Recombining split fermentation

[archthered]

I have a monstrous, 1.118 o.g. and I still need to add sugar, Russian Imperial Stout fermenting. Even though it was only a 5 gallon batch I split the primary fermentation into two containers of 2.5 gallons each to avoid loss from blow off due to a highly volatile fermentation. The original plan was to recombine the two batches after fermentation had stopped, secondary in a fresh vessel, and add oak. I recently had another idea and I would like feedback on if there are any benefits or draw backs to what I am thinking.


My new idea is to combine them before fermentation has stopped, but after it has slowed, and give it a bit more time, then rack to a secondary and oak. When I recombine them I will be sure to include the yeast cake. The purpose of this is primarily to get the yeast to better attenuate, the idea being that by combing them I am basically rousing all the yeast really well giving them a chance to do a bit more before they completely give up. Since this is likely to end up somewhere near 14% I thought this may help me get the gravity to drop a couple more points. Secondly my fermentation chamber can only accommodate two fermentation vessels, currently it is just this stout, since the point of the two vessels was to avoid loss in blow off after that time has passed I see no reason to use up my space and would like to get something else started, that said I don't want to mess the stout up to get something else going. Anyway if any of you have any thoughts about why this is a good idea or a bad one please let me know.


As I said I’m hoping it will help attenuation but will settle for it not causing harm to the stout and just freeing up space.

 

[orionol73]

I made a RIS that came out at 1.111 and I did just what you are describing with the split fermentation. I wanted to avoid the blowoff loss so it was in separate fermenting vessels for the first week to get past the most vigorous part of the fermentation and then I combined it all back together on day 8 or 9 with still lots of fermenting to be done. I did it sooner than later to allow any oxygen introduced to be scavenged by the yeast.

The beer is still conditioning but every sample I have tried has been great and this process seems to have had no ill effect on the beer

 

[archthered]

Thanks, it's good to know that this has been done with no issues