Yeah there 100% is and probably always has been.
The yeast strain, the varieties and processing of the barley and hops, the water source, the process etc all make for wildly different products.
So a make that has a distinctive and popular beer will absolutely guard the recipe. This was true at least back through the medieval period, and there are some Belgian beers that still have proprietary recipes that are hundreds of years old
Yeah there 100% is and probably always has been. The yeast strain, the varieties and processing of the barley and hops, the water source, the process etc all make for wildly different products. So a make that has a distinctive and popular beer will absolutely guard the recipe. This was true at least back through the medieval period, and there are some Belgian beers that still have proprietary recipes that are hundreds of years old