Will avocado soup turn brown?

Thank you everyone! The plastic wrap worked great, but it is definitely a same day dish. I also added some lemon to the recipe (went better with the other flavors)!

Avocados turn brown for two reasons: oxygenation and enzymatic action.

The pit works only by physically cutting off contact with oxygen, most effective when you're storing half a fruit for later use, rather silly in a bowl of guac, totally worthless in soup. Covering with plastic wrap is far more effective.

Besides refrigeration, two other methods of preventing browning are available in the home kitchen: lowering the pH value (acidification), and adding an antioxidant such as ascorbic acid (AKA vitamin C). Citrus fruit contain both factors; lime is traditional of course, lemon and orange will work as well.

Press a piece of plastic wrap or waxed paper onto the surface, like you would for pudding. The less air exposure the less oxidation.

Save the avocado pit and place it in the container with the soup when you store it. This works for guacamole so hopefully it will work for the soup. It's worth a try at least. Good luck.

The browning process will be slowed down if you add lime or lemon juice to the soup. the acid prevents the oxidation