Chinese rice wine - follow-up on taste

Back to the previous post on making Chinese rice wine during Sylvia's confinement period, I actually decided to do 2 separate batches in order to test a theory.

The making of Chinese rice wine is positively swarming with all sorts of superstitious beliefs. These range from disallowing menstruating women to make the wine, to having a certain time of the year which you can make it, and even to the phases of the moon when you can make the wine, yada yada. It's a load of bull to me. Be clean, use the best ingredients, and control the fermentation - that's all it takes! I suspect those who failed probably did terribly in the cleanliness aspect. Anyhow, I was curious to know what temperature the "wine cake" yeast did better at. Does it produce off-flavours and fusels under warm temperatures like our regular brewer's yeast? Does it stall at low temperatures? I finally did a side-to-side comparison.




So we made 2 identical batches - same process, same rice-to-wine cake ratio. One of them fermented in my temp-controlled fermentation chamber at 18C, while the other was left in a cool spot under room temperature (that's to mean Singapore's "room temperature", perhaps 29 to 30C). The rate of production of wine was compared, as was the taste.

The findings:

1. Fermenting at warm temperatures yielded wine at a much faster rate - it was almost completely done within 2 weeks, while the other took almost 4 weeks to produce the same amount of wine.
2. Taste-wise, the warm-fermented one was less sweet and had a mild acetic twang to it. 

I suspect fermenting it warmer allows other organisms (who knows what the heck "wine cake" contains .. other bacteria and fungi most likely) to take a hold more quickly, hence producing just a wee bit more off-flavours. Both were however very drinkable and enjoyable, and neither developed an unwanted infection. Also, we know for sure that the yeast strains in "wine cake" can go as low as 18C without stalling.

TL;DR - ferment it cool (18C) if you can afford the time, it makes for a mellower rice wine. But if you're rushing for time, going up to 30C speeds things up a lot more and still yields a very palatable product.