Beer Forum

This claim made during the Aeration show seems to imply that any foaming of beer can reduce head. Does this mead that shaking a carboy to rouse yeast or shaking a keg to quickly force carbonate will also reduce head retention? Has anyone even tested this back to back with a split batch?

Thanks,

I did the shaking thing when I dry hopped my Green Flash West Coast IPA, and the head on that was like shaving cream, with a nice lacing right down to the bottom of the glass. I know one beer isn't a great sampling, but I say no problems.

I just dont buy that shaking will kill the head retention enough to even be worried about. If that were something to worry about then every commercial beer that is shipped around the world would have head loss since they are rattled around on planes, boats, trucks shopping carts etc...

It is a laughable suggestion, at best. Surely if shaking your beer killed head retention, it would be common knowledge. Lots of people shake carboys to aerate them, or kegs to speed-up carbonation. Besides, what chemical reaction might occur by shaking that would change the nature of head-forming proteins irreversibly? Silly comment.

Some guy on another board did a good test of this, and disproved the absurd idea (see post #2):
http://www.homebrewtalk.com/f128/lost-foam-125225/

Yea, there was some confusing info on this show. Certainly some that contradicts my experimentation and also some might say, common brewing knowledge.

Rather than really get into a debate, I wonder if JZ, JP or anyone else for that matter, could point me to some info regarding the statement about "proteins are only formed once and then destroyed for good". To my knowledge, "bubbling" or aerating does not *form* proteins. The proteins are already there, and I don't see how bubbles could destroy them, but hey, I am no chemist, so bring on the info!

Thanks!
Michael

I don't think we said that proteins are formed, but rather when head is formed, that certain proteins get used up in the process. If you don't believe me, you might instead believe Dr. Charles Bamforth. He was on Brew Strong a couple times and I believe he mentions it during one of the shows. Also, he has written a lot on head formation and retention. Here is a link to something you can read for free:

http://www.scientificsocieties.org/jib/ ... 06-269.pdf

What happens is that to form the bubbles, some of the proteins involved need to unfold, which is non-reversible in this case.

As for shaking, I think when we were talking about this, we were just comparing the relative merits of methods and just listing off anything we could think of. It isn't something to worry about. You'd have to shake the shit out of something for a very long time to see any difference in your beer. However, just about any foaming will use up these proteins when bubbles form at the surface. I don't think people need to worry too much about it. Aerating with an air stone should show this effect faster, but again, it would take excessively long aeration times to have a visible impact. You don't need to aerate more than 10 minutes in most cases. Foaming away for an hour is just a waste.

If you believe me now, maybe you could follow up everywhere else you posted this question.

I guess I can keep shaking my carboy then and not worry about it, since I'm not ready to complicate things much more right now. I'll invest in precise temperature control before I worry about aeration.

Thanks Jamil!

At 20:06 you state "head forming proteins are only formed once...". So perhaps you meant it differently than it came out. No worries. The Bamforth link is very interesting! I don't see where it exactly backs up your statements, but interesting nonetheless.

Based on further research, it seems like there's varying opinions on this topic. Worst case would seem to indicate that yes, the head-forming proteins may be able to "unfold" only once, but there are so many present you'd have to bubble the hell out of a beer to see any degradation.

Lots of threads on it over at homebrewtalk.com.

I assume you're referring to one of the other posts regarding "follow up post everywhere else you posted this question", as I've only posted it here.

I might add that this isn't a case of "if you believe me now", simply a scientific discussion of a theory and asking for references. Please don't take it personally. I appreciate your help!

Michael