We have in the previous chapters identified different types of the raw materials and products that can ensure a transformation from a petroleum-based to a bio-based society. We have discussed how raw materials can be converted to the required end-products. Before we end up with the final purified product, we still need a number of separation and purification steps. We need to select proper separation methods to reduce the cost of the process and ensure the required quality of our product. In this chapter, we will define the key parameters that are necessary to know to identify the relevant processes. This includes feed concentration, particle characteristics, and solvent properties. The chapter will introduce the existing methods for product purification and introduce guidelines for the selection of the best technologies for the separation and purification processes.

Chapter 1 opens the book with a brief global history of distilled liquors, focusing on current debates about their origins and early development and the possible transfers of knowledge that linked major Eurasian societies in ancient times, including Greece, the Middle East, South and Southeast Asia, China, and Mongolia. This allows us to perceive the multiple origins of soju, moving beyond the expected linear causation. A circulation pattern appears throughout Eurasia, at least wherever premodern occurrences of cross-cultural, inter-civilizational exchanges are well documented. A close examination of distillation processes in the Middle East, South Asia, China, and Central Asia reveals that they bear different characteristics with regard to both their ingredients and their distillation methods. However, one cannot overlook the fact that all the distilled liquors in these countries were originally called arak (ʿaraq meaning “sweat” or “perspiration” in Arabic), which suggests a common agent of transference – namely the Mongols. While the Arabs probably developed distilled liquors, including ʿaraq, the Mongols contributed to a mass-produced arak with portable stills and then popularized the word. With this, the chapter ends with an overview of the Mongols’ role in the widespread dissemination of arak-type spirits to different parts of Eurasia, including Korea.