Why You Should Add Gelatin To Homemade French Onion Soup

Homemade French onion soup is one of those things that just takes time. The onions take time to caramelize, the stock takes time to develop a deep flavor, and the cheese takes time to melt into the signature bubbly topping. You might be tempted to speed up the process by using store-bought stock, but if you do, make sure to add a few packets of powdered gelatin to it.

One sign of a quality homemade stock is its consistency once chilled: It should jiggle like Jell-O. When you make homemade stock with chicken bones, the boiling process pulls out the collagen from the bones, which creates the gel. The more gelled the stock, the more rich, unctuous, and flavorful a soup you can craft. 

The problem is that gelatin is often removed from store-bought commercial stock, so it doesn't fully solidify before it's purchased and used. But you can add in some powdered gelatin and easily achieve the same results: a beautifully fortified stock. 

To truly achieve the same mouthfeel as homemade stock, opt for powdered gelatin over the thin sheets or leaves that are also sold in stores. The powder is able to more easily distribute in the stock mixture compared to the gelatin leaves, which are better suited for making things like jelly.

There is a certain method to follow to best incorporate the gelatin into the stock, and it involves blooming the gelatin first. Blooming, or hydrating, gelatin powder in cold water first before adding it to the stock prevents it from clumping together. Once you've bloomed the gelatin, add the mixture to the stock and bring it to a simmer on the stove or heat it in the microwave to fully incorporate. Another method is to bloom the powdered gelatin directly in the stock when cold, and then heat it gradually once it's hydrated.

You've also got to pay attention to ratios when adding powdered gelatin to store-bought stock. Check the instructions on the box, but in general, one and a half teaspoons per cup of stock is sufficient for French onion soup. Any more and you run the risk of your stock solidifying.