I have done my last 40 brews with frozen yeast up to 2 1/2 years with no ill effects,(have trouble keeping up the supply). that is with 12.5 ml glycerine in a 50ml vialAre there any negative effects of having glycerine in the wort? Flavour, yeast health, attenuation etc
I realise that there's only a very small amount of glycerine per pitch. e.g. 5ml per 50ml tube and then that is then diluted in 20 odd litres of wort.
Any effects would most likely be extremely negligible but I thought I'd ask just in case.
Ha ha had to read that a few times , I thought they gave you a up and a binder as wellCalled in to my local pharmacy today and asked if they had any "Vaccine Shippers" they were happy to hand over this 5L one and a 10L, came with half a dozen of the cool gel packs, the coffee cup and the binder (A4) should give you a fair idea of the size, seen some half the size, some way bigger.
Great little freebee and it keeps them out of landfill.
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Any chance of writing up a 'How to' Although I have a feeling there was a thread on thisI have done my last 40 brews with frozen yeast up to 2 1/2 years with no ill effects,(have trouble keeping up the supply). that is with 12.5 ml glycerine in a 50ml vial
( I use 12.5 glycerine 12.5 water and 25ml yeast slurry) Don't forget that you are stepping up 2 or 3 times and decanting spent wort each time so very little would end up in the fermenter as it is water soluble
Glycol?Just one point, I would probably want to use a bit more Glycol. It's the formation of ice that kills yeast cells either by their exploding just like a bottle in the freezer can, or by ice crystals that form like little needles skewering the cells from the outside.
The later effect is most common when the glycol content is too low to prevent slush formation (slush is ice crystals in suspension).
It will depend on the temperature you are storing at (the colder the better) but say you are at -20oC from the following table -
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The 25% glycol in Coalminers method would not be enough, most of what I have seen recommends at least 1/3 glycol (33.3%) and up to 50% for colder freezers.
It is best to keep the frozen tubes in an insulated container (even a 6 pack esky) with a couple of big bricks of gel ice just to keep the storage temperature stable. even smallish temperature changes at close to the slush point can cause ice needles to grow and kill more cells.
Yes I use these. they are autoclavable at 121oCCan you use plastic conical test tubes ?