Streams 
Streams are intermediate products of a recipe that arise and are used up again during the process. A stream is produced on a process stage (output stream) and is used up again on at least one other process stage (input stream).
Streams are only available within the recipe version in which they are created.
Prerequisites
In Customizing for the recipe, you have specified that recipes of this recipe type can contain streams (see Recipe Type).
Features
If you assign a recipe input item to a process stage, the system automatically creates an output stream and assigns the item number and the description text of the stage to it. You can then process this stream and use it on a different stage as input stream.
You can assign to an output stream a specification that can only be used for exactly this output stream, in other words, the specification can only be used once within each recipe version for an alternative recipe, and not outside of the alternative recipe.
Note
When you copy a recipe that contains specifications for output streams, the system automatically creates new specifications.
If the component type of the output stream causes an explosion stop, you must assign a specification so that the system considers this formula item in the calculation.
You cannot assign a material or specification to an input stream, the system uses the corresponding data from the associated output stream.
For a recipe with streams, the system always displays the Process view, even if the recipe type does not allow a process. You can process the process stages there.
Depending on your authorizations, you can only use certain functions. For more information, see Different Authorizations for Formula Developers and Process Developers.