How do I create individual fields on a node?
Have a look at my answer to "How to add new data to a predefined list?", which describes what you can do with the Select (or other) module.

In your case, you could use that module also to define 2 fields, which I'd label something like so (or anything else you'd prefer):


Attribute (with values like Material, Color, Year, ...).
Value (with values like Plastic, Red, 2015, ...).


Obviously, if "I" would then want to add like "Taste = Sweet", I'd just have to add "Taste" to the 1st field, and "Sweet" to the 2nd field.

Sweet enough?