Sorry to disappoint but Soju is haram. Anything contains more than 0.5% alcohol is haram to be consumed/eaten/drunk. As I looked on Google and Wikipedia, Soju contains at least 16.5% alcohol.
From Wikipedia (View the full Wikipedia article here):
Soju (/ˈsoʊdʒuː/; from Korean: 소주; 燒酒 [so.dʑu]) is a clear, colorless distilled alcoholic beverage of Korean origin. It is usually consumed neat, and its alcohol content varies from about 16.8% to 53% alcohol by volume (ABV). Most brands of soju are made in South Korea. While soju is traditionally made from the grains of rice, wheat, or barley, modern producers often replace rice with other starches, such as potato and sweet potato. This liquor features in the drinking culture of Korea.
Soju (소주; 燒酒) means "burned liquor", with the first syllable so (소; 燒; "burn") referring to the heat of distillation, and the second syllable ju (주; 酒) referring to "alcoholic drink".
The evidence (dalil) for the prohibition is the hadith narrated by Ummul Mukminin, Saiyidatina Aisyah R. Anha, that Rasulullah Sallallahu Alayhi Wasallam said:
English translation: "All drinks that produce intoxication are Haram (prohibited to drink)."
Sahih al-Bukhari (5236) and Sahih Muslim (2001)
Another hadith. From Jabir RA, that Rasulullah said:
English translation: "When a lot of things are intoxicating, then even a little is haram."
Sunan Abu Daud (3681), Sunan al-Tarmizi (1866) and Sunan Ibn Majah (3393)
A fatwa from Mufti Wilayah Persekutuan Malaysia goes into details about ethanol/alcohol (Original English version here | Malay version here) :
- Each alcoholic beverage contains alcohol. However, not all alcohol is an alcoholic beverage. Alcohol obtained from the process of making alcoholic beverages is prohibited and najis (impure)
- Whereas the alcohol produced through other processes than for making alcoholic beverages is not najis (impure) but prohibited (should not) to be consumed in its original form (pure ethanol) because it is poisonous and lethal.
- Soft drinks that are processed or made not for the purpose of producing liquor and its alcohol content is under 1% v/v, then it is permissible to be consumed.
- While for soft drinks made with the same intention and process of making liquor, whether it contains a lot or a little alcohol, or if its alcohol is distilled, it is prohibited (haram) to be consumed.
- Food or drinks that naturally contain alcohol, for example, fruits, nuts or grains and its extract, or if the alcohol is produced as a by-product of the food or drink-making process is not najis (impure) and is permissible to be consumed.
- Foods or drinks that contain added flavour or colouring that contains alcohol as a stabilizer is permissible if it is not produced from the process of making liquor and the alcohol percentage content in the final product is not more than 0.5%.
- Medicines and fragrances that contain alcohol as its solvent is not najis (impure) and it is permissible if the alcohol is made not through the process of making liquor
The conclusions are:
Soju is haram because:
- It contains more than 0.5% alcohol, as I read from the Wikipedia article.
- It is made with the same intent and methods to make liquor/intoxicant beverage. Soju means "burned liquor".