Power Source Question

Ok so I am starting an e-brewery build and will need 240v and 30 amp service to my garage. Is my thinking right that I need to replace my regular 240 breaker with a 2 pole 50 amp gfci (or 30 amp but the 50 amp is cheaper)

You will need a breaker sized to the feed wire. If you run 10 guage, you dont want to be running a 50 amp breaker. I would consider running a 50amp with correct wire to your garage, and then a 30gfci out of another panel to your setup. Then you can have a bit extra for lighting, etc.
Otherwise you would be safer using a breaker rated per manufacturers recommendations, while also using correct wire.

Thanks for the info, I purchased a 30 amp.