Fortification issue

[Milwood]

Hey everyone. I recently started a Black Raspberry wine with some fruit I picked at a friends farm with the intention of making a port wine. After preparing the must as normal (SG 1.10) and innoculating with yeast (ICV-D47) I covered the fermenter and waited for my yeast to do their thing. I was surprised to see that the next morning the yeast seemed to have been fermenting nicely. However, the next day I wasn't seeing any activity at all. The D47 was from last year but had been stored in the freezer so my first thought was that maybe it wasn't viable. I re-innoculated with a fresh packet of Premier Cuvee. I watched as the yeast took off and started to ferment the must rather quickly. I took an SG reading 2 days later and it read 1.040 which, according to my directions, was time to stop the fermentation by the addition of some 153 proof neutral grain spirits. I added almost a full 750mL bottle (maybe 2 oz shy) to approx. 1.25 gallons of juice. Using the Pearson's square I expected the alcohol addition would raise the ABV to about 19%. I figured this would stop the active fermentation but here I am a few days later and the carboys are still bubbling away. Should the addition of this alcohol have stopped the fermentation almost instantly or is it normal to take a few days to kill of the active yeasts? I'm thinking that because I innoculated twice that it may just take a couple days to kill off the yeasts? If anyone has made port wines before I would love to hear if this is normal.

Thanks!

 

[vcasey]

All to often that process just does not work and is very chancy. The easiest way for a home winemaker to make a port type beverage is to let the yeast finish and then use sorbate & kmeta wait a couple of days and then sweeten and fortify. That being said I have done the same thing, but you really have to be careful about the yeast you pick and understand that the best laid plans just don't always work. The D47 was a good choice because the alcohol tolerance is around 15%, Cote des Blancs or Sweet Mead yeast would have been good choices as well. The Premier Cuvee has a tolerance of 18% and is often used to help with a stuck fermentation and it sometimes does not know when to stop. Another method is to let the SG drop to 1010-1030 and add simple syrup to raise the SG a couple of points a few times until the yeast surrender.
I think your D47 was just fine and I'll bet you may have been able to hear the yeast popping (like soda) if you had listened real closely.

 

[robie]

D47 temperature range is 59 to 68F. Could the must have gotten too hot for the yeast to survive?
Have you taken an SG reading lately? Is the SG actually still falling?
If it is not falling, perhaps what you see is just CO2 being expelled.

 

[paubin]

Just let it sit in the carboy and do it's thing. In wines that i have fortified in the past I've noted that even in a very clear wine you will get a lot of sediment dropping out after fortifying. That being said you need to let it bulk age a while anyway. The yeast if not done yet, should be very soon and like Dancer said you could be expelling CO2. The only way to be sure is monitoring the sg. If it does ferment out more than you want then sorbate and f-pack or back sweeten.


Pete