HOMEBREW Digest #5192 Thu 07 June 2007

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  Olive Oil (Jeremy Bergsman)
  Re: Olive Oil (Fred L Johnson)
  re: Olive Oil ("-s@adelphia.net")
  Malt Madness Homebrew Competition ("Al Hazan")

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---------------------------------------------------------------------- Date: Thu, 07 Jun 2007 00:35:00 -0400 From: Jeremy Bergsman <jeremy.bergsman at gmail.com> Subject: Olive Oil Well, I'm sure -S will chime in on the biochemistry, but if their biochemistry is as good as their math, I wouldn't take New Belgium's advice here (unless they are brewing 18 million gallon batches). Maybe they mean 300 microliters.... - -- Jeremy Bergsman jeremy at bergsman.org http://bergsman.org Return to table of contents
Date: Thu, 7 Jun 2007 07:11:15 -0400 From: Fred L Johnson <FLJohnson52 at nc.rr.com> Subject: Re: Olive Oil I would expect that making soap from the olive oil would be a much better way of providing fatty acids to the yeast (if that is what you want to do). I doubt yeast have very much if any capacity for transporting triglycerides into their cells. Perhaps they secrete triglyceride lipase (or spill their guts at their death), but hydrolyzing the fatty acids away from the glycerol backbone would still likely work much better than adding oil. Fred L Johnson Apex, North Carolina, USA Return to table of contents
Date: Thu, 07 Jun 2007 14:27:50 -0400 From: "-s at adelphia.net" <-s@adelphia.net> Subject: re: Olive Oil I'm in the middle of some urgent work so I'll have to make a brief reply to Matt Baum's belated discovery that need unsaturated fats made with oxygen. > "The basic concept is that since yeast uses an oxygen atom to pull a > hydrogen away from an 18 carbon chain unsaturated fatty acid to make a > monounsaturated fatty acid chain to help it grow, you could simply > provide an 18 carbon monounsaturated fatty acid and it would be able to > use that. This works well in practice, we made a little over 1 million > bottles with beer where the yeast had had olive oil added. > I microbiologist who used to post here long ago [wasn't Liddel - can't remember the name] was (as far as I know) the first to cite a report on this to the HB community. His reference paper demonstrated that yeast can live anaerobically (forever, not just 4 generations) so long as they are supplied with UFA(unsaturated FAs) and sterol. I believe that was reposter on HBD circa 1995. Not news. Charlie Scandrett (who hasn't posted here in ~7 years) reported on a paper that described the FA uptake method of yeast. Not news. ... > the > amount you actually need is pretty small. Additionally, you want to use > a very small amount to avoid any detrimental effects that the oil would > have on the beer's head retention. > 1/ UFAs are the demons when it comes to head retention. saturated FA are less damaging. 2/ The amount is NOT small. Healthy yeast are abt 10% fat by dry mass and something like 10-20% of this is UFAs (from memory, I'll check later). > "For the volume of wort we normally ferment, we would pitch about 4500L > of yeast, and to that we would add around 300mL of olive oil. To > translate that into a 5 gallon size, you would need to measure about > 0.0000833mL of olive oil. For any practical purpose, that is much too > small an amount to accurately measure out. You could fudge and just add > the tiniest imaginable drop to the yeast you have, but you'd be > over-dosing the oil by thousands of times the required amount, and run > the risk of having zero foam retention. Not a good compromise in my > opinion. > That number is way- wrong ! The amount of FA specified here (0.0000833ml) is low by at least 2 orders of magnitude and I'd wager it's more like 4 ! If you want to supply all the yeast FAs by oil addition then you 'd be measuring with teaspoons, not micropipettes. > Some thoughts: > > First, it's just kind of stunning to hear that this has been done on > such a large scale. > I agree. I've done this on a test scale years ago (1L size) and the impact is pretty clear. > Second "pull a hydrogen away from an 18 carbon chain unsaturated fatty > acid to make a monounsaturated fatty acid chain" doesn't quite make > sense to me and is maybe a typo? > This is a stupid, tho' accurate statement which emphasizes the wrong issue. The guy who wrote it was trying to relay a point he didn't really understand. All they are saying is that yeast convert oleic(saturated c18) to some unsaturated form like linoleic, linolenic ... and use oxygen to do it. C18 FAs are the most common in yeast and most plants, but both yeast and olives also contain and desaturate C16 and C20 and others - just a dumb*ss way of saying yeast need oxygen to make the UFAs they need. > Third, this is not entirely new. Olive oil is mostly unsaturated C18 > fatty acids, and it has been known for quite a while that yeast can > reproduce without oxygen if they are provided linoleic acid (one of the > olive oil components) and ergosterol. > Right - but where are these guys adding the ergosterol (or other sterols) ? That's why it's a lousy method. FWIW yeast make and use a set of sterols - not just ergosterol. Several isomers of zymosterol are significant in yeast for example. I seem to recall sitosterol as well. The cell wall properties vary as you change the sterol mix too ! So that save part of the oxygen by adding UFAs but then they still need it for sterols. > Question 1: Okay so what about that ergosterol? Does the linoleic, > oleic, or anything else in olive oil allow yeast to produce sterols? No ! There are plant sterols that can be substituted (perhaps at a performance cost), but the concentration in plant lipids is too low for yeast unless you separate & concentrate these. The other problem is that UFAs & sterols make for better more efficient yeast membrane - good thing. But normally *sterol* is the growth limiting factor in brewery fermentation. In most cases yeast will stall for lack of sterol, not UFAs. > Aside from the obvious worry about head retention, one might worry > about oxidation products of leftover oil. (As with trub.) On the > other hand, New Belgium is something like the 11th largest US brewery > and has trained tasters and all that kind of thing. > > Anyway this is kind of interesting. > Yeast are voracious fat eaters. They will consume more than they need. Unless you add truly radical amounts of olive oil - no worries. The qty cited is way too small to have any impact. Yeast need O2 for UFAs and sterols. You need both but the sterols are more critical as growth liming factors. You'll need to add the lipids in an emulsified form. The yeast need to wallow in the grease - they can't use the oil in a droplet floating on the surface. *Maybe adding these at the boil would work. -S Return to table of contents
Date: Thu, 7 Jun 2007 19:46:33 -0400 From: "Al Hazan" <hazan at ptd.net> Subject: Malt Madness Homebrew Competition The Lehigh Valley Homebrewers (LVHB) proudly announces their homebrew competition, Malt Madness will be held on Saturday, September 8th at the Allentown Brew Works in Allentown, Pa. All BJCP recognized styles (2004 guidelines) including meads and ciders are eligible for entry. For complete details and forms, please visit the LVHB web site at http://www.lehighvalleyhomebrewers.org. Entries will be accepted from August 15th through August 30th. For drop off and mail in locations please refer to the LVHB web site. Please, do not mail entries to the Allentown Brew Works. BJCP Judges and stewards will be needed. If you are interested please contact me at the below address. All judges must be BJCP certified (any ranking) or have relevant experience. Good luck. Al Hazan Competition Organizer hazan at ptd.net Return to table of contents
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