Kinda looks like I'm doing the right thing...I don't weight the hop bags but I do swirl the fermenter a couple times a day.
It's the time Denny, not the stirring that's the real eye opener here. The stirring is being proposed as an even better/faster way of extraction in a commercial setting.....we don't have or even want the ability to continually agitate in a homebrew situ. Look at the graphs on page 40 & 41. After a day, you're actually decreasing your aroma compounds. It's really some pretty unexpected results.
i hesitate to read too much into this. I have not read it as carefully as I want to yet, but here are some initial impressions.
For Figures 7 and 8 - there are no error bars. This looks like a single experiment. The final (4th) points are also too far from the next (3rd) one - what appears to be a downward trend here could simply be a blip in the data and it could increase after 24 hours. If there were additional data in between that showed the same thing it is potentially more interesting. We also don't know if it is actually the slow and steady decline shown or if it declines sharply and is steady to the final point. Another unanswered question - how much of the decline could be attributed to evaporation of the oil? If it is simply the linalool filling the headspace, perhaps not seen in the others because they have a higher evaporation temperature, then the real thing to do is minimize headspace during dry hopping.
Another issue - compare Figure 5 to Figure 8A - both have linalool concentration at 24 hours around 0.2 ppm. Now compare Figure 6 to Figure 7A - both have myrcene concentrations at 24 hours, but one is around 0.1 ppm and the other is around 0.4 ppm, four times higher. Why the discrepancy?
They did at least some of these experiments pretty warm and with constant stirring - if you recirculate before you blow off the yeast that creates it's own problems and will affect dry hopping. If you do it after, you need to crash/chill and blow off the yeast, heat and recirculate the beer to dry hop, then chill for carbonation and packaging. With the energy and time required to heat and chill large batches of beer, will there really be a savings? I don't know.
It's really interesting stuff and I need to do a more thorough read through. I'm not sure it will have a practical effect on anything in a brewery. As usual, I want more data