head retention, boil temp for LPT1 unravelling

[scottlindner]

OK.. I must first admit this is my first uber geek high tech homebrewing discussion. I have been having troubles with head retention of my beers since relocating from a fairly low elevation (280ft MSL) to a fairly high elevation (6700ft MSL). I have been investigating water chemistry differences, fermentation temp differences, and recently elevation differences. This post is mostly focusing on the elevation differences. All that being said.. on with my post.

I have read this article from BYO about the technicals of head retention:
http://***********/component/resource/article/697-getting-good-beer-foam-techniques It notes that LPT1 unravels during the boil which improves head retention. I read these two short articles about LPT1 stability at high temperatures:
http://linkinghub.elsevier.com/retrieve/pii/S0014579300024248
http://www.ncbi.nlm.nih.gov/pubmed/16608238

This got me wondering if stability and unraveling are referring to the same thing, and if my elevation may be causing me issues because my boiling point is 196F/91C but both of these articles refer to LPT1 stability up to 100C. I also noted this detail in the second article, "Unfolding of LTP1 occurred only when heating was conducted in the presence of a reducing agent". What is this reducing agent, and is it something people add to the boil to improve head retention?

My biggest issue to identify is if my relatively low boiling point may be causing me troubles and if there is something I can do to account for it.

Cheers,
Scott

 

[Yooper]

My biggest issue to identify is if my relatively low boiling point may be causing me troubles and if there is something I can do to account for it.

Cheers,
Scott

You know, that's what occurred to me. I'm not sure how to account for it- I mean, boiling is boiling and you can't exactly change the temperature of that boil.

A work-around fix might be to simply add some protein (flaked wheat) or some dextrine malt to your batches. I'm no scientist, but I'm very interested in what others have to say on this issue!

 

[menschmaschine]

The abstract of the last linked article states:

... it was shown that unfolding occurred on wort boiling before fermentation and that the reducing conditions are provided by malt extract.

So, wort and/or wort constituents are essentially reducing agents. Na is a reducing agent as well as Ca and Mg. I doubt a lack of reducing agents are your problem.

This is an interesting problem because, as implied by the articles, LPT1 would be significantly reduced in worts boiled below 100°C... which would decrease foam formation/stability. I don't know how one could compensate for this, short of boiling in a pressurized container. What about pH? Was that mentioned anywhere in the articles?

 

[scottlindner]

You know, that's what occurred to me. I'm not sure how to account for it- I mean, boiling is boiling and you can't exactly change the temperature of that boil.

A work-around fix might be to simply add some protein (flaked wheat) or some dextrine malt to your batches. I'm no scientist, but I'm very interested in what others have to say on this issue!

My understanding from the first link I provided is that simply adding more protein doesn't really work. It's kinda like a common myth.

As for my issue(s) I'm still trying to get smarter to determine what exactly is off. I fully expect water chemistry is my biggest culprit in the changes in my beer since moving here, but I'm trying to understand all affects that may have changed.

Based on the other response I do wonder if I'd need to pressurize my boil. That sure seems excessive. I'm going to talk to some of the local micros to see what they might have done. That's why I'm curious about the temperature that LPT1 unravels. If it will still unravel in the 190-200F range, but more slowly, I would just need to extend my boil.

I plan on a full rolling boil rather than being concerned with HSA. Maybe that will be good enough?

Cheers,
Scott

 

[Yooper]

I'm not sure what you mean about having a full rolling boil- are you not boiling "hard" now? My boil is quite vigorous, and my beer is better for it, I believe. I get crystal clear beer.

 

[willynilly]

Boil hard, boil long (90 mins)... I have seen marked refinement in my finished brews by doing so. Almost no one boils at 100C, as the majority of us are not at sea level. The numerous breweries out in Colorado are making it work, so I am not convinced that the boil and LPT1 are the culprits.

You can only boil so hot and for so long, and you cannot really have a pressurized boil as there will be other issues.

Good on you for doing the research though.

 

[scottlindner]

I'm not sure what you mean about having a full rolling boil- are you not boiling "hard" now? My boil is quite vigorous, and my beer is better for it, I believe. I get crystal clear beer.

Many people are concerned with HSA from a vigorous boil. Now that I live in the Rockies it appears I cannot get away with it anymore and screw the HSA risks. I suspect it's another overstated homebrewing boogeyman.

Scott

 

[Rushis]

So, wort and/or wort constituents are essentially reducing agents. Na is a reducing agent as well as Ca and Mg. I doubt a lack of reducing agents are your problem.

This is an interesting problem because, as implied by the articles, LPT1 would be significantly reduced in worts boiled below 100°C... which would decrease foam formation/stability. I don't know how one could compensate for this, short of boiling in a pressurized container. What about pH? Was that mentioned anywhere in the articles?

Na, Ca and Mg metal are reducing, the cations that are present in wort (Na+, Ca2+ and Mg2+) are not reducing. But I do agree with the assessment, the reducing capacity of the wort should not be an issue. There are plenty of a cysteines and other thiol containing functionalities from the grain that provide reducing equivalent. In addition the wort should be acidic (pH = 5ish), which also facilitates the reduction of the disulfides that are responsible for LPT1s stability.

The FEBS article states that the isoelectronic point from a variety of LPT1s is less than 9 and that the optimal thermal stability was observed at approx. pH=7. Insuring that your wort is slightly acidic should help with the degradation of LPT1s.

Based on the FEBS article, LPT1 begin to denature at 90C but their instrument didn't go above 100C, thereby limiting their ability to determine the exact melting point of the protein.

I don't believe that the difference in elevation (and consequently lower boiling temperature) are significantly reducing your ability to denature LPT1, especially to the point where it detrimentally effects head retention.

What is your mash pH? Is your water extremely hard? Do you have maltsters analysis sheet on your grains to know what the protein content was?

 

[Rip]

Many people are concerned with HSA from a vigorous boil

...Hmm - I've been under the impression that vigorous boiling removes O2 from wert, I can't imagine how boiling would introduce HSA.

http://www.elmhurst.edu/~chm/vchembook/images2/174solublegas.gif

- M

 

[willynilly]

Yes, boiling removes O2, it will not aerate your wort

 

[samc]

I have been investigating water chemistry differences, fermentation temp differences, and recently elevation differences.

Did you look at ingredients? Are you using different base malts, etc.?

 

[Yooper]

...Hmm - I've been under the impression that vigorous boiling removes O2 from wert, I can't imagine how boiling would introduce HSA.

http://www.elmhurst.edu/~chm/vchembook/images2/174solublegas.gif

- M

Yes, boiling removes O2, it will not aerate your wort

I don't really think HSA is a problem, but IF it occurs, boiling will not remove the o2. That's how it occurs- aeration of the mash, preboil, or postboil hot wort (that's what the "hot side" part is about.) I think this it's much of an issue for homebrewers, but it's something to be aware of. I don't splash or pour hot wort unnecessarily. Some info: http://oz.craftbrewer.org/Library/Methods/Other/HSAmash.shtml
http://www.brew-dudes.com/hot-side-aeration/124
http://www.howtobrew.com/section1/chapter6-9-3.html

 

[scottlindner]

...Hmm - I've been under the impression that vigorous boiling removes O2 from wert, I can't imagine how boiling would introduce HSA.

http://www.elmhurst.edu/~chm/vchembook/images2/174solublegas.gif

- M

That it may, but a big splashy rolling boil will aerate. So goes the legends anyway.

 

[iamatuna]

Has anyone ever tried what was talked about here?

I am thinking of making a helles and want it to have a SOLID head on it

So far I am thinking that i will
-use distilled water to remove the reducng potential and to make it softer to bring out the malt and reduce hop
-use a 90 minute VIGEROUS boil to increase the degredation of LTP1 and other proteins and polymers
-make sure the boil is acidic

think it will work?