What is Mayonnaise?

Karyn Maier

Mayonnaise is a condiment made from an emulsion of an acid and a protein, specifically vinegar (or lemon juice) and egg yolks. While mayonnaise is often referred to as a dressing, it is really intended to "dress" sandwiches and not leaf salads. This is different from standard salad dressing, which is usually made from a combination of vinegar and oil, such as olive or vegetable oil. However, mayonnaise may be added to other kinds of salads to lend creaminess, such as salads made from tuna, crab, or pasta.


The fact that mayonnaise is made from two ingredients that generally do not mix well together is what makes it an emulsion. Making an emulsion, also known as a colloid, necessitates a two-step process. First, one ingredient must be added gradually to the other while applying steady mixing. Secondly, the presence of an emulsifier is needed. In the case of mayonnaise, the emulsifier comes from lecithin contained in egg yolks.

A spoonful of mayonnaise.
A spoonful of mayonnaise.

Mayonnaise is the culinary creation of a chef that served under the Duc de Richelieu in the 18th century. The chef had set out to prepare a special feast to celebrate the Duc’s victory over British troops at Port Mahon. One particular dish was to be made from cream and eggs. However, upon finding the supply of cream depleted, the chef used olive oil instead. The result, named Mahonnaise to commemorate the Duc’s successful military campaign, eventually came to be known to modern deli enthusiasts as simply mayo.

An egg, which is used in making mayonnaise.
An egg, which is used in making mayonnaise.

Mayonnaise is produced on a commercial scale and can be found in any grocery store. However, many cooks prefer the fresh taste and texture of homemade mayonnaise. Making mayonnaise from scratch requires a bit of practice since getting the mixture to completely emulsify can be tricky. However, the use of a blender or food processor makes this task much easier. It should be noted that since the eggs are used raw, it’s very important to use fresh eggs to reduce the risk of salmonella contamination. In addition, unused portions should be refrigerated promptly and consumed within three days.

Store-bought mayonnaise, on the other hand, may be stored in the refrigerator for up to six months after opening. There are also a few standards that regulate mayonnaise production and separate it from other common condiments. For instance, a product labeled as ‘real mayonnaise’ should contain 65 percent oil by weight and only use eggs as an emulsifier. The exception is reduced-fat or fat-free versions of mayonnaise, which usually contains modified food starch as the emulsifier.

Raw egg yolks are needed to make mayonnaise.
Raw egg yolks are needed to make mayonnaise.

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Discussion Comments


@Bakersdozen - Anyone who seriously compares ketchup and mayo is in need of culinary training! It's your lucky day, as there are several recipes for eggless mayonnaise available online.

My favorites are those made with sweetened milk, but you can also use tofu for a totally dairy free alternative.

They both work well in dishes usually associated with the regular kind, so you can enjoy potato salad at a picnic, just like everyone else.


It's frustrating that homemade mayonnaise recipe ingredients always list eggs! I know I may sound unreasonable, but for those with allergies or in the high risk salmonella group, it's ultra depressing.

And no, ketchup isn't much of an alternative, so I wish people would stop offering it instead!


@ark1972 - If you are asking about how long unopened store bought mayonnaise will keep, the answer is - it depends.

Some brands contain preservatives which can extend shelf life for a couple of years, others will tell you to use it within a few months.

The date stamped on the jar is the best guide, and remember that this is the final date it should be used by. If you open it for the first time close to the end it may not keep very long, even if stored in the fridge afterwards.


somebody will let me know about Mayo expiration, it can be 12 months or 18 months ?

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