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Thread: Yeast Generations

  1. #1
    Join Date
    May 2007
    Posts
    12

    Yeast Generations

    Hey everyone,
    I'm still relatively new to commercial brewing and I'd like to know how many yeast generations people are using before starting with a fresh propagation culture. This is assuming the viability and health of the yeast is deemed acceptable from batch to batch.

    I planned, somewhat arbitrarily, to stop at 10 generations, although I'm currently very happy with my results going on 15 generations.

    Thanks very much for your input!
    Kevin

  2. #2
    Join Date
    Mar 2003
    Location
    Pittston, PA.
    Posts
    155
    Keep your fermentations clean, keep your yeast happy, practice good yeast harvesting/handling/pitching, and you should never need a "fresh propagation culture".

    Heresy, I know, but it's the truth.

  3. #3
    Join Date
    Oct 2002
    Location
    Richmond, VA
    Posts
    227
    I'm with you, Guy! I got a British ale strain from Brewing Science Institute back in March and it's still rockin' after...what?...23 generations. No discernible flavor changes and I haven't had a single problem with fermentation from batch to batch - still hitting all the numbers and still fermenting over the same amount of time. This yeast strain is a high-floc strain and there hasn't been any change in clarity. And, frankly, I've kind of beat the shit out of this yeast. In some cases, it sat in cold storage for about two weeks and started up right away with the next batch. I've simply fed the yeast some wort while in storage. The only time I've bought another yeast strain from BSI was for a special batch with a different yeast culture.
    Mike Hiller, Head Brewer
    Strangeways Brewing
    2277-A Dabney Road
    Richmond, VA 23230
    804-303-4336
    www.strangewaysbrewing.com

  4. #4
    Join Date
    Aug 2005
    Location
    Nashville, TN
    Posts
    258

    yeast generations

    HI:
    This is a good questions. I remember seeing an article (many moons ago..) in The New Brewer, the authors title was :Yes, Virginia, I'm at my 1000th Generation, or something like it................

    First, you know what endfermentation degree you have, meaning how low your yeast is fermenting. Next, you noted every batch pitching with a number.

    Use only the freshest yeast for pitching, meaning from your last brew. As a rule of thumb, for every 5 gal bucket you pitch, you get up to 5 buckyets back. We pitch with ~ 18 mio yeast cells/ml; which is about 18.5 lbs yeast into a 7 BBL batch.

    We pay much attention to the pH of our pitching yeast. W1056 Ale yeast ferments to about pH 4.5. Now, that's where we get our fresh pitch yeast from. And, of course, SMELL you yeast, that's QA # 1.

    Also, keep your yeast at your yeast bank (White Labs for example..) and if you need a pitchable amount, they will have it for you.

    OK, now:

    ..........EF* (endfermentation degree..) or FG
    ..........#'s already pitched
    ..........pH
    ..........smell and visual observations

    Did you know your pitching numbers, i.e., how may mio/cells ml you pitch?
    If not, get a microscop and do that test, is VIP.

    Cheers,

    Fred

  5. #5
    Join Date
    Dec 2008
    Location
    Williamsburg, Va
    Posts
    135

    Still working it up.....

    In my attempt to get more generations out of my yeast I'm using kegs, cleaning with Chlorine Dioxide (activated by the acidic pH of the yeast), then feeding with sterile wort from a recent brew stored in polypropylene containers that've been autoclaved. I'm hoping to get at least 20 generations. I only use one yeast strain now (US-05) for all beers but I have to use hoppy yeast for hoppy beers which is a pain. I'm blathering.....As it stands right now I only get a couple generations. I'm still working on building a yeast bank. Any tips? Anyone use the Sabco or GW Kent kegs with removable spears for yeast storage?

  6. #6
    Join Date
    Mar 2004
    Location
    Greeneville, TN
    Posts
    230
    Geoff et al,

    The quest for more generations alwasy seems to me to be about cost cutting. In the packaging workd we are all about that extra 1/4 of a cent per beer so we look to save money on expensive yeast pitches.

    One of the reasons I took AleWerks to dry yeast was because the cost savings were there. I could run less generations and start my yeast over sooner to preclude any "possible" yeast health issues. It makes a huge difference when you are paying $500 per wet pitch vs $60 with dry.

    I would love to be the guy that got 40+ generations out of my yeast but just dont want to gamble with that anymore. I

    In the pub world our costs are less relevant. If I pitch a brand new package of dry yeast in a 10bbl batch at River Company then my cost is well borne by the fact that I have 31 cents of beer and I charge $3.75 a pint for it. TO me it makes the requirement to maximize the generations a moot point and allows me to have a very broad spectrum of yeasts in play.

    Don't get me wrong I will be reusing my yeast to a certain extent but not anywhere near what i was at AleWerks.

    Mike
    Mike Pensinger
    Chief Brewer
    Holston River Brewing Company
    Bristol, TN

  7. #7
    mic_mac Guest
    Just thought I'd pitch in on this . . . "pitch in" - ha! - sorry

    Anyway, we're not quite yet brewing in-house & not finally decided what to do about yeast, but I've helped out at one UK brewpub where they used one ale yeast, brewing 15 UKBbls generally once a week, no acid-washing, no propagation, IIRC, no yeast storage even!

    They had 2 adjacent open-top FVs & they would simply scoop sufficient yeast off the top of the fermented beer & into the clean FV ready for that day's brew.

    I'm not advocating it, but it worked for them & it felt like it was the way it had been done for millenia, which seemed cool. They also used one hop & a very small range of malts (pale, crystal & choc IIRC) but made a great range of UK styles from such a limited palate.

    I was really impressed with their confidence & the simplicity of their setup (they also racked into CO2 blanket-pressure grundys, which many UK brewpubs would refuse to do for fears over CAMRA reprisals! - they just didn't tell anyone & the beer was great, so what's the problem?).

    My other yeast regeneration story is about the 220 year-old regional brewery I used to work at. I was told that the yeast was centuries old, having come originally from a London brewery (Mann Crossman & Paulin). When I joined the brewery in 1998 they had recently moved from using a yeast press & trolleying blocks of yeast around, to using a slurry tank system. But the same multi strain yeast was being used (the yeast analysts stopped counting as there were so many mutations in the sample we sent them).

    We acid washed it occasionally, but basically this was the same beast that had been making beer for centuries.

    It's been suggested that this yeast now roams the world, being sold from yeast labs (as a Thames Valley strain?) but to me, the flavour & fermentation characteristics described are wrong, so I have my doubts.

    The brewery itself sadly closed, but some of the museum-pieces & the magical yeast were moved to a new home.

    Hoppy New Beer folks!
    Cheers
    MikeMcG
    http://www.betwixtbeer.co.uk

  8. #8
    Join Date
    Dec 2008
    Location
    Williamsburg, Va
    Posts
    135

    damn

    I'm envious right now Mike.......damn it...haha!

  9. #9
    Join Date
    Mar 2003
    Location
    Pittston, PA.
    Posts
    155
    I know my thoughts go against the conventional wisdom, so I'll just throw some ideas out there for consideration.

    The source of a "fresh" culture is yeast sitting on a slant in a refrigerator. That yeast came from a brewery fermenter somewhere with multiple (dozens? 100s? 1000s?) of pitchings behind it. There's nothing new or special about it.

    Mutations simply don't happen in a proper brewery fermentation in numbers anywhere close to being significant. If one or 2 cells per billion (per trillion?) undergo a genetic mutation, so what? It's an exceedingly rare event and is certainly far outnumbered by bacteria and wild yeast.

    A yeast population never gets old. Any yeast slurry will always contain 50% 1st generation cells, 25% 2nd generation cells, 12.5% 3rd generation cells, 6.2% 4th generation cells, etc. It's simple mathematics.

    Your yeast is happiest and healthiest when fermenting a well-made wort. Keep it clean, wash when needed (phosphoric works fine, I'm too old-fashioned to use anything "chlorine"), don't let it get zinc-deficient, aerate properly, harvest and pitch quickly, and it'll do well. Certainly better than the cells sitting dormant on a slant or pushed to grow in a propagator.

    Any other Joe Owades disciples out there?

    ---Guy
    Last edited by pennbrew2; 12-31-2008 at 08:32 PM.

  10. #10
    mic_mac Guest
    Quote Originally Posted by pennbrew2
    I know my thoughts go against the conventional wisdom . . .
    Maybe they go against conventional wisdom, but they sound like practical wisdom to me.

    Quote Originally Posted by pennbrew2
    Mutations simply don't happen in a proper brewery fermentation in numbers anywhere close to being significant.
    If one or 2 cells per billion (per trillion?) undergo a genetic mutation, so what? It's an exceedingly rare event and is certainly far outnumbered by bacteria and wild yeast.
    IIRC, the lab that analysed the yeast from the old brewery I wrote about said that there were a few main strains in their ancient mixed strain; then maybe 15 sub-strains of these in noticeable numbers; then smaller quantities of endless other related strains. But given that the yeast character was a significant part of their beers' qualities & there were no significant problems, PennBrew2's question " . . . so what?" stands

    Quote Originally Posted by pennbrew2
    Your yeast is happiest and healthiest when fermenting a well-made wort. Keep it clean, wash when needed (phosphoric works fine, I'm too old-fashioned to use anything "chlorine"), don't let it get zinc-deficient, aerate properly, harvest and pitch quickly, and it'll do well.
    When I moved from the ancient ale brewery to a modern lager micro, one of the German brewers was very sniffy about my old brewery's acid-washing the yeast, saying it was now seen as bad practice. I can't remember exactly what he recommended instead though? - I suspect simply a new propagation from a clean source.

    Quote Originally Posted by pennbrew2
    Any other Joe Owades disciples out there?
    I don't think he's very well known over here (I knew the name, but couldn't place any of his many achievements!) but his 2005 obituary made it into one of my least favourite UK newspapers
    http://www.telegraph.co.uk/news/obit...oe-Owades.html

    On yeast - what teachings would his disciples follow?
    cheers
    MikeMcG

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