The Big Brew Potion is classified as a rare potion which can be found and bought in the Potion Shop. It is located next to the Fly-A-Pet Potion and Ride-A-Pet Potion and can temporarily increase the size of the pet it is fed to for 10 minutes. The Big Brew Potion was released to Adopt Me! with the Magic Update on January 18th, 2020.
The Big Brew Potion features a potion with a pastel blue liquid inside the circular glass container. It has a brown stopper to close the lid.