About This Site

This is a blog about “beering,” i.e. the process of making beer, reading about beer, analyzing beer, and enjoying beer.  While beering is just a hobby for me, I know what I like, I have fun conducting experiments, and I keep good notes.

Over time, I’ve gravitated toward a “scientific publication” format for these posts, simply because I think it’s effective at communicating the most information with the least number of words.  With recent posts being a bit long, I don’t want to drag the reader down with any unnecessary words, which unfortunately also leaves out a bit (or all??) of the fun.  Behind all of the dull words and boring equations, I’m really interested in the high-level conclusions, and I hope you also find the overall topics interesting.  Feel free to skip over any details that don’t interest you; they’re there in order to provide a solid foundation for the conclusions.

This blog is not meant to be a regularly-updated site, but a place where I can share, every so often, some of my results.  I edit old posts with new data, so that the posts on a particular topic are always up to date with the best information I have.

Both “beering” and “alchemy overlord” are meant to be tongue-in-cheek names.  I don’t want to be overly serious about something as enjoyable as beer.

This site has advertising that is administered by WordPress.  Although I have no control over this advertising (it being the price I pay for free hosting), if you have any questions or concerns about it, please let me know.

If you’d like to contact me for any reason, send an e-mail to the name associated with this blog (no spaces) at yahοο.

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6 thoughts on “About This Site

  1. VS

    Hi, I have a question on the mIBU calculator, in the option:
    ” cool with immersion chiller to X°C; hold this temperature during hop-stand time”
    This means that you are adding the hops at X°C right? and not immediately at flameout and then doing a cooler hop stand?
    Just want to make sure the calculation is in line with what im doing.

    Reply
    1. Alchemy Overlord Post author

      Hi, thanks for your question! This brings up an interesting feature of the calculator. The timing of the hop additions is independent of the wort cooling. So, if you use the calculator to add hops at 0 minutes (i.e. at flameout) and then cool with an immersion chiller to 80°C, that means that the hops are added to the boiling wort and chilling starts at the same time. If you want to first cool the wort to 80°C and then add hops, a negative hop addition time (relative to flameout) is needed to wait for the wort to reach that temperature. For an exponential decay factor of 0.15 it takes about 2 minutes to cool the wort to 80°C, and so you should enter a steep time of -2.0 for that hop addition. (With boiling at 100°C, a base temperature of 20°C, and a decay factor of 0.15, temperature = 80*exp(-0.15*time)+20, and so time = ln((temperature-20)/80)/-0.15. If you know the target temperature, you can compute the time to reach that temperature, or vice versa.)

      Reply
  2. MBBoesen

    I really enjoyed your recent article in BYO on IBU measurement. I have a pretty fundamental issue that I can’t seen to get ananswer on. It is well recognized that IBUs drop materially during fermentation, but it is acknowleged that beer recipes use formulas to estimate IBUs prior to fermentation. How did you reconcile the disconnect between the IBUs in wort (recipes / formulas) vs finished beer (lab measurement)? Would you know if the IBUs listed in the BJCP style guidelines based on spectrometer measurement or formulaic?

    Reply
    1. Alchemy Overlord Post author

      These are great questions! I’ve heard conflicting claims about whether the Tinseth model was based on wort or beer, so I emailed Prof. Glenn Tinseth just now and asked him. He said that he measured wort samples. So there does seem to be a difference between the Tinseth model predictions and IBUs in beer. This might explain why, on the test data I have (Chart 2 in the BYO article), the Tinseth model over-estimates IBUs in finished beer, and the discrepancy becomes larger for higher-IBU beers. The Rager formula yields roughly similar estimates to the Tinseth formula on my test data, so the Rager formula may also provide estimates of wort IBUs. The Garetz formula seems to underestimate for low-IBU beers and yield reasonable results for high-IBU beers, so Mark Garetz may have based his model on the IBUs in beer. I’ve seen different estimates of how much IBUs are reduced during fermentation, but a factor of 0.85 (a 15% reduction) fits my data well. The SMPH model includes this fermentation factor, and so it has been designed to model the IBUs in finished beer.

      In a discussion on the AHA forums (https://www.homebrewersassociation.org/forum/index.php?topic=6610.0), dmtaylor says “The BJCP guidelines provide ranges from actual laboratory data, not Rager or Tinseth formulas”. In that same thread, David Houseman says that the BJCP IBU numbers are not based on formulas. So the BJCP style guideline IBUs appear to be from measurements of beer.

      Reply
      1. Alchemy Overlord Post author

        Yes, it’s not clear to me why the fermentation-related losses at this brewery (27% to 57%) are higher than other reports I’ve seen (Fix 10% to 20%; Laws (cited by Malowicki) 5% to 17%; Laufer and Brenner (cited by Malowicki) 10%; Spetsig 10% to 15%; Hieronymus 20%; Nielsen 18%). I can think of several possible reasons, but they’re all speculative.

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