Nothing particularly new to report about my beers. I've been pretty content with the way that they've been coming out. I can't wait to build my new mash/lauter tun. I should be starting that one this evening. Hopefully that will help me solve my extract efficiency issue. The only outstanding issue I've had beyond that is achieving satisfactory head retention. Head retention is something I really do not have my head wrapped around. I know there are many oft-cited ways to improve this, e.g. use dextrine malts, try some wheat malt, cut down on adjunct use, don't use dirty glasses, etc. However, only today did I happen across two new potential sources of my problem: 1.) pH. 2.) fermentation temperatures.
I noticed this today. Miller writes, "Check your beer's pH to make sure it is not abnormally low or high. Finished ales should be in the range of 4.0-4.5. " I can't say I'd ever considered that as a source of poor head retention before. I knew that pH could certainly affect mash extract efficiency, but head retention? All the more reason for me to get some litmus paper and start taking notes.
Miller also mentions fermentation temperatures in the same article. He doesn't say much more about how it might affect head retention, though my somewhat-educated guess is that one would be wary of abnormally high temperatures rather than low ones. My thought is that fusel production negatively affects head retention. While I suspect this is true, my reasoning is not exactly flawless. When I think fusels, I recall that they are sometimes referred to as fusel oils. I immediately associted oils with lipids, and lipids with foam inhibition. I'm going to have to look into this further to see if I'm on the right track, but that's what I have off the top of my head.
I feel as though my technical understanding of brewing has been advancing rapidly these past few months. Certainly obtaining copies of Fix's Principles of Brewing Science, Daniels' Designing Great Beers, and Noonan's New Brewing Lager Beer have helped. Even just writing the Technical Tuesday portion of the blog has been helpful. That was the idea from the beginning: to force me to really get the facts straight before writing about them. Hopefully I'm doing an alright job at clarifying some aspects of the hobby - it's a great one.
 Miller, Dave BT - Troubleshooter: Vol. 5, No. 5 (accessed Aug. 1 2007)