Rescuing a stuck ferment with a blended batch

[pwizard]

Last weekend I started a 1-gallon batch of Orange Blossom trad (OG 1.135). I used Montrachet yeast, but at the time I forgot it doesn't do well in high gravity musts. The ferment got started, but it was very slow and eventually quit on me at around the 1/3 sugar break (1.090) a few days ago. It's still there as of last night, which is the last time I checked. The Montrachet hasn't dropped yet so it still seems to be active but struggling, even though it should have no problem with the current gravity. It still smells ok (no sulfur) so I'm not sure what the problem is. My PH is probably fine since I added 1.5 tsp of CaCO3 to this when I mixed it up like I do for every trad. I re-hydrated properly and gave it the full TOSNA schedule, so I either got a bad packet of Montrachet or I pushed it too far, I'm not completely sure which.

I just got finished with mixing up another 1 gallon batch of Orange Blossom, this time with K1V-116 (OG 1.120). Once that gets going I'll give it the first two TOSNA feedings, and wait for it to reach 1.090. Then I'll treat the K1V batch like a really big starter and blend the two batches together equally, and give both containers the last two feedings. Since they're the same gravity at that point, I'm replacing about 50% of the volume, and the K1V is the stronger yeast, it shouldn't have a problem finishing both. The first batch seems ok as far as cleanliness goes but I chose K1V because it will kill off the Montrachet yeast and anything else that might have gotten into the first batch. Sound like a plan?

 

[Squatchy]

Nothing say for sure that K1V will kill of the Montrachet. What is the kill factor for Montrachet? DO you know? Even if it's sensitive doesn't promise that a killer strain will always kill it off. Too many people believe this, even though it's not entirely true. I didn't know the difference until I started studying manuals from different Colledge programs about wine fermentation.

 

[pwizard]

So does the K1V actually kill the other yeast or just out-compete it? According to Scott Labs, the Montrachet is a sensitive yeast:

http://www.scottlabsltd.com/product/montrachet-davis-522-vi-a-dry-yeast/

I've never had this kind of stuck ferment before, so I'm not completely sure what side effects happen when two yeast strains fight it out in the same batch (fusels, off-flavors, etc).

 

[Squatchy]

I haven't ever had a batch stick. So I can't speak from experience. I would follow the " restart" protocol in the handbook.

 

[Medsen Fey]

K1V is NOT a good yeast to use for restarts.
You’ll be much better served by lallemand 43 (formerly uvaferm 43), EC-1118, DV10, or QA23.

Please be sure to check the ph. If it is below 3.3, adjust it upward.
It is usually a good idea to treat with a dose of yeast hulls as this can bind medium chain fatty acids that can be toxic to yeast. Sometimes these steps will unstick a fermentation.

Generally, you want to take your restart yeast and rehydrate with goferm as usual, and then gradually add must from the stalled fermentation doubling the volume each time and letting it get bubbling before the next addition. You probably want at least a pint and then pitch it in. It may take overnight to have it ready.

A good thread on on restarting without acclimating in the patron’s area-
http://www.gotmead.com/forum/showthread.php/20735-Restarting-with-non-acclimated-yeast

 

[pwizard]

We all know airlock activity and bubbles mean nothing (it's been doing that the whole time), but I just took another reading on the Montrachet batch and it is down to 1.070. It may not be truly stuck after all, just really, really slow. I still intend to blend it, since even if the Montrachet keeps going at this pace I doubt it will finish properly. The K1V should have no problem taking this dry, which is what I wanted in the first place.

Unfortunately I've already started the K1V batch so I'll have to use it. I'll keep your advice in mind in case this happens again. However, I'm curious why you say the K1V not well suited for restarts. Scott Labs recommends it for that purpose: http://www.scottlabsltd.com/product/k1-v1116-premium-yeast/

 

[Squatchy]

I'm also curious to see what Medsen says as to why not to use K1V.

 

[Medsen Fey]

The article referenced in the prior link compared K1V with several other yeast, and its performance was the poorest which agrees with what I have experienced in some episodes where I’ve tried to use it for restarts. I’m not saying that it cannot do restarts, but there are much better yeast choices for that situation.