All mayo is practically the same, right? Well, not so fast. Obviously there are the usual variations such as light mayo, vegan mayo, and many other types you can commonly grab right off the shelf at the grocery store. But there’s one variety that’s only available to food service providers: “heavy duty mayonnaise,” sometimes called “extra heavy.”

I’d never heard of this mayo style until I stumbled upon this Reddit thread from 10 years ago (!!!) discussing the stuff. But what is this magical mayo? Heavy duty mayonnaise is your basic mayo, except it’s fortified with extra egg yolks. This results in a thicker condiment that not only serves as a regular spread for items like sandwiches but also has some unique properties for dishes you probably haven’t thought about much.

Food service professionals value heavy duty mayonnaise specifically for applications like tuna, chicken, and egg salad. Because it’s thicker and slightly richer, it has a much better ability to bind ingredients together, especially in bulk quantities. Let’s say you’re making a massive batch of tuna salad for a deli; one of the last things you want is a watery, messy pan after you’ve held it in the refrigerator for a while. Heavy duty mayo helps prevent that from happening.

The above video from Unilever (I promise this article isn’t secretly sponsored) shares the specs of Hellmann’s Extra Heavy, explaining its uses from a chef’s perspective. Not only does it act as a thicker condiment, but the added egg yolks help with browning during the cooking process. If you’re one of those people who likes to use mayo instead of butter on the outside of a grilled cheese sandwich , heavy duty mayo will provide you with a better tool for getting color on your bread.

Super smart washing When you preorder the new Bespoke AI Washer and Dryer, you receive $500 in Samsung credit back. Order one, get $250 credit back. Nice!

Sorry to say this, but us regular folk can’t just pick up a jar of heavy duty mayo at the local grocery store. This type of product is only available in large quantities (think gallon jugs) at restaurant supply shops. I imagine you’re probably not making enormous quantities of chicken salad at home, so using regular Duke’s or Hellmann’s works just fine, and you’re not missing out.

That being said, there are some restaurant supply shops that are open to the public. I’ve found that you can often come in as a guest, but ask the employee up front to make sure that’s okay. (The stress of shopping at a restaurant supply store is a story for another day.)

Next time you’re at the deli, peek over the counter and look in the kitchen. If you see gallon jugs of extra heavy mayo, congratulations! You’ve spotted an interesting little tool of the trade that will surely improve the quality of whatever you’re ordering.