Pitching some harvested Belgian Wit yeast into an aged Dubbel

I recently finished brewing a Belgian Witbier and now that the fermentation is complete I have decided to harvest the yeast cake that remained. I was actually considering taking this harvested yeast and placing it in with my Dubbel that has been aging for about 2 months now in a secondary. It is still bubbling pretty crazy after all this time and was wondering if it would be okay to experiment by placing the harvested Belgian Wit yeast in with the Dubbel. I know that generally you should use a similar yeast strain to the beer you are brewing, but thought since they are both Belgian style beers it might not be a big deal. I am welcome to any comments or alternative suggestions.

What are you trying to accomplish?

After 2 months of aging the activity in the air lock is mostly just co2 coming out of solution, not so much yeast activity. Adding a second yeast this far along isn't going to change much. It will add a chance for an infection. If you want to add a second yeast, do it when you bottle. After you rack off the second cake. Then the new yeast will have some food so that it can produce some of it's characteristics. Some times people add a really dry fermenting yeast if the fermentation has stopped before they wanted it to in an attempt to further reduce residual sugar and boost alcohol, but it doesn't sound like that is the case here.

I guess I would have thought that even after 2 months of sitting in a secondary that the bubbling activity would have calmed down. I am afraid that there is still some residual sugars that have not been fermented out. I figured that if I put in some new yeast that would help to eat up the remaining sugar. Originally when I transferred it out of the primary it did not have this level of activity and am concerned that the beer has too many unfermented sugars for some reason.

I'd suggest you take a gravity reading to find out where you're at

after 2 months, your dubbel is no longer fermenting. it is either CO2 coming out of solution, or you have an infection by wild yeast or bacteria (they can digest sugars that brewers yeast can't). have you taken a gravity reading lately? if gravity has dropped in the past month by more than a few points, i'd be concerned. what was your OG and what was the FG when you transferred to secondary?

pitching the witbier yeast into the already-fermented dubbel won't accomplish anything. it's a very inhospitable environment at the moment: there is nothing left for the witbier yeast to eat (dubbel yeast ate it all), there is alcohol and CO2, etc. the witbier will simply fall to the bottom.

WoodlandBrew said:

If you want to add a second yeast, do it when you bottle. After you rack off the second cake. Then the new yeast will have some food so that it can produce some of it's characteristics.

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i doubt that would have much effect. the amount of sugar added during priming is minimal as is the activity (AKA effect) required to consume it. but if you're going to re-yeast anyways because you fear the original yeast isn't active, and you have re-activated the witbier yeast (via a starter) then using a bit of witbier yeast is no worse that any other choice. but between the small amount of yeast that you would add and the small amount of sugar, don't expect much of an impact. don't add a bunch of yeast hoping this will create witbier flavors - yeast alone can't do anything, it needs food.

I will have to take a reading when I get home tonight to check it out.

Well I checked the hydrometer reading and it was 1.012, which is the expected FG. I think the issue was that the corney keg had some soda residue left over that I did not full clean out. So, it really isn't a fermentation issue, but more of a sanitation issue. I decided to take the Dubbel out of the corney keg and placed it into a fermentation bucket. I then waited until my harvested yeast reached room temperature before I pitched the harvested yeast into the fermentation bucket. I know that this is probably something I shouldn't have done, but figured that I had nothing to lose since the Dubbel was way too sweet with the soda residue left in the keg. I guess I am hoping that the yeast will eat up the sugars from the leftover soda. We'll have to see what happens after a week.

If it's at the final gravity, more yeast isn't going to do much unless it is a higher attenuating yeast. 1.012 sounds like a reasonable final gravity, but you aren't going to know for sure until you are able to take readings a couple of days apart at this point. It's common to add a more dry fermenting yeast to fix a stuck fermentation.