HOMEBREW Digest #5198 Wed 20 June 2007


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Contents:
  Re: Olive oil (Fred L Johnson)
  Sweeteners ("A. J. deLange")
  Re: Olive oil (**major error rectified**) (stevea)
  Re: Olive oil (Fred L Johnson)
  Pump Cleaning (Dana Edgell)
  Re Darrell's experiment ("Pat Casey")
  Re: Corn Mash ("Paul Erbe")

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---------------------------------------------------------------------- Date: Tue, 19 Jun 2007 23:13:16 -0400 From: Fred L Johnson <FLJohnson52 at nc.rr.com> Subject: Re: Olive oil Steve pointed out that the yeast supplemented with oil grew to a greater extent than did the yeast supplemented with free fatty acids. The methods weren't described in post, but I must assume that the authors provided the yeast approximately the same masses of free fatty acids as they supplied oil, otherwise I don't know how one should interpret the results. I don't believe it has been stated how much of each lipid class (triglycerides, phospholipids, sterol esters, and free fatty acids) was present in the yeast after the fermentations. I would guess that triglycerides accounted for the bulk of the difference between the control fermentation (i.e., the fermentation with no additions) and the fermentations in which free fatty acids, oil, or lecithin were added. Regarding the methods used, it is likely that the lipids were extracted first (Folch-Lees method, chlorofom:methanol, 2:1) and that the lipids were either fractionated into classes and then each class was saponified to determine the fatty acid content of each class or the total the Folch-Lees extraction was saponified. I'm not surprised that the yeast accumulated significant amounts of PUFAs when supplied with a source rich in these, especially if the bulk of the accumulation is as triglyceride. Cells are often more picky with the type of fatty acid used to esterify to phospholipids, especially esterification at the 2 position, because the phospholipids serve more of a structural role and membrane fluidity must be regulated by the fatty acid composition of the phospholipids and by the amount of sterols in the membranes, but when it comes to storage triglycerides, I suspect they esterify whatever happens to be most abundant. That the yeast utilized the triglycerides (olive oil) still surprises me. Perhaps they have a triglyceride lipase on the external side of their cell membrane that can somehow act on an emulsion droplet that the cell encounters. I'd like to hear more about what is known about yeast ability to utilize triglycerides from the outside. They are well known to store triglycerides internally and to be able to use these stored triglycerides when energy is needed, but I am ignorant of their ability to utilize external triglycerides. Perhaps there is a yeast microbiologist among us that can enlighten me. I know we must be losing folks by now, so I'll refrain from blathering on. Fred L Johnson Apex, North Carolina, USA Return to table of contents
Date: Wed, 20 Jun 2007 04:00:45 +0000 From: "A. J. deLange" <ajdel at cox.net> Subject: Sweeteners RE: Anybody know of sweeteners that are definitely not fermentable by Brett, lactobacillus, and the other creatures in a Flanders Red? Yes. I'm writing from Victoria where I am at the ASBC Annual Conference. A paper was given this morning on Palatinose(TM) which is isomerized sucrose. According to the presenter (Roland Paul of VLB) nothing will eat this stuff except Schizosaccharomyces Pombe. A.J. Return to table of contents
Date: Wed, 20 Jun 2007 02:13:06 -0400 From: stevea <steve-alexander at adelphia.net> Subject: Re: Olive oil (**major error rectified**) Fred L Johnson wrote: > Steve pointed out that the yeast supplemented with oil grew to a > greater extent than did the yeast supplemented with free fatty acids. > The methods weren't described in post, but I must assume that the > authors provided the yeast approximately the same masses of free fatty > acids as they supplied oil, otherwise I don't know how one should > interpret the results. I apologize, but of course I can't post the full paper here. They created a lipid extract from malt and then performed a fairly detailed analysis of the components. The highlight are that the wort addition consisted of 5.9mg/l of free sterols and 9.5mg/l of total sterols (~20% campesterol, 5 =% stigmasterol and 75% beta-sitosterol). Also the addition included 86ppm of free FA and 314 of total FA ( roughly 30% C16, 14% C18:1 and 55% C18:2, 5% C18:3) . The association of the FAs was also analysed in some detail. Briefly 3% mono-glyceride ,7% diglycerie, 18% phospholipid, 28% freeFA, 41% triglyc... and 2% associates with sterols. Having analysed the fermentation with this lipid mix addition, they then performed ferments adding commercial "pure lipids " to similar ferments. (using beta-sitosterol 10mg/l, lecethin 40mg/l, linoleic 30mg/l, linolenic 3mg/l, oleic 8mg/l, trilinolenin 7mg/l, trilinolein 80mg/l and triolein 20mg/l). These were tested as a totoal mix, and as the mix minus one component at a time. Note that the total-mix has about the same total sterol but only ~190ppm of FA (vs 314 for the malt extract). The total mix has very smililar results on fermentation and the (undetailed report) is that the yeast lipids were affected in a similar way with the plant sterols addint to the yeast sterols and modestly shifting the yeast sterol mix, and the FA levels being similar to the control aside from a big boost in PUFAs. **** Now here is something I serious mis-reported previously (sincere apologies). Fred was right. When reading the charts I did not see that the rows were the total-mix minus one component. So the total mix provided the best performance (greatest attenuation and highest yeast mass), and the mix minus the triglycerides was almost as good [bad mistake here earlier], The mix minus the free FAs was only marginally better than the control. **** So Fred was right and I misinterpreted the chart. The freeFAs are the biggest growth improvement factor and the triglycerides almost ignorable. [Having said that, note that the amount of PUFAs in the yeast exceeded the free FA PUFAs added.] The lecethin seems to be a significant factor, but it is expected that this is because of it's role as a surfactant. > I don't believe it has been stated how much of each lipid class > (triglycerides, phospholipids, sterol esters, and free fatty acids) > was present in the yeast after the fermentations. Because of the yeast lipid saponification method no such analysis was possible. Instead they give breakdowns of the sterol components and FA components but not the original configuration. > That the yeast utilized the triglycerides (olive oil) still surprises me. No surprise - the nearsighted guy misread the crummy xerox copy. > I know we must be losing folks by now, so I'll refrain from blathering > on. Well if they sorted out the imperial vs US measures and metric teaspoons thread then we have the place to ourselves, so let's continue. So let's say we have some veggie oil with a desirable FA assay. How would we go about converting the tri- & di- glycerides to free fatty acids in a fermentation friendly way ? Conventionally you add a strong base to the oil (sodium or potassium hydroxide), to create FA salts and free glycerol. We have no need to remove the glyceol (yeast produce plenty). Is the amount of sodium or potassium an issue ? It's about 10-16% of the FA salt mass and if we add 1gm of FA salts to 5gallon of beer it's about 5 ppm of sodium or 8ppm of potassium. This assumes we separate any excess x-hydroxide. The low pH of the "soap" shouldn't be a problem. Not a big issue I think. Any thoughts on practical aspects Fred ? -S Return to table of contents
Date: Wed, 20 Jun 2007 06:54:06 -0400 From: Fred L Johnson <FLJohnson52 at nc.rr.com> Subject: Re: Olive oil Thanks, Steve, for looking again at the paper. I was feeling the strong urge (need) to run to the library to bone up on plant lipid biochemistry. Steve wrote: > So let's say we have some veggie oil with a desirable FA assay. How > would we go about converting the tri- & di- glycerides to free fatty > acids > in a fermentation friendly way ? Conventionally you add a strong base > to the oil (sodium or potassium hydroxide), to create FA salts and free > glycerol. We have no need to remove the glyceol (yeast produce > plenty). > > Is the amount of sodium or potassium an issue ? It's about 10-16% of > the FA salt mass and if we add 1gm of FA salts to 5gallon of beer it's > about 5 ppm of sodium or 8ppm of potassium. This assumes we > separate any excess x-hydroxide. The low pH of the "soap" shouldn't be > a problem. Not a big issue I think. > > Any thoughts on practical aspects Fred ? > I think Steve's got it right. I think you can simply do the stoichiometry for the saponification and add an extra 10% base to ensure complete saponification and then just throw the whole mixture into the wort. I'm not a real chemist, but I have access to many, and I'll try to confirm the conditions for the saponification. Fred L Johnson Apex, North Carolina, USA Return to table of contents
Date: Wed, 20 Jun 2007 08:55:28 -0400 From: Dana Edgell <dedg at lle.rochester.edu> Subject: Pump Cleaning HBD, I have a March pump of unknown origin in my possession. There is a dried blue substance in the seals & pump area presumably from what it was used to pump. What would be a sufficient cleaning protocol to ready this for use in brewing? Is there a sufficient cleaning protocol to render it safe or should I not use it? Thanks for your advice. Dana Edgell - -- Dana Edgell Laboratory for Laser Energetics, University of Rochester Rochester, New York Return to table of contents
Date: Wed, 20 Jun 2007 23:55:33 +1000 From: "Pat Casey" <pat at bmbrews.com.au> Subject: Re Darrell's experiment It's not the grain bill that's making the difference, it's the yeast. Yeast adsorp iso-alpha acids, as the yeast floc out they remove the iso-alpha acids with them. This is why the sweet wort is always more bitter than the finished beer. So with the greater amount of yeast in Darrell's second beer it ends up less bitter. A couple of years ago I split a wort. In one half I just sprinkled the dry yeast, for the other half I rehydrated the yeast and aerated the wort with an aquarium pump and stone. A very late write up is at http://www.bmbrews.com.au/?page_id=54 The result was two different beers. The differences were not just due to the greater adsorption of iso-alpha acids, but also to the far better quality of fermentation. Fermentation has a far greater effect than most people realise. With that little experiment I was expecting noticeable differences, but not to that extent. This has all sorts of interesting ramifications, for example with Darrell's beers I think that the differences in fermentation have dwarfed any differences between corn and rice in the grain bill. Makes you wonder about the value of so-called clone recipes. Pat Casey Blue Mtns Brewing Supplies/Absolute Homebrew, NSW www.bmbrews.com.au Return to table of contents
Date: Wed, 20 Jun 2007 09:59:05 -0500 From: "Paul Erbe" <paul at theerbes.com> Subject: Re: Corn Mash John asks about doing a Corn Mash and letting it sit for up to 8 hours. I have done long mashes and some overnight mashes. My concern with this style is that it is normally light and bittered at a lower level. This all means there is very little to cover any flaws. Letting a mash sit has the potential for souring. Might be great in a Dry Stout but not so pleasing in a clean American Lager Paul Erbe NW suburbs of Chicago. Return to table of contents
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