# MFG dates



## supertonio (2/2/14)

Hi,

After having read many posts on this wonderful website it is now time for me to finally ask a question and post something.

I have decided to start splitting wyeast packets ( as you can see I'm in Scotland so better reinforce the sterotype of being tight with money) but I have a couple of questions about labelling them.

If I smack a wyeast pack and then split it should I label my vials with the MFG date on the pack or the date that I fill the vials. I am assuming that once/if the pack has swelled it will then be more viable ( compared to being 'unsmacked')

Also, if I were to get to my last vial and to save even more money I then made a starter and split this down should I label the MFG date as being the date the starter finished and was then split?

Any help is appreciated.

Scott


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## rehabs_for_quitters (3/2/14)

The first Question it depends on how you are going to split it, if its directly from smack pack I would use manufacutre date, personally I would make a starter to improve yeast viability and volume first then split that and use the date of the starter, which kind of answers the second question,
Nothing wrong with recycling


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## Yob (3/2/14)

other ways to split and store

Lets Freeze some Yeast Thread 

Further Freezing info

Splitting Yeast Packs - In Pictures

Any which way you go, you are going to require a starter at the end, as suggested above, doing so from a starter to begin with is best practice as you can assume a better vitality, this way you can use the date of storage to label.

:icon_cheers:


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## supertonio (3/2/14)

I picked up the idea from the thread on splitting packets which was really good. I have been making starters already but as its the first time I'm splitting a pack I'll just make starter and split it down regardless of the date on the packet.

As long as I know how to date them then I can keep track on my 'supplies' better.

The recycling aspect makes it easier for me to justify to my wife why I need to keep yeast in the fridge!!


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## rehabs_for_quitters (3/2/14)

Just explain the health benefits of brewers yeast and that your doing it for her, I have yeast in two fridges in glass jars and also 2 of each strain I've used yeast frozen in glycerine in the freezer if I need to start some more up,

Seems a bit tight but I actually quite enjoy getting the lab coat out which is the main reason I do it


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## carniebrew (3/2/14)

Just to show the benefit in numbers in case anyone works better that way. Let's say you have a new Wyeast pack from Dec 25, 2013 (go with me here, maybe they're buddhist). Yeastcalc tells you today that's 70% viable. If you split it today into two test tubes, you have 35b cells in each, with a mfr date of Dec 25, 2013. This can be a bit confusing, as you might be thinking to use 35b as your starting point when using a calculator in a month's time to pitch the 2nd tube, whereas you should be using 50b, as that's technically how much yeast was in your 'split' on the date of mfr.

Regardless, 35b is a low starting point...if you did a starter with tube 1 today, even a 2l starter would only make 147b cells with intermittent shaking...not enough to pitch on 19l of 1.050 ale. It'll be worse of course for tube 2, which you may not use for a month, by which time it's down to 27b viable cells.

What you could do instead is pitch your 70b into a 2l starter, which with intermittent shaking will build it up to 214b cells. Then you could split that 3 ways, roughly 70b in each split, and put a mfr date of your starter, giving you a lot more viable cells to work with from the 3 splits when you're ready to do so. For example, a month after your split, each split will still have 52b viable cells, enough to get 180b cells out of a 2l starter with shaking (which is just about perfect for pitching on 19l of 1.050 ale).


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## supertonio (3/2/14)

It does get a bit confusing for me when I'm thinking of splitting and then using at a later date because brewers friend told me that a pack of yeast I have at the moment is 0% viability. 

I have since came home from work tonight to find it nicely swollen after smacking last night. It will be put on the stir plate tomorrow and then split once ready. 

Am I right in saying that best practise for any subsequent vials that I keep would be for me to step up to an adequate pitching amount regardless of my mfg date I label then with.


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## rehabs_for_quitters (3/2/14)

You'll get better yeast health by stepping it up, what I do as I use white labs is first brew I make a starter, then split a little off and freeze that bit as an archive, the good thing with whitelabs is the containers are spot on for freezing yeast and they are pre labeled just got to date them then pitch as I prefer second generation yeast as it seems to me to produce a lot more yeasty goodness flavours,

then I wash the yeast slurry and store in jars under sterile water to pitch later in the fridge, then next brew day take the jar out of the fridge shake a few times while its coming up to pitching temp then pour into fermenter on top of wort,

Never had a slow starting ferment or any dramas this way, I have used yeast that been stored this way up to around 7 months after first use, keep it in the fridge stored under sterile water and it's easy to handle, just means you need a bit more space in the fridge, then if I need another batch I thaw a yeast popsicle and build up another starter and around we go again


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## carniebrew (3/2/14)

supertonio said:


> It does get a bit confusing for me when I'm thinking of splitting and then using at a later date because brewers friend told me that a pack of yeast I have at the moment is 0% viability.
> 
> I have since came home from work tonight to find it nicely swollen after smacking last night. It will be put on the stir plate tomorrow and then split once ready.
> 
> Am I right in saying that best practise for any subsequent vials that I keep would be for me to step up to an adequate pitching amount regardless of my mfg date I label then with.


I found the same with Brewer's Friend, anything over about 150 days old is immediately assumed to be 0%, which is rubbish. I personally use Yeastcalc, the original site is down, but it's currently being hosted here: http://www.cheapmonkeys.com/yeastcalc/

It told me a Wyeast pack of 3068 I had was 28% viable, rather than the 0% from brewer's friend. I put the 3068 into a 1l starter last week and it went nuts as expected, I then stepped it up into a 1.5l starter a couple of days ago, and I have a truckload of healthy yeast. If I'd relied on Brewer's Friend then technically I should have nothing.


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