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Post by brewbama on Mar 30, 2022 20:21:37 GMT -6
I see many brewers here harvest and repitch yeast. I brew about every 3-4 weeks. I use one trip dry yeast. I always felt like I don’t brew often enough to concern myself with harvesting and repitching. A few questions:
1) how long do you store yeast before repitching?
2) when repitching what was originally dry yeast, do you oxygenate?
3) do you top crop during active fermentation or wait until ferment is complete to harvest from a fermenter?
4) if you spund, do you harvest from the keg?
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Post by Ken on Mar 30, 2022 21:03:43 GMT -6
1) It depends but it's usually close... like within a few days. Here's something: What if I brew on a Saturday and then transfer the beer to the keg on the following Friday and then use it Saturday? That's one day. What if I brew on a Saturday and don't do the transfer until the next Friday (13 days total) and then brew the next Saturday? The time from harvest to brewing is still one day. But obviously the yeast has been sitting somewhat (or totally) dormant for longer. On four of these batches I made with S-04, I used the yeast 4 times in 4 weeks but on the 5th one the yeast sat in the fermenter for about 13 days instead of 6-7.
2) I always oxygenate. First use of a dry or liquid yeast and all repitches.
3) I wait until fermentation is complete and harvest after the beer has been sent to the keg.
4) No spunding here. I tried it but couldn't get consistent carb.
Good conversation, BB.
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Post by tommymorris on Mar 31, 2022 7:28:57 GMT -6
1) how long do you store yeast before repitching?
I usually collect the yeast and reuse within 2-3 weeks.
2) when repitching what was originally dry yeast, do you oxygenate?
I don't oxygenate. I never have. I try to remember to use yeast nutrient. I usually over pitch slurry by a factor of 2 according to Mr. Malty. Not sure if that matters.
3) do you top crop during active fermentation or wait until ferment is complete to harvest from a fermenter?
I wait. I drain the fermenter in to the keg and then swirl the remaining beer and yeast. I wait 5 minutes and then pour off into a mason jar.
4) if you spund, do you harvest from the keg?
I don't spund. I want to try that soon.
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Post by Ken on Mar 31, 2022 7:41:50 GMT -6
Also, I seem to remember that the guys on the LO forum were saying that harvested yeast that is sitting in a container and in the fridge can be used as "fresh yeast" for up to about three weeks. That number was bounced around but I seem to remember it settling around three weeks. Anything after that and you might consider some steps to freshen it up. Someone mentioned a "vitality starter" and I might have this confused with something else and if so, please advise. On brewday when you're collecting wort, set some aside and boil it and let it cool. Then add it to the container that the yeast is stored in and leave it at room temp. It's a snack for the yeast and it's assumed that there will be an hour or two from that point where the yeast can wake up and get moving while you run off, boil, chill, transfer, etc. I've done it a few times.
On the topic of O2... I hear A LOT of people who say they do not use it including Denny. I thought it was clear that yeast need O2 all throughout the process. I might start a thread over on AHA to get some feedback. I use O2 in starters and every single time I pitch yeast whether it's dry, liquid, a first run, harvested, etc. I get very quick starts but that doesn't necessarily mean it's the O2 doing that.
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Post by denny on Mar 31, 2022 13:04:05 GMT -6
I see many brewers here harvest and repitch yeast. I brew about every 3-4 weeks. I use one trip dry yeast. I always felt like I don’t brew often enough to concern myself with harvesting and repitching. A few questions: 1) how long do you store yeast before repitching? 2) when repitching what was originally dry yeast, do you oxygenate? 3) do you top crop during active fermentation or wait until ferment is complete to harvest from a fermenter? 4) if you spund, do you harvest from the keg? 1) usually 3-4ish weeks. Sometimes longer, but then I make a starter before repitching 2) no more than usual, which is little to none 3) post fermentation 4) N/A
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Post by brewbama on Mar 31, 2022 15:48:03 GMT -6
1) I usually collect the yeast and reuse within 2-3 weeks. 1) usually 3-4ish weeks. Sometimes longer, but then I make a starter before repitching 2-4 weeks would fit my schedule. Good to hear. Thx folks! |
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Post by tommymorris on Mar 31, 2022 18:31:20 GMT -6
One thing I haven’t done but have considered is keeping the yeast longer and then making a SNS start with 2 TBS of slurry. That would freshen the yeast and clean it up (get rid of a lot of true and hops that might be in the slurry).
My habit is to use a yeast 2-3 times and then toss it. I get bored and want to move on. Because of that I have never done the above.
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Post by Ken on Mar 31, 2022 18:36:50 GMT -6
One thing I haven’t done but have considered is keeping the yeast longer and then making a SNS start with 2 TBS of slurry. That would freshen the yeast and clean it up (get rid of a lot of true and hops that might be in the slurry). My habit is to use a yeast 2-3 times and then toss it. I get bored and want to move on. Because of that I have never done the above. I got into some trouble "saving" yeast. I don't "save" it as much as I "reuse" it. For awhile I had bottles of yeast in the fridge and I figured I would create a "yeast library" and use whichever strain I wanted whenever I wanted. HA! How little I understood. When I reused many of them the beers came out poorly because that yeast was stuck in those bottles for a long time. This was a long time ago. So I reuse it now and I'll go 6, 7, 8 times. I think I used 940 or 2124 eleven times one year. I can make so many different styles with them that I don't get bored. One lager strain can create a bunch of styles so you just have to keep brewing different things. |
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Post by tommymorris on Apr 1, 2022 12:52:17 GMT -6
I’ll be honest the need for low oxygen in the mash followed by the need for super saturated oxygen for fermentation confuses me. How is it that staling happens so fast in the mash but we can super saturate with oxygen before adding yeast with no staling. I know the yeast absorbs oxygen but that can’t be instantaneous and must have a limit. Can’t we add too much oxygen?
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Post by Megary on Apr 1, 2022 14:24:59 GMT -6
I’ll be honest the need for low oxygen in the mash followed by the need for super saturated oxygen for fermentation confuses me. How is it that staling happens so fast in the mash but we can super saturate with oxygen before adding yeast with no staling. I know the yeast absorbs oxygen but that can’t be instantaneous and must have a limit. Can’t we add too much oxygen? Not sure if this helps, but I stole this from Wyeast, thanks to HighVoltageMan!: wyeastlab.com/resource/home-enthusiast-oxygenation-aeration/Some yeast strains have higher oxygen requirements than others. However, it is generally safe to assume that you need at least 10ppm of oxygen. 10ppm will supply adequate oxygen in most situations. Over-oxygenation is generally not a concern as the yeast will use all available oxygen within 3 to 9 hours of pitching and oxygen will come out of solution during that time as well. Under-oxygenation is a much bigger concern. |
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Post by brewbama on Apr 1, 2022 16:04:04 GMT -6
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Post by Megary on Apr 1, 2022 16:32:24 GMT -6
That’s 20 minutes in sugared RO water with Red Star Dry (Bread) Yeast. In the “wort study”, it’s more like an hour. But, that’s splitting hairs I guess. Do those studies apply across the board, or just in their brew house? I haven’t seen Wyeast’s study as to where they came up with 3-9 hours. |
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Post by Ken on Apr 4, 2022 10:39:25 GMT -6
I typically add the sugar + yeast 1-2 hours prior to heating the strike water. I know I heard the 20-minutes number and I believe I also heard that dosing the water with yeast + sugar can keep that water at zero DO (or close) for up to 2 days! That surprised me.
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