggs, putting only the yolks in a mixing bowl.
Optional; heat the mixture in a double boiler to a temperature of 150º (65.6C). This will take about 1 minute. Stir constantly and keep a close eye on the temperature. Many people don't bother with heating, but it's essential to minimize the risk offood poisoning (salmonella - seeWarnings). 
Remove the mixture from heat and cool to room temperature. 
Add dry mustard, salt, and cayenne pepper.
Using a whisk or a standing or electric mixer,or a food processor (which works the best), mix the ingredients together.
Slowly, very slowly, teaspoon by teaspoon at first, whisk in an oil that you don't mind tasting (extra virgin olive oil, or peanut or grapeseed,or corn oil, rather than an old, super-cheap container of canola you haven't touched in years).
- If using a stand-alone mixer, pour the oil in drop by drop.
- If using a handheld or electric whisk, it might be helpful to have someone pour for you, or at least to have something holding your mixing bowl steady as you whisk.
Continue adding oil bit by bit until the mayonnaise has reached the proper consistency. This may take up to a half a cup of oil per yolk. If the mayonnaise remains soupy, give it a chance to rest. If in resting the oil and yolk seem to separate, the mayonnaise has broken. See Tips. 
Store mayonnaise sealed in the refrigerator for up to three days. It contains raw eggs, so while it is quite unlikely that keeping it for longer will prove detrimental to your health, you shouldn't tempt fate.Tips
- Make sure that all oil is fully incorporated into the mayonnaise before adding more. If you rush the process, the mayonnaise will "break," and the emulsion will release all its fat to become a useless pile of oil and egg yolk.
- To recover a broken mayonnaise:
- Place another yolk in another bowl and slowly whisk the old into the new.
- Pour some vinegar down the side of the bowl and slowly work the mayonnaise back together, quickly whisking the oil and egg near the vinegar into the vinegar, and then bit by bit whisking the rest of the egg and oil into this. This is more difficult than the other method.
- Place a teaspoon of water into another bowl and then add the broken mayonnaise drop by drop into the water while whisking, just like you added the oil to the egg yolks before. When you have incorporated all of the broken mayonnaise into the water, slowly add the remaining oil (if any) while whisking, just like before
- Use the freshest eggs available (backyard chickens, anyone?), since the lecithin in the egg yolk is what emulsifies the oil, keeping the product smooth and creamy.
- If olive oil is used, the mayonnaise should be used at once. When refrigerated, it will crystallize or solidify. Olive oil makes a very fruity mayonnaise.
- Using a hand-held immersion blender makes this task very easy. Crack the eggs in the container you plan to use to store the mayonnaise--a clean generic salsa jar works perfectly. Add the vinegar, mustard, lemon juice, oil, and seasonings. Plunge the immersion blender into the container, then turn on high. The bottom of the mixture will turn instantly into mayonnaise. While the immersion blender is still running, very slowly lift up the blender to incorporate all of the oil.
- Some grocers and specialty food shops sell "sterile" (free of food-borne bacteria), pre-separated egg whites and yolks.
- To ensure you are adding the oil slowly enough, put the oil into a "squeeze bottle" (like those used for mustard or ketchup, with a narrow nozzle) and squeeze it from that into the mixture. As a guideline to tell if you're doing it slowly enough, it should take at least a minute to add all the oil this way.
- For a healthier alternative, try egg white mayonnaise.
- Using organic, free-range eggs reduces (but does not eliminate) the likelihood of salmonella poisoning. This is because the more space the chickens have, the lower the chances of salmonella contamination.[1]
Warnings
- Because you are using raw egg yolk, care should be taken to avoid food poisoning fromSalmonella. Don't alter the proportions of ingredients unless they are listed as optional, because the acidity is there for a reason--food safety. The recipe presented here is based on U.S. Food and Drug Administration guidelines (see External Links).
- Pregnant women are advised not to eat 'real' mayonnaise due to the aforementionedSalmonella risk from the raw eggs.
