BM45 - A pesky yeast?

     I always hear a lot of negativity regarding the yeast strain BM45.  I have heard complaints regarding the production of sulfides and especially slow fermentation.  My experience has been very good with BM45, but then again, it’s not one of those set it and forget it yeast strains.  So, I am sharing my experience with this yeast.

                I originally heard about BM45 from a friend of mine.  I then went to Lallemand’s site to look it up.  It seemed like it would be well suited for my Rhode Island grapes, which will always struggle to ripen fully.  Normally, this might leave the wine with some vegetal aromas, but BM45 seemed like a choice to negate that aspect.  I read up extensively on the strain to make sure that I had a good handle on how to ensure a proper fermentation.  In my readings, I found another strain called BM 4X4, which is BM45 crossed with another strain that ensures proper fermentation.  I could not find it in less than 500 gram bricks, though, so I stuck with BM45.  I figured that with enough careful attention, using BM45 would be OK.  This included making sure to properly rehydrate the yeast, providing sufficient nutrients at the correct time, and punching down to aerate the must.

                In 2011, the Rhode Island Cab Franc grapes came in a bit underripe due to a cool and overcast fall.  This being my first vintage, I was completely stressed out.  My rehydration procedure for BM45 was terrible.  I rehydrated it correctly using the correct water temperature and the correct amounts of water, yeast, and Go Ferm, but dumped the rehydrated yeast at 90 degrees directly into the 60 degree must.  Those yeast must have been shocked!  Anyway, the must took about two days to form a cap, but eventually it did.  I punched down twice a day and added Fermaid K at 1/3 sugar depletion.  It went dry in about 11 days with no issues.

                In 2012, the RI Cab Franc came in more ripe and I was determined to do everything right in my rehydration of the BM45.  I wrote down all the instructions and made sure I would make no mistake.  My rehydration went smoothly, as I slowly added must (1/5 the volume of the rehydration mixture every 15 minutes) to the rehydration mixture.  After 4 cycles, it was within 8 degrees, so I pitched the yeast.  The next morning, there was a cap!  I did the same Fermaid-K addition at 1/3 depletion and punched down twice a day, fully aerating the must.  It went dry in 10 days with no issues.  (The BDX I used on the Merlot took 7 days).  So, it takes a little longer, but I had no problems once I got the right rehydration procedure.

                I am still waiting on the wines to see if BM45 makes that much of a difference in the final product.  I can honestly say, though, that the only true issue with this yeast is the time it takes.  If you do look to complete everything on the same day, this one will be about 2 days later.  I actually prefer this, since I don’t want to press everything in the same day.  It usually ends up being just too much for me in one day.  (Although I do have to clean everything twice!)