The old way was no more complicated than introducing 酒麯 (wine koji) into steam-cooked Zhailai rice - known therefore as the Zhailai method, and hoped for the best. Sometimes when things went wrong, then instead of wine, vinegar was the product.
The famed Red-label Taiwan Rice Wine starts out with Penglai Brown Rice (蓬萊糙米), through fermentation, then the crucial step of distillation to obtain up to 11% alcohol (v/v).
In 1927, a new way of making rice wine, the Amylo method, was borrowed from a factory located on the outskirts of Saigon and widely applied for mass production back in Taiwan in 1931.
The Amylo method entails the following: First, mix rice, water and hydrochloric acid, and cook the mixture under high temperature and high pressure until liquefaction. After cooling, add Rhizopus delemar to break down the polysaccharides (i.e., starch) and Saccharomyces (yeast) to produce alcohol, both done at 36C. The fermentation takes only 8-9 days.
Initially, there were Rice Wine Nos 1 to 3 with increasing alcohol content. The 20.5 proof No 2 was re-named 赤標米酒 which became the predecessor of the post-war Red-label Taiwan Rice Wine (see bottle label above). Blending remains a secret; although the formula appears to be [raw rice wine]:[molasses alcohol] = 6:4. At one point in the mid 1940s, the ratio was changed to 4:6 owing to a war time and post-war rice shortage. Increasing the molasses alcohol content further, through blending, then it became 太白酒 (Taibai wine, below), the least expensive, hence very popular rice wine in Taiwan.
The slogans in red were typically seen in the 1950s.