All that is known about the making of Veritaserum is that it takes one lunar phase (about 28 days) to brew. If brewed correctly it should be clear and orderless like water. Veritaserum is used for making the drinker tell the truth.
"Three drops of this and even You-Know-Who himself would spill out his innermost secrets." —Severus Snape threatening Harry Potter with Veritaserum.