What's the plural form of vegetable rennet? Here's the word you're looking for.
Answer
The noun vegetable rennet can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be vegetable rennet.
However, in more specific contexts, the plural form can also be vegetable rennets e.g. in reference to various types of vegetable rennets
or a collection of vegetable rennets.