Whiskey particles that have been tested on the International Space Station (ISS) are on their way back home to Earth.

The vials of scotch whiskey were send to the space station in 2011 for an experiment aimed at helping scientists understand how the space's near zero gravity affects the drink's maturation process, according to CNET. Ardbeg, a Scottish distillery that has been around since the 19th century, worked with NASA to conduct the experiment.

"The vials contained a class of compounds known as 'terpenes,'" members of the distillery said. "Ardbeg was invited by US-based space research company NanoRacks LLC to take part in testing these micro organic compounds in a maturation experiment (the interaction of these compounds with charred oak) between normal gravity on Earth and micro-gravity i.e. space."

The whiskey orbited Earth over 15,000 times at 17,227 miles per hour since its launch.

The distillery website states that the whiskey particles were sent in 20 vials with pieces of charred oak that they were treated with when they showed up to the ISS. Instead of containing the liquor itself, the vials only contained microbes that will be used later to brew whiskey, ABC News reported.

"This is indeed a research program to help us understand terpenes, which are the building blocks of flavoring, paints and yes, whiskey- so to us, this is a very solid research project for a consumer-based company," said Jeffrey Mamber, CEO of NanoRocks. "NASA approved the project since terpenes have never been grown in zero-gravity conditions."

The vials are scheduled to land in Kazakhstan on Sept. 12th. Afterwards, they will be shipped to Texas to be compared to similar vials made in Scotland in 2011 to see the effect gravity had on the maturation process.