The colourful (and spherical) world of red juice settling

 Heretic: a person holding an opinion at odds with what is generally accepted. (Google Translate)

Galileo and Christopher Columbus, and several other forward thinkers of their eras, were considered heretics when they proclaimed their beliefs that the earth was round and that the sun did not revolve around the earth. While flat-earthers (yes, they exist) were foaming at the mouth and baying for their blood, Galileo and Columbus merrily went forth and gathered scientific and empirical evidence to support their beliefs.

Just like Galileo and Columbus, the people at Laffort like to challenge convention and do things differently. Which is why this article (click here to read it) is right up our alley. When it comes to red wine making, pre-fermentation juice settling is the last thing that comes to mind. So why would one consider doing it?

The article in the link above paints a rather colourful picture of red juice that was settled (pre-fermentation, similar to white and rosé wine) after which the grape skins were added back, and finally fermentation was started. I specifically say ‘colourful’, because a significant increase (and the highest compared to the control wine) in colour as well as tannin content was seen in the finished wine. Other trial variations included a treatment with a white settling enzyme, as well as a treatment with a conventional red wine maceration enzyme, and finally a control without any added enzyme. Very interesting (and even positive) results were seen with both the enzyme treatments, but in this blog I will focus on the settling treatment, seeing that it is different and it had the most impact on colour.  

 The settling of red juice need not be a foreign, or even blasphemous, concept. In fact, both white and red juice settling achieves the same thing. Which is the removal of suspended grape particles. In this trial the settling step involved the crushing of the skins/marcs and then soft pressing. After treatment with a pectolytic enzyme, the must settled for 24 hours at a low temperature. Similarly, the pressed pomace was also kept cool. The clarified must was then racked and the must trapped in the sediment was recovered by centrifugation, after which the pressed pomace was added to the clarified must. Fermentation was then initiated. Yes, maybe a bit of a schlep. But this blog is not about taking it easy. It’s about challenging convention and doing things differently.  

The finished wines were eventually analysed, extensively, most importantly for colour intensity (CI), total anthocyanins, total polyphenol index (TPI), and polymeric anthocyanins (MCPT). And this is where the treatment that included the juice settling step shone, compared to the other treatments. By eliminating pulp material prior to fermentation, the loss of tannins was reduced by reducing a potential tannin black hole. Otherwise put, tannins can bind to pulp. Less pulp means less tannins that are lost and thus more tannins in the finished wine.

Bear in mind that for this trial the most important consideration was the extraction of phenolic compounds from grapes. One could argue that wine made this way (as in the trial) would be “quick to market”, seeing that cold soaking or post-AF skin contact were not considered. In reference to the enzyme treatment modulations of this study, the value of a quality red maceration enzyme must not be underestimated in making good wine, seeing that that it not only drives colour extraction and stability, but also yield, depectinisation, settling, mouthfeel, and aroma. Quite a list of positives. In the spirit of caveat emptor, read here about the excellent work done on enzymes in red wine making by John Moore and his team at the University of Stellenbosch.

And so, I’ve come to the conclusion of this blog. It was a bit longer than usual and hopefully it did not blow your mind too much. Maybe you would like to do a similar trial next year? Let us know.

And just for the record, despite the cover image of this blog and the ‘spherical world’ pun in the title, I do not believe that the earth is flat.

Now, about that moon landing …