Comments on: Aeration and Yeast Starters http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/ If accidentally read, induce vomiting. Thu, 10 May 2012 18:07:38 -0600 hourly 1 http://wordpress.org/?v=3.3.1 By: webmaster http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-568 webmaster Tue, 01 Nov 2011 17:32:22 +0000 http://seanterrill.com/?p=1399#comment-568 Jerry, I did write up a separate post on yeast propagation: <a href="http://seanterrill.com/2010/03/23/yeast-ranching-and-you/" rel="nofollow">Yeast Ranching and You</a>. Let me know if there's anything that isn't covered there. All I do to sanitize the plastic aerators is soak them in iodophor for an hour or so. Although to be completely honest, when it's a new one straight from the package I don't generally bother. I do make sure that the air pump is running the entire time the stone is in contact with the wort. Hopefully that means that little to no wort will end up inside anyway. And after using a stone two or three times I just throw it away. Sean Jerry,

I did write up a separate post on yeast propagation: Yeast Ranching and You. Let me know if there’s anything that isn’t covered there.

All I do to sanitize the plastic aerators is soak them in iodophor for an hour or so. Although to be completely honest, when it’s a new one straight from the package I don’t generally bother. I do make sure that the air pump is running the entire time the stone is in contact with the wort. Hopefully that means that little to no wort will end up inside anyway. And after using a stone two or three times I just throw it away.

Sean

]]> By: Jerry http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-567 Jerry Tue, 01 Nov 2011 04:48:17 +0000 http://seanterrill.com/?p=1399#comment-567 Thanks Sean, for the information you provide here and on basic brewing radio. The idea of propagating yeast from a starter instead of harvesting from the fermenter seems to me an excellent one. Care to share your methods for doing this? Another question: Those plastic aeration stones - do you sanitize them before using, if so, how? Thanks Sean, for the information you provide here and on basic brewing radio. The idea of propagating yeast from a starter instead of harvesting from the fermenter seems to me an excellent one. Care to share your methods for doing this?

Another question: Those plastic aeration stones – do you sanitize them before using, if so, how?

]]> By: Increasing Cell Counts in Starters - Page 2 - Home Brew Forums http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-196 Increasing Cell Counts in Starters - Page 2 - Home Brew Forums Fri, 18 Jun 2010 15:39:01 +0000 http://seanterrill.com/?p=1399#comment-196 [...] I don't know if you've seen this; it's come up in a few other threads. Aeration and Yeast Starters Nowhere near a 4x increase, but clearly agitation/aeration works. __________________ Beer is [...] [...] I don't know if you've seen this; it's come up in a few other threads. Aeration and Yeast Starters Nowhere near a 4x increase, but clearly agitation/aeration works. __________________ Beer is [...]

]]> By: To Stir Plate or Not To Stir Plate? - Home Brew Forums http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-184 To Stir Plate or Not To Stir Plate? - Home Brew Forums Wed, 09 Jun 2010 16:22:48 +0000 http://seanterrill.com/?p=1399#comment-184 [...] shaking is almost as good as a stirplate, and that direct aeration is the best technique of all: Aeration and Yeast Starters Overall it seems that agitation doesn't do much in and of itself (for a low-gravity wort, anyway). [...] [...] shaking is almost as good as a stirplate, and that direct aeration is the best technique of all: Aeration and Yeast Starters Overall it seems that agitation doesn't do much in and of itself (for a low-gravity wort, anyway). [...]

]]> By: Stir Plates and Pitch Rates - Home Brew Forums http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-177 Stir Plates and Pitch Rates - Home Brew Forums Mon, 24 May 2010 16:52:27 +0000 http://seanterrill.com/?p=1399#comment-177 [...] http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/ I have some problems with the methodology, but more importantly according to the write up the stir plate version (see updates, the original experiment lacked a stir plate) resulted in substatially more yeast than the aerated version. The opposite of the claim in the OP. Does Sean Terril say different things in the podcast than he does on his blog? __________________ http://remilard.mybrute.com [...] [...] http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/ I have some problems with the methodology, but more importantly according to the write up the stir plate version (see updates, the original experiment lacked a stir plate) resulted in substatially more yeast than the aerated version. The opposite of the claim in the OP. Does Sean Terril say different things in the podcast than he does on his blog? __________________ http://remilard.mybrute.com [...]

]]> By: Build a Better Stirplate « SeanTerrill.com http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-153 Build a Better Stirplate « SeanTerrill.com Mon, 26 Apr 2010 05:35:48 +0000 http://seanterrill.com/?p=1399#comment-153 [...] (39) Popular PostsAeration and Yeast StartersYeast Ranching and YouWater, Water EverywhereGood Beer, Easy BeerYeast Pitching Rate ExperimentBM2K9 [...] [...] (39) Popular PostsAeration and Yeast StartersYeast Ranching and YouWater, Water EverywhereGood Beer, Easy BeerYeast Pitching Rate ExperimentBM2K9 [...]

]]> By: Tweets that mention Aeration and Yeast Starters « SeanTerrill.com -- Topsy.com http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-150 Tweets that mention Aeration and Yeast Starters « SeanTerrill.com -- Topsy.com Fri, 16 Apr 2010 02:22:00 +0000 http://seanterrill.com/?p=1399#comment-150 [...] This post was mentioned on Twitter by Andy Murphy. Andy Murphy said: Not using an airlock after reading this starter experiment - http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/ [...] [...] This post was mentioned on Twitter by Andy Murphy. Andy Murphy said: Not using an airlock after reading this starter experiment – http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/ [...]

]]> By: webmaster http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-148 webmaster Thu, 18 Mar 2010 21:44:02 +0000 http://seanterrill.com/?p=1399#comment-148 If you’re compensating for the alcohol, then yes, you’re calculating the real attenuation. 75% would be very high for anything except maybe light lagers – that would correspond to about 93% apparent attenuation, or a 1.050 beer attenuating down to 1.004. 75% apparent attenuation is probably a realistic average for ales (1.050 OG, 1.012 FG), but that’s only 61% real attenuation. If you’re compensating for the alcohol, then yes, you’re calculating the real attenuation. 75% would be very high for anything except maybe light lagers – that would correspond to about 93% apparent attenuation, or a 1.050 beer attenuating down to 1.004.

75% apparent attenuation is probably a realistic average for ales (1.050 OG, 1.012 FG), but that’s only 61% real attenuation.

]]> By: agenthucky http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-146 agenthucky Wed, 17 Mar 2010 17:30:19 +0000 http://seanterrill.com/?p=1399#comment-146 I believe I was referring to absolute attenuation. When I figure my FG, I take into account the error from the alcohol present. This would be actual attenuation, correct? If that is the case, is 55% normal? I stand by my average of 75%. I believe I was referring to absolute attenuation. When I figure my FG, I take into account the error from the alcohol present. This would be actual attenuation, correct? If that is the case, is 55% normal? I stand by my average of 75%.

]]> By: webmaster http://seanterrill.com/2010/01/14/aeration-and-yeast-starters/comment-page-1/#comment-145 webmaster Tue, 16 Mar 2010 15:42:08 +0000 http://seanterrill.com/?p=1399#comment-145 I think the <a href="http://www.byo.com/stories/wizard/article/section/121-mr-wizard/931-is-it-possible-to-aerate-your-yeast-too-much" class="bodylink" rel="nofollow">Mr. Wizard column</a> you're referencing deals primarily with pure oxygen infusion rather than aeration. The saturation point for O2 in water is about 8 ppm at STP, but using oxygen it's possible to super-saturate the wort. At that point you may run the risk of oxidizing the cell walls themselves, but my understanding is that the risk is minimal at normal O2 concentrations. For example, the commercial yeast libraries are grown up by using continuous aeration (<a href="http://www.danstaryeast.com/library/aeration-and-starter-versus-wort" class="bodylink" rel="nofollow">ref. Clayton Cone</a>), although they also propagate below 1.002 SG to avoid the Crabtree Effect. In my own brewery, I have several yeast strains that have been propagated for multiple generations from aerated starters, and still provide excellent (and more to the point, consistent) fermentation performance. I also believe that it's a good idea to minimize stress by propagating yeast from the starter rather than the fermenter, and that's actually my normal practice. I'm going to be posting a full writeup of my yeast handling procedures in the near future, as soon as I have a chance to take some better photographs. I think the Mr. Wizard column you’re referencing deals primarily with pure oxygen infusion rather than aeration. The saturation point for O2 in water is about 8 ppm at STP, but using oxygen it’s possible to super-saturate the wort. At that point you may run the risk of oxidizing the cell walls themselves, but my understanding is that the risk is minimal at normal O2 concentrations. For example, the commercial yeast libraries are grown up by using continuous aeration (ref. Clayton Cone), although they also propagate below 1.002 SG to avoid the Crabtree Effect.

In my own brewery, I have several yeast strains that have been propagated for multiple generations from aerated starters, and still provide excellent (and more to the point, consistent) fermentation performance. I also believe that it’s a good idea to minimize stress by propagating yeast from the starter rather than the fermenter, and that’s actually my normal practice. I’m going to be posting a full writeup of my yeast handling procedures in the near future, as soon as I have a chance to take some better photographs.

]]>