BM45 - Maybe a pesky yeast
- Published: Tuesday, 10 December 2013 00:55
- Written by David DeCiero
The Malolactic fermentation is chugging along, but I noticed the other day that the Merlot was moving much faster than the Cabernet Franc. I went back and checked my notes from last year and found the same thing to be true. So, I decided to investigate why this was the case.
I thought about a few of the potential differences before I set forth to discover which one was presumably causing the slowness in the fermentation. Since I treat the musts for both of the grape varieties exactly trhe same in terms of crushing and destemming. At the fermenter, they both got an initial dose of 25 ppm. I do, of course, start with two different grapes, Merlot and Cabernet Franc. Another difference is that the Merlot is inoculated with BDX and the Cabernet Franc with BM45. The BDX does complete sooner than the BM45, but it is only by 1 day. I inoculate with the same VP41 bacteria , so nothing there. I was really only looking at the starting grape and the yeast.
I started looking into the yeasts since that was the only plausible variable. I had read many years ago that different yeasts had different levels of SO2 production, which could impact MLB activity. It turns out that BM45 (and BM4x4) have the same higher level of SO2 production than BDX. There was even a recent areticle in Winemaker about co-inoculation that mentioned that BM45 was not a good candidate due to its SO2 production. So, I think I found my culprit as to why the MLB activity is slower in the Cabernet Franc that used BM45. Something to think about for next year, maybe BM45 is a pesky yeast after all.