I agree, I thought about that. I expect that it can be some cases when either ingredients or units have spaces. And the problem is that I can't come up with a solid counter example. Something like @coriander{2%small batches}... You can open an issue in a spec repo so people can discuss https://github.com/cooklang/spec.

Maybe using an underscore might make sense? i.e. {2_small batches}?

Having an explicit delimiter allows for whitespace in either amount or unit. I suppose that's the reason. Can't seem to come up with an example for that on the fly though.