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Yeast starter question

Discussion in 'Homebrewing' started by HopsMatt, Oct 18, 2012.

  1. HopsMatt

    HopsMatt Savant (460) Kentucky Dec 1, 2011

    I did my first starter on Tuesday in advance of my Thursday brewing. I have a few questions before I pitch that I am wondering if someone can answer. I am brewing a high gravity all grain DIPA. I used the San Diego Super Yeast and split the amount between two growlers, so a gallon worth of starter. I am sorry if these issues have already been answered. I have searched many places and have found out many opinions, but no direct answers.

    First, Cold Crashing. What exactly is it, what is the point and should I do it?

    Secondly, do you pitch the full volume? If so, we are doing a five gallon batch so, should I subtract the volume of the starter from the original volume?

    And I guess if I take that all into account with some assumptions, I come to this: I cold crash the starter, pour off a large majority of the liquid in both vessels, shake and pitch the yeast into the wort. Correct any of that where I am wrong.

    Thanks in advance!
     
  2. VikeMan

    VikeMan Champion (750) Pennsylvania Jul 12, 2009

    The point is to avoid getting starter 'beer' in your regular beer, thus diluting/adulterating its flavors, ABV, etc. You do it by putting the finished starter into the fridge for a day or two. Overnight might be long enough for a highly flocculant yeast strain. (I'm not familiar with San Diego Super Yeast behavior.)

    You got it. Though I would describe it as more swirl than shake.
     
  3. mattbk

    mattbk Savant (390) New York Dec 12, 2011

    Cold crashing question. Do people normally make a slightly bigger starter when cold crashing, and if so, how much bigger (eg 10%, 25%, etc). I have to believe that the cold crash won't completely drop all of the yeast in the starter out of solution, and as a result you will underpitch your yeast.

    In a related story, the pilsner I've been making seems to frequently suffer from diacetyl, even with pitching at 50-55 degF, large starters, long diacetyl rests (2-7 days), and 6 week+lagering times. I never cold crashed the starter because of the reason above, and am beginning to think that pouring in the starter 'beer' is the culprit.
     
  4. VikeMan

    VikeMan Champion (750) Pennsylvania Jul 12, 2009

    There will certainly be some yeast left in suspension, but my guess is that if you cold crashed sufficiently, it will be more like 1-2%. I've never increased the starter size because of it.

    I always cold crash my starters and have never had diacetyl in my pilsners (or any lagers). I don't know if pouring in the starter beer could be a cause for diacetyl...I suppose it could if you're dumping in more than the diacetyl rest can clean up. But man, if you're making appropriate sized (big) starters for lagers, I can't imagine dumping those into the beer wort anyway. Why go to all the work of formulating a great recipe, only to add random flavors?
     
  5. I also depends on the yeast strains and if all the sugar has been consumed. Some strains will not floculate well if any sugar is left- other strains fall out as soon as they get cold.
     
  6. mattbk

    mattbk Savant (390) New York Dec 12, 2011

    I guess my concern was that there was a bigger risk of underpitching than risk of off flavors from the starter. When I cold crash, I don't always notice an exact line between "yeast sediment" and "spent wort", therefore, I've been concerned that I'm discarding healthy yeast in suspension. Maybe this is a function of yeast strain as LL says above.

    I can also say that in ales, I never taste any off flavors from pitching the entire starter; I'm assuming this has something to do with primary ferm temp, the yeast strain itself, or both. My current assumption is that I'm creating diacetyl by fermenting the lager starter warm, which the yeast cannot rebasorb during the colder primary lager fermentation.

    Hope this helping the OP with their question, don't mean to threadjack.
     
  7. tngolfer

    tngolfer Aficionado (200) Tennessee Feb 16, 2012

    Lager yeasts can be room temp when making a starter. I actually just read that in BYO magazine last night.
     

  8. Matt,

    You might be interested in reading that Jamil Zainasheff is a proponent of pitching the entire starter when the starter is not too large or aerated. Below are some quotes from his article in Zymurgy entitled “Making a Starter”.

    “Most yeast experts say that when propagating yeast, moving at high krauesen is optimal. The time of high krauesen can range anywhere from a few hours to 24 or more.”

    “I (Jamil) like to pitch starters while they're still very active and as soon as the bulk of reproduction is finished, usually within 12 to 18 hours.”

    “Of course, if you have a large starter volume in relation to your batch of beer or a starter that was continuously aerated, then you probably don’t want to pitch the entire starter into your wort.”

    Cheers!

    Jack
     
  9. yinzer

    yinzer Savant (385) Pennsylvania Nov 24, 2006

    Sorry to add to your angst, but I think that our way of estimating cell count is just a big crap shoot. A vial/packet cell count is 80%-120% of the advertised count. Viability? It can't be the same during the different seasons. I really don't think that the small number of cells that haven't dropped would matter.
     
  10. mattbk

    mattbk Savant (390) New York Dec 12, 2011

    OK. Thanks for the input. HopsMatt, hope this helped...! To summarize:

    1) Room temp starters should be OK for both ales and lagers.

    2) Cold crash and decant may be less critical for small starters and/or ales; probably more critical for large starters and/or lagers (by definition you usually have a larger lager starter for the same gravity).

    FYI, my starters always go on a stir plate, so yes, they are definitely aerated.

    Next pils batch I'll try cold-crash/decant and report results (if I remember - dammit, lagers take forever.)
     
  11. HopsMatt

    HopsMatt Savant (460) Kentucky Dec 1, 2011

    Thanks for all the help guys! I ended up cold crashing and just using half the volume in each growler. It's already fermenting and it's only been a couple hours. :)
     
  12. VikeMan

    VikeMan Champion (750) Pennsylvania Jul 12, 2009

    If you're going to the trouble of cold crashing, you can (and IMO should) use a lot less than half the volume of the spent wort. I leave just enough to be able to swirl the yeast into suspension for easy pouring when pitching.
     
    good_gracious likes this.
  13. Are you confident that it is diacetyl and not DMS? How long is your boil?
     
  14. You can reduce diacetyl production by pitching at a lower temperature, so that is at 45F or so for a 50F lager fermentation. Cold crashing is fine for lagers, as the starters are large and I don't want that large amount of aerated spent wort in the beer, and it is less stressful on the yeast if they go in colder than the wort.

    Edit - use plenty of O2 also, you want to get to around 10 ppm or a little more, air only gets you to 8 ppm.
     
  15. mattbk

    mattbk Savant (390) New York Dec 12, 2011

    Boil is 90 minutes. Buttery, not vegetal. Although I will admit I am very very sensitive to diacetyl, much less so to DMS.

    For this last batch I got down to about 70 with my chiller, then placed in the controlled fridge at 50 overnight, then pitched the starter at 50 the next day. I'll try pitching a bit lower next time as well.

    I shook the fermenter pretty good before pitching, but it's possible the DO was a bit low since I'm guessing it would be harder to dissolve in the oxygen when the wort is that cold. The fermentation was definitely more sluggish than normal, I think it took me almost 2 weeks to get to 75% of FG; which is a bit longer than what it normally takes me. I could definitely attribute this to low DO.

    We're getting pretty off topic here: but recommendations on best way to add O2 directly? Thanks guys.
     
  16. Best way for O2 is an O2 tank, regulator and a stone.

    For lagers I use an chiller with tap water, and once the temp gets below 100F, ice water is recirculated through the chiller with a pond pump until it gets to 45F.
     
  17. yinzer

    yinzer Savant (385) Pennsylvania Nov 24, 2006

    I use the setup where the stone is on a metal tube. That way I can put it in the oven and sterilize it. I also hooked up a flow meter so I know how much O2 that I'm putting in.


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  18. Where did you get the flow meter, where didi you find it and how much should it cost?
     
  19. yinzer

    yinzer Savant (385) Pennsylvania Nov 24, 2006

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