In Star Trek (2009), the villain Nero uses Red Matter in order to
Create a singularity at the center of Vulcan, destroying the planet.
This Red Matter was initially created by Spock
in order to create a singularity to destroy the Hobus Supernova.
In both cases it clearly only takes one drop of Red Matter in order to achieve this. Despite this, a significant amount of Red Matter is seen in Spock's ship- much more than was needed simply to
Destroy the Supernova
(Not sure if that needs to be in a spoiler box, but it's a pretty major plot point.)
So, in short, why did Spock manufacture this:
When he only needed one of these?
(I'm looking for an in-universe answer; out of universe I understand that there's no plot without the extra Red Matter)