HOMEBREW Digest #4965 Thu 02 March 2006

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  A2, MI  local suppliers ("Michael M. McClatchey")
  More well water analysis (Calvin Perilloux)
  Re: Brewing Coppers (Glyn)
  RE: Brew Shops in MI (Mike LaCour)
  yeast starter step sizes and gravity (ALAN K MEEKER)
  re: Yeast starters (RI_homebrewer)

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---------------------------------------------------------------------- Date: Thu, 02 Mar 2006 06:37:17 -0700 From: "Michael M. McClatchey" <mmm at promail.com> Subject: A2, MI local suppliers The Beer Depot on William downtown has almost everything. Home Winery Supply in Dundee is fairly close, and once a month they sell all-grain wort in a distinctive style for $25 for five gallons. There's a shop in Dearborn I've never been to. Return to table of contents
Date: Thu, 2 Mar 2006 07:11:01 -0800 (PST) From: Calvin Perilloux <calvinperilloux at yahoo.com> Subject: More well water analysis David Jones asks for opinions on his well water, which has these significant (brewing-edited) components : Sodium 7 ppm Calcium 77 Magnesium 23 TotHrd CaCO3 288 Sulfate 29 Chloride 22 Bicarbonate 220 Nice midrange water, David. Your chalk content is rather high for some styles (especially the notorious soft-water Bohemian Pilsner), but it's not too bad for many styles. For some pale brews (e.g. BohPils) requiring low- mineral-content water, consider removing some of the carbonate via the "boil+aerate chill and decant" method. Or use distilled water dilutions. Note that if you do this, you are also removing calcium, so you might be interested in an acid rest during mash or perhaps a (small) shot of "5.2" or other treatment. I've been tending lately toward using more distilled water dilutions rather than the boil+aerate method. Distilled water costs me money, but I've found that my propane bill does as well. With the last batch I used this on, when I included this and the usual propane usage for mash/sparge water and a long boil, I ripped through half a 20-lb tank for one 5-gallon batch of beer. Ouch. As is often the case, you might want to add gypsum for Burtonising your water. In fact, your water is well suited for such treatment, and you can come reasonably close with the addition (per 5 gallons of your water as it is out of the tap) of 15g gypsum and 7.5 grams Epsom salts. That's 1 ounce and half an ounce for unmetrified folk. > Bicarbonate is closest to Dortmund or Edinburgh Note that Dortmund and some other places with carbonate- containing water are pros at pre-treatment of their water. That means that the water they are brewing with might vary from the water that comes out of the ground/tap. In the case of Dortmund especially, I have read that emulating their beers does not mean emulating their water. Calvin Perilloux Middletown, Maryland, USA Return to table of contents
Date: Thu, 2 Mar 2006 08:21:43 -0800 (PST) From: Glyn <graininfuser at yahoo.com> Subject: Re: Brewing Coppers When I was growing up in the hills of East TN, we made our own. Find ya a tree of the right diameter, log it off leaving a semi-high stump. Round off the top of the stump, should be easier now with them there new-fangled saws. Take your sheet of copper and form it around the stump. Care should be taken to do this out site as you don't want any revenuers poking around. Glyn Born and raised back in an East TN holler Return to table of contents
Date: Thu, 2 Mar 2006 09:15:46 -0800 (PST) From: Mike LaCour <mblacour at yahoo.com> Subject: RE: Brew Shops in MI Brian, I'm right down the road from you in Brighton. I've found the best brew shop in the area is Things Beer in Webberville, MI. After getting your homebrew supplies stop by Michigan Brewing Co. for a pint. Mike mblacour at yahoo.com Return to table of contents
Date: Thu, 02 Mar 2006 13:00:46 -0500 From: ALAN K MEEKER <ameeker at mail.jhmi.edu> Subject: yeast starter step sizes and gravity Fred asked about yeast starters - why the recommendations for modest gravity starter wort and incremental step sizes not exceeding 10-fold steps? Fred, I don't believe these limitations are driven by concern over adequate oxygen supply. The advice to use moderate gravities makes sense in that high gravity (which mostly means high sugar concentration) represents a stressful situation for the yeast which could compromise the vitality and viability of the resulting starter - you don't want to be pitching highly stressed-out yeast into your wort as this can obviously lead to all kinds of problems including poor or inconsistent performance and stuck ferments. HIgh gravity is osmoticaly stressful from the high sugar content, may be relatively low in non-sugar nutrients, particularly nitrogen- based (also stressful), and can lead to higher final levels of toxic yeast metabolites (e.g. ethanol). To make a perhaps not so great analogy, think of the starter as an entry-level work force that you are training to conduct a very large job. If you push them too hard during training then when it comes time to tackle the big job they will be going into it exhausted, burnt-out, sleep-deprived wrecks. This won't give you optimal performance. The common advice to expand starter volume in stages, with each step being no more than about a 10-fold dilution stems more from worries about allowing bacterial contamination to multiply to levels that will have detrimental effects in the final fermentation. The idea here is that bacteria can multiply much faster than yeast (bacterial generation times can be as fast as 15-20 minutes, while yeast take a couple of hours to multiply), Thus, if allowed to grow unchecked, a bacterial contamination could grow to high enough density in the starter to produce negative flavor effects in the finished beer. The key here is the bit about bacteria growing /unchecked/. What hapens is that if you have significant yeast growth they will quickly make the environment inhospitable for the growth of most bacteria. They accomplish this in a number of ways including acidification, nutrient/oxygen depletion, and ethanol production. Thus, if you innoculate each step of the starter with sufficient yeast they will quickly squelch the growth of any competing bacteria that are also present (and in the homebrew setting there will almost always be some bacteria around). This is why folks recommend stepping up in dilutions of 10-fold or even less. If you dilute a saturated yeast culture 10-fold it only takes a little more than 3 divisions to get back to saturation. If the yeast are growing as fast as they can this will only take about an hour or two. However, even more quickly they will make conditions bad for any bacteria present, so you will rapidly get suppression of bacterial growth. Now take an extreme example where you do the maximum dilution step possible, that is, start with only a single yeast cell, it will take this single cell many many divisions to create a yeast population of sufficiently high density to start conditioning the wort against bacteria, something on the order of 20+ divisions for a volume of about 1 liter. That's 20 divisions at 2 hours per division, or about 40 hours. Now, let's say there was also a single bacterium present at the beginning. This bacteria can divide every 20 minutes, thus over the same 40 hours can divide a whopping 120 times. This would produce something like a million kilograms of bacteria if growth was unrestricted. Obviously the 1 liter culture would run out of nutrients LONG before that could ever happen, but the point is clear - without the yeast's attenuating influence, even a small bacterial presence could easily gain a foothold leading to problems later on down the line. Alan Meeker Baltimore, MD Return to table of contents
Date: Thu, 2 Mar 2006 16:34:59 -0800 (PST) From: RI_homebrewer <ri_homebrewer at yahoo.com> Subject: re: Yeast starters Hi All, In HBD #4964 Fred Johnson from Apex, NC asked about the 10 fold step up rule-of-thumb for yeast starters. My understanding is that this rule-of-thumb is used to prevent the yeast cells from being too dilute when pitching into the starter. Supposedly, this increase step size keeps the cell count near the suggested level (1E6 cells per ml per degree plato?). If it's more dilute, then it's less likely the yeast will out compete the other organisms that are inevitably in the starter wort. I would also imagine that if the yeast were more concentrated, they may run out of sugars or nutrients before dividing the desired number of times. Jeff McNally Tiverton, RI (652.2 miles, 90.0 deg) A.R. South Shore Brew Club Return to table of contents
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