Hop compounds that leave during fermentation - Recover them?

[PrinceOfThePoint]

I haven't though of it enough as a real engineering problem yet. But significant amounts of hop compounds are removed as exhaust from the
fermentation vessel. While we don't know the exact make-up of the gas mixture, leaving the vessel, we could still try somehow to pass the vapor through a packed column of water or other solvent more appropriate to dissolve the hop compounds. If the water or solvent could absorb the hop oils, it would be relatively simple to return them back to the carboy/vessel/beer whatever by separation. Or even taking the water/solvent that loads the hop compounds and just adding it all back without separating. I wonder...

 

[ajdelange]

When we attempt to recover the essential oils from hops we use an apparatus like the one pictured here:
http://www.pbase.com/agamid/image/132252629
The flask is charged with hops and water. Steam bearing the oils passes up the main tube from the flask to the condenser where both condense and fall back into the vertical tube beneath the condenser. The lighter oil floats on top of the denser condensed water
http://www.pbase.com/agamid/image/132252630
and when there is enough condensed water in the tube it flows back to the flask through the side arm.

In principle you could scale this up with the flask being replaced by the kettle etc. The problem I see here is that you would condense not only the desirable essential oils but the undesirable DMS etc. as well. Perhaps this could be gotten around by terminating condensation at some point before the end of the boil under the presumption that most of the essential oils have been collected. The remaining boil time would allow DMS to be driven off without returning it to the kettle.

 

[brewfun]

significant amounts of hop compounds are removed as exhaust from the fermentation vessel. While we don't know the exact make-up of the gas mixture...

The capture of CO2 and separation of volatiles is a pretty common practice among breweries around the world, including most of the largest US Craft brewers. They produce a lot more CO2 than they need, so at that scale it becomes a revenue stream.

The trouble with the volatiles is that they contain more than just hop aromatics. DMS and other sulfurs are part of the mix. You'd probably want to strip those out somehow.

Fermentation does more to transform hop flavors than just letting a little out with the gasses. Raw hop aromatics are still best infused by dry hopping at the correct time.

 

[PrinceOfThePoint]

Great replies guys, thanks!

 

[ajdelange]

Delighted you liked the reply even though it didn't answer the question you asked!