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Splitting Yeast Packs (in Pictures)

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Wolfy

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The information here is my take on the popular technique Tony posted here and here some years ago, credit also to ex-forum-member haysie, who was the first person I swapped 'splits' with.

Advantages of splitting yeast packs (this way):
  • Simple and easy.
  • Minimal cost or equipment outlay.
  • Saved yeast is 'virgin' or 'generation 0' (hence should not be contaminated or contain mutations).
  • A store-purchased packet of yeast can be used for multiple batches of beer.
  • Stored 'splits' take up very little room.
  • 'Splits' are easily swapped and shared with others.
Disadvantages of splitting yeast packs (this way):
  • Minimal cost for equipment (vials, test-tubes or sample-jars).
  • Starters are required since the yeast-pack is split multiple times.
Equipment required:

The only specialty equipment required (compared to using a full yeast-pack) are some vials to store the 'split' yeast in (see note at end of this post).

Step 0: (optional)
If using a Wyeast pack (as per the pictures here), smack the pack and wait for it to swell, this provides more liquid to split and 'revives' the yeast which should mean it will be viable for a longer period when stored.

Step 1:
Sterilize the sample containers, if they are supplied sterile ensure that the caps are not opened until you are about to use them.
If re-using vials, an autoclave/pressure cooker is the best way to sterilize them, otherwise try the Tyndallization process or simply boiling them for a time.

Step 2:
Working in your draught-free, clean and sterile as possible yeast 'laboratory', wipe the yeast-pack and scissors with alcohol and carefully snip the top-corner of the pack.

Step 3:
Pinch the snipped-corner to form a funnel and carefully decant the yeast-liquid into the sterile vials.

Step 4:
The size and number of 'splits' you make depends on the package size (see note below), how fresh the pack is, how many samples you want to save/swap, and the size of your vials. Here I am making 4x 12ml 'splits'.


Step 5:
Label the vials (and optionally seal the caps using parafilm/tape).


Step 6:
Store 'split' samples of yeast as cold as possible in the fridge (but do not freeze it), after a short time the yeast will settle.


Step 7:
Swapping yeast 'splits' with other brewers allows you to obtain and use other strains to use without additional expense.

('Splits' stored in 10, 12 and 30ml vials are shown above)

This technique works equally well for WhiteLabs vials - which contain about 35ml of liquid and 100billion cells.
Wyeast Activator packs (shown in pictures here) should have about 100billion cells in 125ml of liquid.
Wyeast Propegator packs should have about 50ml of liquid and 25billion cells.

Note about vials, sample-jars or test-tubes
Most people use laboratory-type sample containers, vials or test-tubes but most any container of suitable size and material can be used.
Vials made from autoclavable polypropylene means that they can be heat re-steralized and re-used.
I like to use the 15ml test-tube type containers shown above, but any vial/test-tube/sample-container from about 7ml up to 30 or even 50ml can be used.

To determine the number of yeast-cells in the split and remaining in the pack
First estimate calculate the number of viable yeast cells based on manufacture date (via MrMalty calculator).
Divide this number according to the volume of your splits and yeast-pack type.
Eg: My 1 month old Activator pack should have about 75billion viable yeast cells in 125ml of liquid, hence the 12ml 'splits' should have about 7.5billion cells each, and the remaining 80ml should contain about 48billion cells. The 48billion cells remaining in the pack is more than enough to pitch directly into a 2L starter (which is then pitched directly into a 24L 1.038 Ale).

Storing 'splits'
Yeast 'splits' should be stored in the fridge at as cold temperature as possible (but not frozen) and should be viable for at least 6 and up to 12 months.
In theory it should be possible to replace some/most of the wort/nutrient liquid with sterile-glycerin and freeze the 'split', which should (in theory) greatly prolong the storage time (by years) - however I've not tested this theory yet.

Using 'splits'
Due to the smaller number of yeast cells a starter will be needed.
It may be possible to pitch larger fresher 'splits' directly into a full volume (1.5 - 2L) starter, however most splits, especially if they are smaller volume (like mine) or older (more than 1 month old) a stepped-starter will likely be required in order to grow pitchable quantities of yeast. The size and number of steps required will depend on how much viable yeast is estimated to remain, which in-turn depends on the volume and age of the 'split'.
 

ben_sa

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Awesome work Wolfy. Ive been AG brewing for about 12-18 months and JUST about to venture into the big scary world of liquids lol.

Cheers!
 

troopa

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Awesome as always Wolfy
I gotta say your 2am post are always the most informative :D

Just a quick one though are you still getting your lab supplies from livingstone or have you got(Or know of) a local SE Melb supplier you can drop into and pick up?

Also it would be great to have a dedicated regional swap sticky as well (Which im sure has been asked for before)

Tom
 

Wolfy

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Just a quick one though are you still getting your lab supplies from livingstone or have you got(Or know of) a local SE Melb supplier you can drop into and pick up?

Also it would be great to have a dedicated regional swap sticky as well (Which im sure has been asked for before)
I often drive to Science Supplies in Mitcham, and ProSciTech is worth checking out too.

Yeast is often swapped at the Case-Swaps and I presume monthly home-brew club meetings would make a good swap-venue. There is a Yeast Slant Register article, however I'm not sure it gets much attention, you could try to make a yeast 'split' swap register, but I'm surprised at how few people appear to be interested in such a thing.
 

Wolfy

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After splitting the 4x12ml vials and pitching the remaining (approx 80ml) yeast-slurry into a 1.5L starter, the starter was grown on the stir-plate for a 36h then left to ferment/settle for 12h before taking this photo:

The gravity is about 1.005, it smells/tastes like it should and visually there is a good amount of yeast (somewhere around 150billion cells +/- 50%) so it should be ready to be pitched (tomorrow) into a 24L batch of 1.038 English Ale.
... the splits are in the fridge ready for future use or swapping.
 

Crusty

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Great info for everyone Wolfy, top job. Following your advice, I smacked a Wyeast 1272 & let it sit at room temp for 3 days making sure it was fully fermented out. I probably could of used it on day 2 but waited the extra day. I boiled my 30ml vials for 10mins to steralize, let them cool & divided the wyeast amongst the four vials & put them in the fridge. When I am ready for my starter, I take a vial from the fridge & allow it to come to room temp, usually about half a day. Whilst this is happening, I get 200g LDME & add it to a 2l flask & top up with warm water to the 2l mark. When fully dissolved, I decant off 600mls to a 1lt flask & boil both flasks for 10mins or so to steralize. I boil with some foil on top of both flasks. I then take them to the shed & let them both come to room temp. Once at room temp, I add one of the 30ml vials to the 1lt flask & add the stir bar & leave it on the stir plate for a full 24hrs. After 24hrs, I tip the whole starter into the 2lt flask & culture for another full 24hrs. After that, I place the 2lt flask in the fridge to drop the yeast out & take it out of the fridge the next morning & allow it to come to room temperature. Later that day, decant all the liquid leaving just enough to swirl the yeast & pitch the slurry into my beer. I have just done a SG reading of a fermenting beer with my first ever Wyeast split vial & it has come down from 1.049 to 1.013 & the air lock is still bubbling every 5-10mins. My recipe is calling for a FG of 1.012 so I will be getting exactly what I was aiming for.
Four beers from one Wyeast pack, cheers Wolfy.
 

Golani51

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nice work! :beerbang:
Just a quick note here....I prefer to use a sterile fresh syringe and suck up the yeasty liquid rather than just pour it in. Stick the syringe in the sealed pack and extract the liquid, then squirt the required quantity into each tube. Wipe/spray the needle insertion point first though to kill baddies. Clean, no spills, more sanitary.
 

WeaselEstateBrewery

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Nice post, it's great to see how other brewers do common brewing tasks. One question - is soaking the tubes and lids in starsan for a period of time adequate for sterilisation? Same with the scissors and smack lack.
 

thebeemann

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Nice post, it's great to see how other brewers do common brewing tasks. One question - is soaking the tubes and lids in starsan for a period of time adequate for sterilisation? Same with the scissors and smack lack.

Starsan sanitizes not sterilizes - 2 different things , autoclave tubes etc to sterilize you can use a pressure cooker, and use starsan on the scissors and smack pack , saying that you could try just using starsan you might get away with it a few times its up to you wether you take the risk, i personally wouldnt .
 

Golani51

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Starsan sanitizes not sterilizes - 2 different things , autoclave tubes etc to sterilize you can use a pressure cooker, and use starsan on the scissors and smack pack , saying that you could try just using starsan you might get away with it a few times its up to you wether you take the risk, i personally wouldnt .
It is cleaner than just pouring it. When you pour it, a certain amount 'rolls' over the tip of the bag and comes into much greater contact than just a needle piercing a bag (no- one can argue with this point, and if you do, you are wrong). There is being clean and there is overkill. I don't think there is any real risk.

I make cheese as well and am yet to suffer the consequences. It is pouring some yeast into a tube, not open heart surgery.
 

chefsantos

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nice work wolfy . you are the guru of yeast :)
 

Golani51

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Yeah i do get carried away , its my Medical training ( Ambulance officer / trainee intensive care paramedic ) :p
Aerodynamicist here. My mind was focused on the flow regime of the yeast out of the pack. You must have a nice supply of swabs and syringe filters then.
Where are you based?
 

thebeemann

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Aerodynamicist here. My mind was focused on the flow regime of the yeast out of the pack. You must have a nice supply of swabs and syringe filters then.
Where are you based?
Country South Australia , i was going to ask the boss if i could have the out of date blood tubes for yeast as we throw them in the bin , unfortuanatly they all have anti clotting goo in them so dont know how they would go , no comment on the supply comment :ph34r:
 

peterl1981

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great post wolfy, great information, i will be giving this a go very soon but i might use sterile-glycerin and freeze them... as i dont know of anyone to swap with...

thanx again wolfy
 

peterl1981

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hi all,

Anyone know where in to get sterile-glycerin from????

in melb or online

cheers
lynchman
 

Dazza88

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I sterilise glycerin by autoclaving it in a test tube in a pressure cooker.


Can you do that? Or similar . . .
 
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