HELP! Stuck ferment: Convertase or Bioferm L

[Kushal]

Has anyone used Convertase or Bioferm L in fermenting beer before, and what was your experience?

We have a beer that has a target terminal of 2.5P that has finished out at 4.2P
There is still a lot of viable yeast in solution and forces with the same yeast and new yeast are both saying this is a fermentability issue, not a yeast issue.

The mash was at 154.4* F (68* C), 2.4* F (1.4*C) above target.

Brewing a compensation tank is probably not an option. While I figure out if it is, I was hoping to get some advice on using enzymes. The fear I have of brewing a compensation tank is that I will be making twice as much beer out of two beers that would be "bad" on their own.

I don't want to dump this tank if it can be salvaged, but it is a large tank and I cannot package it as a different beer.

From what I understand "Convertase" will break down all the dextrins and leave me with a super dry beer. From looking at old threads, it seems some people have used this product successfully by adding very small amounts.
Talking to Kerry (who makes the enzymes) they recommended using "Bioferm L," which is alpha amylase that breaks the 1-4 connection only (rather than convertase breaking the 1-4 and 1-6). I can't find anyone who has used this particular product before. Either way it looks like I may need to cross my fingers and expect to cold crash the beer if we use an enzyme.

Any thoughts or advice would be greatly appreciated.

[ChesterBrew]

What temperature is the FV at? Is there no possibility of increasing its temperature to rouse the yeast?

[chaser]

i've used convertase before. i can't remember the dose rate but use on the bottom end of what they recommend for additions to the fermenter...it's powerful stuff. It's better for adding during yeast pitch on extremely high gravity beers than trying to deal with a stuck fermentation but i've heard of people doing that. Other options, which I assume you've already done is to raise the temp and rouse the yeast repeatedly through the bottom port. Also have had luck harvesting day 2 high krausen wort and pitching it into stuck fermentations.

[Kushal]

Fermentation is at 70*F

There is still a reasonable amount of viable yeast in solution.

As we have run multiple forces with multiple yeasts I feel it is likely not a yeast problem. It is my guess that there are more unfermentable dextrins than desired.

[ATB Consulting]

I know it may not be an option, but if at all possible I recommend blending. Do you have even a small amount of the same beer you could blend just to taste? When I have had a beer out of spec due to a high or low T.G. I would blend with another beer. The reason behind this technique was to ensure consistency in flavor which we used a blind tasting panel to verify that the beer was indeed up to our standards. Thankfully, this was an easy fix due to the volume of similar beer normally produced.