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New research on dry yeast

Discussion in 'Yeast' started by nosco, 13/5/18.

 

  1. nosco

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    Posted 13/5/18
    Basically the new research mentioned in this vid says that putting dry yeast directly in to your wort works just as well as re hydrating it. It also says that aerating your wort (no mention of 02) is bad for the yeast. Its basically says its like giving it a sugar hit. It works well while on the sugar but comes down after the sugar hit affecting its health.

    I like this some of his vids but I am a little skeptical at times. He seems really lax on some points but very over the top on other simple points (like stiring your mash well when doughing in for better efficiency).

    Any way does any one have any info on who or where this research came from?

     
  2. MHB

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    Posted 13/5/18
    I would be a lot more interested if he gave the name of the "Trade Event" and the yeast company, as its a bit like "I heard from a mate at the pub..."
    I's been pretty common practice to pitch dry yeast directly into the fermenter, if you pitch enough the need to aerate is and has been questioned for a long time.
    What it comes down to is if you want the yeast to reproduce (without getting stressed/mutating/sick...) Oxygen is vital, strangely sometimes less so in the present brew but certainly for further generations if you want to reuse the yeast (pretty standard in commercial brewing).
    Will follow with interest - if anyone sees instructions on any of the dry yeast packets changing - please let us know.
    Mark
     
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  3. Yuz

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    Posted 13/5/18
    Interesting and helpful info Mark, as like many others I tend to re-use the yeast... I typically get 2-4 batches from one 15g pack of W-34/70. I do try to look after it - avoiding massive temp and pressure changes and also pitching into the next batch ASAP. I don't actually "wash" it, tending to agree with the theory that its naturally formed environment (current batch produced with some alcohol and CO2 on top) serves as its protective "home".
     
  4. MHB

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    Posted 13/5/18
    Actually storing yeast under beer is about the worst way to store it.
    Good that you are taking care of temp and pressure, good to use it ASAP.
    Much better to wash it with sterile water, if you are going multi generation acid washing is also a good idea otherwise the amount of bacteria will grow and you can be fairly confidant that most home brew has plenty of unplanned bugs onboard.
    Mark
     
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  5. fungrel

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    Posted 13/5/18
    upload_2018-5-14_7-40-14.png
     
  6. theSeekerr

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    Posted 14/5/18
    I heard the same thing from a different source yesterday (attributed as something a brewer friend heard from a Fermentis rep), but it's still all hearsay.
     
  7. hoppy2B

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    Posted 14/5/18
    I believe I have read the exact opposite of what you are suggesting. I think it is actually stated on one of the liquid yeast companies website that the best place to store yeast is in beer.
     
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  8. Uyllii

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    Posted 23/5/18
    Thats from wyeast:

    http://www.wyeastlab.com/yeast-storage (Bold emphasis mine)
    But they also say only to keep 3-4 days (max 10-14).
     
  9. MHB

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    Posted 23/5/18
    Yep, pretty common practice to store under beer for short term storage but not recommended for more than say 1 week and that's pushing it.
    Above I said its not the best way to store yeast (well worst) and it is for anything other than pretty much immediate reuse.
    Converse is that washing yeast ups your risk of contamination (infection) and you want to be using sterile de-aired mineralised water, that still isn't regarded as safe for more than a couple of weeks (max).

    In trade if you aren't going to use yeast PDQ its a case of starting with a slant or other pure culture and breading it up.
    Lots of different things have been tried over the years, commercially scheduling yeast is a dedicated task - left to a professional with good lab support.
    Mark
     
  10. hoppy2B

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    Posted 23/5/18
    I'd rather make a starter with a small amount of dry yeast than wash yeast out of a ferment vessel. It just seems like there is less risk of an infection. I've never had a problem with using a small amount of dry yeast from a packet and then resealing said packet. It depends on the strain as to how long dry yeast will stay alive, but I have had it stay alive for years and that is despite what it says on the packet. I don't purge the packet or vacuum seal it.

    If you are brewing large volumes, then sure, collect yeast from the ferment vessel or ferment on the yeast cake of a previous batch.

    I just do what is easiest. I recently bought a bunch of 100 ml lab bottles so I can divide my next 1318 smack pack.
     
  11. golfandbrew

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    Posted 23/5/18
    Wyeast is simply making recommendations for homebrewers not necessarily the "best" way to store yeast.
     
  12. mashmaniac

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    Posted 23/5/18
    Note the more times you successfully reuse yeast, that's one less pack the yeast company gets to sell. OK on a small scale that ain't much, but there are brewers (with frozen yeast banks) that haven't bought yeast for years. Case in point there's a strain of green belt(not available downunder) in Vic that was imported 4 or 5 years ago -one single package (it has drifted but only slightly). As Mark alluded to the biggest danger to continually re culturing your own isn't drift but other nasties getting in there with it.
     
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  13. Uyllii

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    Posted 23/5/18
    I'm not saying that is my general practice to throw out yeast after a week or two. Just quoting the source I had seen.

    At the risk of going way off topic from the OP:

    Personally I steal yeast from my starters rather than the trub cake after a ferment. I have stored it in 300ml mason jars under the starter liquid and on other occasions I have washed it and stored it under distilled water.
    To be perfectly honest I found both ways left me with yeast that worked just as well (after making a fresh starter) as the original smack-pack starter. I have on a few occasions even used the stored yeast over 6 months after stored either way. I don't know if people are just a little precious about their yeast or if I am using robust strains (I usually store Wyeast 1056, 2206 and 2124).
     
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  14. ///

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    Posted 24/5/18
    I’d hate to see years of research by guys like Bolton on oxygen and yeast health derailed by a presentation somewhere ... I’d take with a grain of salt knowing billion of litres are successfully made with oxygen in mind.

    White Labs did cells counts once on direct add vs hydration in water and I am sure almost 50% of cells died on the direct add. But, for a 12 Plato wort the small packs were almost 50% over on cell numbers required.

    Dried yeast are lumped full of O2 at end of processing, so when the hit wort they can spring into action and get through the lag phase earlier and faster. So kinda kills that argument about importance of O2. The O2 makes the fatty acid walls of the cells softer than without, hence the short lag time.

    As for storage, well I usually had 5000l on top, which was come to come pitched warm to the next for 6-8 gens. Anytime we repitched yeast cold was a probs, for home use this is a bit easier, but my advise is to always use warm yeast not cold
     
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  15. hoppy2B

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    Posted 25/5/18
    While we are on the topic of yeast and methods of pitching...

    Why would pitching a greater amount of yeast give you greater attenuation? I have read enumerable times that if you under pitch, the yeast will fail to eat all of the sugar, thereby leaving your beer under attenuated. To me that just sounds like a load of BS.

    Example: You have gone through a fermentation on 2 identical batches and you pitched 10 times the amount of yeast into one compared to what you did the other. Now, what actually happens is that the batch with the greater amount of yeast uses less of the sugar for reproduction. This means that more sugar is converted to alcohol (which has a lower gravity than water) so when you take a hydro reading it looks as if it has eaten more of the sugar. What has actually happened, is that the batch with the lower amount of yeast at first pitch, has used more of the sugar in the wort to reproduce itself. The result is that there is less alcohol in the beer and it looks like it has under attenuated. Checking both ferment vessels will show there is quite a bit of yeast in both.

    I think the most important thing is to pitch a healthy starter. I always pitch a starter. It doesn't matter if I am using a smack pack or dry yeast or whatever. I used to make 1 litre starters but have recently shifted to 500 ml because I broke my conical flask and am now using a lab bottle. Yeast is said to double ever 2 to 3 hours, so I don't see how increasing the size of the starter to double its size is going to cut fermentation down by much anyhow.
     
  16. MHB

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    Posted 25/5/18
    Problem with rationalisations based on too little knowledge - they can send you a fair way up the proverbial creek.

    How about, yeast cant swim, it relies on Brownian motion to cause a sugar molecule to bump into a yeast cell where it can be absorbed and metabolised, 10X the yeast 10X the chance of a sugar molecule bumping into a yeast...
    Remember that when the amount of sugar available to a yeast reaches a certain threshold of a given time it will go dormant (cost more energy to stay awake than it's getting from its environment).
    The other point to consider is that people who do the sort of research involved in yeast metabolism aren't using hydrometers to "measure gravity" even breweries bigger than craft breweries aren't allowed to use hydrometers to measure alcohol for tax in Australia - they aren't accurate enough. Look up near infrared spectroscopy, or alcohol determination by distillation (standard method).

    So many other things need thinking about.
    If you pitched 10X the yeast, it wont reproduce as much. The population can only grow while ALL the nutrients it requires are available (Oxygen, Fatty Acids, soluble Nitrogen (FAN)…) There is also a simple upper limit in how far yeast will reproduce (around 100Million cells/mL) if there is too much other yeast around it just stops.
    Short answer is a smaller or larger pitch (unless its ridiculously large) will result in a very similar number of cells. That doesn't mean under pitching is a good idea, the ideal pitch numbers are based on the idea that the yeast will reproduce quickly enough to avoid giving other bugs a chance to get too busy, that the yeast will consume all the nutrients it needs (so it stays healthy) and in the process it will remove all or most of some things in the wort that we don't want in there (mostly Sterols and Fatty Acids, some protein...)
    The amount of cells and their health affect a lot of the other processes in the cells, lower pitches makes for more Esters, higher pitches strip more Iso-Alpha out of the beer.

    This without even getting into subjects like population dynamics that determine the average age of the yeast, yeast cells are pretty much immortal, but every time they produce a daughter cell (clone) it leaves a "Bud Scar" this part of the cell wall isn't able to transpire (at least not as well), enough scars and the cell cant function the way we want.

    This isn't Simple! the old sayin "we make wort - yeast makes beer" is a truism. The science behind yeast management is extremely complex and has a huge effect on your beer.

    Here is a pretty useful introduction to yeast management - I strongly recommend it to you
    Mark
     

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  17. golfandbrew

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    Posted 25/5/18
    Fermentis website shows a product called E2U that sounds similiar to what the above claims are. It also looks like this E2U has been around for quite some time but I have never seen it at home brew shops. Would be nice to be able see this research or hear more about it. Hope to see something concrete on this soon.
     
  18. mashmaniac

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    Posted 25/5/18
    Bloody hell I bought 2 packs of marsh mellows for this flaming!!! WTF There's been longer threads on clocks!
     
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  19. Tje

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    Posted 1/6/18
    I'm always curious as to why people bother to wash yeast. Why not just make a larger starter and harvest from that? A lot less messing around.

    I crash cool, remove most of the starter beer, transfer to a smaller container to minimise headspace and store it in the fridge until it's time to make a new starter. I've got at least 10 uses out of one strain of yeast without any noticeable changes and that was left in the fridge for about 2-3 months before pitching into a new starter.

    Saves me a heap of cash and time.
     
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  20. thumbsucker

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    Posted 1/6/18
    I never hydrate my yeast :eek: to the shook of many.

    The reason is that that the person who taught me to brew is the head brewer for New World Distillery here in Melbourne, the makers of Starward Whiskey. My friend was an attended at a brewers conference where a German yeast microbiologist was on the discussion panel. At one point the hydration question came up in the Q&A and after a while the microbiologist getting frustrated with the questions said in a thick German accent "just dump the dry yeast into the wort" So Starward just dump their dry yeast into the wort (Starward are however moving towards culturing yeast themselves to reduce yeast cost).

    Does it work, yes is it best practice proven by peer reviewed journal published research papers rather then word of mouth that I cannot say.

    I do it because it removes a few more tasks I need to do to get my beer up and running.
     

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