HOMEBREW Digest #5476 Wed 24 December 2008

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  Re: Oxygenation ... ("steve.alexander")
  Re: Water (Jeff Renner)
  Merry Christmas! ("Pat Babcock")

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---------------------------------------------------------------------- Date: Wed, 24 Dec 2008 04:26:02 -0500 From: "steve.alexander" <-s at roadrunner.com> Subject: Re: Oxygenation ... David Kudrav asks > Recent discussions have raised the following questions in my mind: > > 1. I've never gone out of my way to oxygenate, other than using a funnel > with a filter after cooling the wort to transfer from my boil pot to my > fermenter (filter and funnel to remove hops and debris from bottom of boil > pot). But I've never noticed any type of problem with my beer without > forced oxygenation. Should I force oxygenate, with a stone & gas > tank?--what difference would I notice in my beer? Other people have had > my beers and like them (ie, no obvious problems with most batches). > First I'll suggest you oxygenate with air as a starting point. Many methods have been suggested. pouring wort between buckets, pumping filtered air with an aquarium pump, beating with a whisk, shaking carboys vigorously. Yeast require oxygen to make unsaturated fatty acids and sterols for their cell membranes. When it is lacking you'll have more migration of "things" across the cell membranes interior and exterior to the cell. The cells will operate far less efficiently and ultimately the lack of air (or UFAs and sterol) can be the reason yeast growth stops and greatly reduces the rate of fermentation (stuck fermentation). If you add some oxygen you'll generally end up with less fusels and esters, a faster fermentation and less yeast flavor in the beer. You may possibly get a little better attenuation, particularly in hi-grav beers. The final cells in the bottom will be in much better health if you repitch. > 2. What of olive oil as substitute for oxygenation? I've read an article > or two about this, but am not sure I'm convinced of it. Is the chemistry > sound, or is it bunk? Does anyone use this method? What are the results > The biochemistry is not nonsense but the common practice is bunk. Veggie oil is a combination of glycerices with various levels of desaturation. Yeast can uptake the olive oil, and this may reduce the oxygen required. The amount suggested in brewing forums is ridiculously low; by a factor of 100 or more. If you look through this forum's archives you'll see I once did a calculation and the amount of OO needed is on the order of an ounce per 5 gallons of wort (well 20ml). The problems are considerable. Yeast should be able to consume large quantities of such oil, but if the yeast fail to clear all the olive oil then it will kill head terribly. Phospholipids in wort *may* help disperse the oils, but most likely you'll end up with an oil-slick on top. Perhaps lecithin would help emulsify the oil. Fred Johnson suggested salts of fatty acids (soap); but in either case care must be taken to not disrupt the yeast cell membranes. In the lab they use Tween80 - an oleic acid compound which is very soluble in water. Oil additions will greatly reduce the ester level in beer and may not be appropriate for estery ales. The other problem not addressed is that yeast require oxygen to make sterol from squalene. Olive Oil can't supply enough sterol to help so you still could use some oxygen. If you want to experiment I'll suggest you try an olive oil addition to a starter. Actually other oils (perhaps flax) would have less negative flavor impact and higher desaturation levels. -S Return to table of contents
Date: Wed, 24 Dec 2008 08:45:32 -0500 From: Jeff Renner <jsrenner at umich.edu> Subject: Re: Water "Keith Christian" <keithchristian at roadrunner.com> wrote: > My Anaheim CA water is unbelievably hard. When sanitizing, I have > been > using RO water with StarSan. I want to use my tap water that has gone > through the water softener instead. Will that work alright? I want to > stop using the RO water for sanitizing. If your water has temporary hardness, i.e., it contains bicarbonate ions rather than sulfate ions, then your softened water will still have a high level of alkalinity. This means that StarSan made up with softened water will still sanitize, but it won't keep long. StarSan is effective as long as it is clear (and of proper concentration, of course). It will go cloudy if the pH rises too high. It's not hardness (calcium and magnesium ions) per se that causes StarSan to go cloudy and ineffective, but the alkalinity from the bicarbonate ions typically associated with the calcium and magnesium. A water softener does not affect the alkalinity of water. It substitutes sodium ions for calcium and magnesium ions. It doe not change the anions associated with the sodium and magnesium. RO water is cheap enough that I use it to make up StarSan and it keeps for weeks. Jeff - --- Jeff Renner in Ann Arbor, Michigan USA, jsrenner at umich.edu "One never knows, do one?" Fats Waller, American Musician, 1904-1943 Return to table of contents
Date: Wed, 24 Dec 2008 10:44:47 -0500 (EST) From: "Pat Babcock" <pbabcock at hbd.org> Subject: Merry Christmas! Greetings, Beerlings! Take me to your Rennerian Eggnog... Wishing all a safe and merry Christmas. Please be careful out there and savor the flavor responsibly. Hope all your Christmas wishes come true! - -- See ya! Pat Babcock in SE Michigan Chief of HBD Janitorial Services http://hbd.org pbabcock at hbd.org Return to table of contents
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