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Thread: Handling partial amounts of dry yeast

  1. #1
    Join Date
    Oct 2018
    Location
    México
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    10

    Handling partial amounts of dry yeast

    Dry yeast packs tend to come in either 11 g sachets or full 500 g packs. The former are unwieldy to start mayor batches of big beers but 500 g can be a bit much when only 250 g or 300 g are needed. Instructions heavily emphasize that yeast loses viability as soon as the pack is opened and even if quickly vacuum sealed they are useful for like 2 weeks at most.

    What part of the air is what causes opened dry yeast to go bad, the oxygen or the moisture? Can handling yeast packs in a glove box with a nitrogen atmosphere prevent this issue?

  2. #2
    Join Date
    Apr 2015
    Location
    Lakewood, CO
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    55
    We routinely use partial packs on our 3bbl system. We only need ~250g per batch, so we save the rest in the cooler. I've kept a pack for at least a couple months without noticing significant visibility issues for any of the strains we use. I squeeze as much air out as I can, and tape the pack shut for later. YMMV, of course.

  3. #3
    Join Date
    Nov 2013
    Location
    Chicago IL
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    35
    Quote Originally Posted by spetrovits View Post
    We routinely use partial packs on our 3bbl system. We only need ~250g per batch, so we save the rest in the cooler. I've kept a pack for at least a couple months without noticing significant visibility issues for any of the strains we use. I squeeze as much air out as I can, and tape the pack shut for later. YMMV, of course.
    I've been wanting to do this also, are there any fears of contamination? Would you need to sanitize the Ziploc bag and pour it in the bag in a clean environment?

  4. #4
    Join Date
    Apr 2015
    Location
    Lakewood, CO
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    When I open a new pack, I typically wear nitrile gloves, and sanitize (with fresh Star-San) my gloved hands, a pair of scissors, and the outside of the yeast brick near the top flap. I cut open the pack with the sanitized scissors, pour in the pitch, and fold the top of the pack over a couple times like a bag of chips. Then i use the ubiquitous blue painter's tape to hold it shut, and mark the date i opened it. Before I reopen it, I use gloves and I respray the outside of the pack in case dust settled on it. Haven't had any contaminations thus far.

    Edit: I forgot they're using zip-top bags now. So you don't even need the tape. Just partially close the zip, squeeze the air out, finish sealing the zip, and you're good to go. I still roll and tape the flap to keep it compact, and to write the date on the pack.
    Last edited by spetrovits; 10-30-2018 at 08:31 AM.

  5. #5
    Join Date
    Oct 2018
    Location
    México
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    10
    Quote Originally Posted by spetrovits View Post
    We routinely use partial packs on our 3bbl system. We only need ~250g per batch, so we save the rest in the cooler. I've kept a pack for at least a couple months without noticing significant visibility issues for any of the strains we use. I squeeze as much air out as I can, and tape the pack shut for later. YMMV, of course.
    This is cool to know, I can live with a month or two of yeast life. Thanks for the tip.

  6. #6
    Join Date
    Jan 2019
    Location
    Montreal, Quebec, Canada
    Posts
    16
    Lallemand recently revised the technical data sheets for all of the brewing strains. If the opened package is re-sealed under vacuum immediately after opening, yeast can be stored below 4C° (39°F) until the indicated expiry date.

    Storage under vacuum is ideal, but if you are not able to vacuum seal then remove as much air as possible and make sure that it is in an airtight container. For example, tape the open pack shut and then keep it in a ziploc bag or tupperware (or both).

    No need to sanitize the ziploc bag before storing the yeast. There is little risk of contamination as long as there is no moisture. Bacteria and wild yeast cannot grow and multiply in the absence of water. Use good sterile techique when opening and handling the bag, of course, but you can rest assured that if you even if you introduce a few bacteria or wild yeast cells it will not multiply and become worse if it is stored for an extended period.
    Lallemand is a global leader in the development, production and marketing of yeast, bacteria and specialty ingredients.

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