Let's Freeze Some Yeast

Discussion in 'Yeast' started by Bribie G, 2/12/10.

 

  1. gezzanet

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    Posted 8/11/17
    Just woke up a 1084 Irish ale. Mfg date 21 03 17. Smacked on 22 05 17 and split into 5 x 50ml tubes and frozen. Was cold but not always frozen as drawer freezer was moved and left open once. Yep I have to share it with other food.
    So I thought it might be trashed. 50 ml tube it in tap water to defrost then sprayed with starsan before opening and dumping in 1.020 600ml. 1st day not much action by end of day 2 bubbles showing.
    Stir plate turned off to let it settle out of fridge for 2 hours then poured off 500ml top. 100ml yeast slurry poured into 2500ml 1.030. 25 mm foam in the morning then by 6pm this is what it looks like. Seems hardier than I thought. Think I need to mash an Irish red
    IMG_8092.jpg
     
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  2. timmyf

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    Posted 1/12/17
    Moving house soon so was cleaning out the freezer and came across the frozen yeast bank. I've been enjoying the increasing range of dried yeasts for the last couple years so I'd almost forgotten about it. The oldest vial I had was WLP800 at about 3.5 years old. I decided to spin it up and see how it would go.

    IMAG0227 resize.jpg

    Stepped through 200ml of weak wort (~1.020), into 1L of 1.040 and finally 3L of 1.040

    IMAG0228 resize.jpg

    End result about a 50ml tightly packed cake of healthy looking yeast.

    IMAG0254 resize.jpg
     
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  3. Nullnvoid

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    Posted 1/12/17
    Stupid question but does anyone make up the starter wort in advance. Ie I have just started the 200ml but make the rest now ready to go for the following steps?

    Too much risk?
     
  4. Mardoo

    Noob What Craps On A Bit

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    Posted 1/12/17
    Freeze it if you do, and ideally re-boil. I’ve done it without the freezing step, but for this Nervous Nellie, it was a bit nerve racking up to the point I tasted the beer. Technically boiling can leave some encysted bacteria still viable.
     
  5. Nullnvoid

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    Posted 1/12/17
    Good enough for me, I'll make it up fresh as the step requires.
     
  6. Tony121

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    Posted 3/12/17
    This morning I found my beer freezer had been left open the day before and everything in there thawed, including my 40 odd vials of yeast. Everything was still cold but well and truely thawed. I immediately put them in the kitchen freezer whilst dealing with the mess of the other one.

    Hoping for some thoughts here on what to expect. Will they be ok or am I going to have to ditch them and start again?
     
  7. Tony121

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    Posted 3/12/17
    Anyone have any thoughts on this?? Dare say the only way to know is to fire them up but was hoping someone had experienced something similar and can offer an opinion.
     
  8. timmyf

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    Posted 4/12/17
    I'd just relax and not worry too much about it Tony. If they were still cool they should be fine. Not ideal, but fine.

    Mine have always been kept in modern fridge/freezers with defrost cycles that probably push the vials close to thawing. I also had a full fridge blowout about 9 months ago that lead to a full thaw and keeping all the vials at room temp for about two days until I got a new fridge. As you can see in my earlier post-up the page, even after treating my yeast poorly, I still got it to fire up three and a half years later.
     
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  9. Mardoo

    Noob What Craps On A Bit

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    Posted 4/12/17
    Happened to me. All good. I haven't yet had any problems with anything firing up. I did throw out some soup though, but no yeast. ;)
     
  10. Tony121

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    Posted 4/12/17
    Thank you both, my blood pressure has come down slightly.

    From now on ice blocks are banned from my beer freezer!
     
  11. kcurnow

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    Posted 29/12/17
    Attempting to revive some Trappist ale yeast that I have had frozen since Jan 2015. This yeast has so far travelled from Melbourne to Brisbane and may not have been well frozen in the process so it will be interesting to see if it is still viable. 200ml 1020 starter for starters :). IMG_3292.jpg
    IMG_3293.jpg
     
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  12. Moad

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    Posted 30/12/17

    I went through a stage of canning starter wort but I haven’t been that prepared for a while. You can leave it in the canning jars and have them on hand no dramas. I’m not sure it’s worth the effort though
     
  13. MartinOC

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    Posted 30/12/17
    Agreed. Having stuff in liquid form takes up valuable space, when DME can be boiled-up & cooled in an erlenmeyer in the space of 30 mins.
     
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  14. kcurnow

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    Posted 31/12/17
    So success!!, after three years of being frozen including a period of being unfrozen when being posted up from Melbourne to Brisbane the WLP500 has fires up after 48 hours in a 200ml 1020 starter. I’m pretty happy with this. IMG_3318.jpg
     
  15. Midnight Brew

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    Posted 11/1/18
    IMG_5037.JPG

    Not a NEIPA but WLP004 frozen (w/15% glycerine) on the 30/11/2014.
     
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  16. malt junkie

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    Posted 11/1/18
    wow, I recon @Yob needs to get his butt in gear and light up a really old one(and possibly brew something for swap), but thats damn impressive MB
     
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  17. koshari

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    Posted 11/1/18
    ok quick question, how much LME in 200ml to make a 1020 starter?
     
  18. Midnight Brew

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    Posted 11/1/18
    About 10g. I assume LME is light (dried) malt extract not liquid malt extract, as that would be painful to measure.
     
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  19. koshari

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    Posted 12/1/18
    yep i got dried malt extract, thanks, for the quick reply,
     
  20. Coalminer

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    Posted 13/1/18
    Hi
    Have read this thread twice and have some vials frozen but not yet tried one. My question is how do you calculate the viability of the frozen yeast.

    First question
    when using yeast calculators to build up a pack of yeast for the correct amount for pitching the viability of the smack pack is calculated from the manufacture date, say 1 month old, is 77% and go from there.
    My thinking (may be completely wrong) goes like this:
    Take a new smack pack, say 1 month old and viability 77% and split into 5 vials of 25ml slurry each = 20x77% = 15.4Billion. Viability when thawed 77% less say 20% loss due to the freezing process = 61% so theoretically 20 x 61% = 12.2Billion - at the date of thawing (use that date in calculator instead of original pack date) use this figure to build starter reqd.

    eg Dads Homebrew calculator says 200ml then 1.3L to get 224 Billion for a 1050 23L Ale using the thawing date as viability calculation

    Second question
    If the above is correct how do you estimate the viability of the following:
    Take a smack pack of 1 month old - 77% viable and build a starter to pitch into a brew, but first overbuilding that starter by 100Billion cells. Use whats needed for the pitch and use those 100Billion overbuild cells to split into 5 vials as above.
    Can these fresh cells be considered to be 100% as they have just grown, then be considered as 80% viable when thawed (say 20% loss due to the freezing process)
     

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