Alternative Method for Harvesting Yeast Using Blow-Off Tube

I just had an idea for a "new" method of harvesting yeast. While I am sure people have done this in some way, at some point in history, I wanted your opinions.

When fermenting a brew, I usually use a blow-off tube. Said tube runs down into a 1/2 gallon carboy full of star-san (the carboy lid has a hole for the hose and two very small holes to vent CO2). I just had the idea of filling this growler halfway with aerated starter wort with the blow-off tube submerged. As yeast and kreusen blow out of the fermenter, it should inoculate the starter wort and start fermenting, at which point the starter-carboy will be moved to the stir-plate and swapped out for a normal sanitizer carboy.

Normally I would pitch a starter before brew-day, use 95% of the slurry for the brew, and re-pitch the remaining 5% into a starter, so I can cultivate more yeast and freeze it in glycol. With my most recent batch, I purchased Imperial's B44 Whiteout and pitched the whole starter slurry into the brew, so I am hoping to harvest some yeast while it is still young and vigorous, rather than washing the yeast cake.

Any thoughts on this? I know people top-crop, and this is basically just a closed-system way of doing that, but I would love to hear what you think.

 

I might not totally understand your process, but, when I started using a blowoff tube it was because I had an explosive fermentation. Since that time, I rarely have any wort/beer in the blowoff tube. So in my case, I can’t count on getting any yeast to inoculate the starter.

 

I usually ferment 5.5 Gallons in a 6.5 gallon bucket so I usually have at least some Kreusen coming through the tube. I am not sure, but I am suspicious that even without visible blow off there will still be a few yeast cells making their way over. I see what you are saying though. This would probably work better with top-cropping strains that ferment aggressively.

 

Are u worried about something else inoculating your blowoff wort?

 

You have all made good points. it's probably safer to just scoop some yeast foam out of the fermenter.