When you scale up your beer brewing batch size, yes you can just multiply your ingredients by how big you want your new batch size is. But you won’t have the same exact finished beer as before. There’ll be some differences.

Example: Your Alcohol Percentage will be different. IBU etc.

Solution: Use beer brewing tools that have Upscaling options in their software. This makes it much easier for you. Example Beersmith has a Scaling-Up part in their software.