I found this article on WineMakerMag this morning:
https://winemakermag.com/wine-wizard/macerating-skin-packs
At the end of the article is a quote from Gail Tufford, who I've corresponded with at Winexpert:
My first thought was that folks on this forum have proven this wrong, but her comment regarding alcohol, flavor, and aromatics is correct, and is corroborated by numerous technical papers. Alcohol stops increasing when sugar is gone, and flavor/aromatics extraction is complete in the first 2 to 5 days of the ferment.
However, she didn't mention tannin, which continues to extract during EM.
I keep in mind that she works for WE, and her POV reflects her focus on the typical kit wine customer base, where producing a tannic wine is not a normal goal. Looking at it from that POV, everything she said makes sense.
https://winemakermag.com/wine-wizard/macerating-skin-packs
At the end of the article is a quote from Gail Tufford, who I've corresponded with at Winexpert:
“There is no benefit to extending the fermentation period of a kit with skins. It is best to rack off of the skins and sediment after 14 days, 17 at the most. The skins will be spent by this point and will offer no further alcohol, flavor, or aromatics to the wine. The lees will start to break down and can give off-flavors if the wine is left on the sediment too long. It is really important to punch the skins down every day during fermentation. Mix them around and squish the skins bag to the sides of the fermenter and give it a good stir to incorporate flavors and tannin into the must. Even though the wine is naturally off-gassing, which offers some protection, there is still a risk of exposing the wine to bacteria if left in the fermenter too long.”
My first thought was that folks on this forum have proven this wrong, but her comment regarding alcohol, flavor, and aromatics is correct, and is corroborated by numerous technical papers. Alcohol stops increasing when sugar is gone, and flavor/aromatics extraction is complete in the first 2 to 5 days of the ferment.
However, she didn't mention tannin, which continues to extract during EM.
I keep in mind that she works for WE, and her POV reflects her focus on the typical kit wine customer base, where producing a tannic wine is not a normal goal. Looking at it from that POV, everything she said makes sense.