Let's Freeze Some Yeast

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Midnight Brew

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Coalminer, I think you numbers are close to mine.

Firstly, always make a starter before adding them to vials and the freezer, otherwise you are freezing less ideal yeast while creating a bigger task for the yeast when it comes to reviving. Secondly, the numbers are always going to be ball park estimations. Yeast calculators are great to aid this and will get you numbers that give you a healthy ferment if you have a rough idea on numbers +/- 10%.

To answer your second question, yes you can assume 100% and 80% viable when thawed (I think it could be closer to 90% but I have no evidence nor microscope).

When I first started freezing, I tinkered around with the numbers a bit to try and keep record how many cells were in each vial, based off the starter size. Now I go with a far easier and what I believe to be more accurate. 3.5-4 billion cells per ml.

I use 15ml vials and by the time the yeast is in there with some water and glycerine it takes up around 40-50% of the vial so 6-7.5ml of yeast. Multiply whats in your vial by 3.5 or 4 and thats how many billion you have. Example: 7.5*4=30 billion cells, minus 20% room for error and thaw = 24 billion cells.

24 billion cells into a 200ml starter @ 1020 to wake up then whole starter into 1000-1500ml starter @ 1040 usually gets me to where I need for the ales I make.

Also another handy tip is to keep some old pasta sauce or glass juice bottles. I like to add an extra 5L volume to my brew days when making something around 1040 and use that as starter wort.
 

Coalminer

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Coalminer, I think you numbers are close to mine.

Firstly, always make a starter before adding them to vials and the freezer, otherwise you are freezing less ideal yeast while creating a bigger task for the yeast when it comes to reviving. Secondly, the numbers are always going to be ball park estimations. Yeast calculators are great to aid this and will get you numbers that give you a healthy ferment if you have a rough idea on numbers +/- 10%.

To answer your second question, yes you can assume 100% and 80% viable when thawed (I think it could be closer to 90% but I have no evidence nor microscope).

When I first started freezing, I tinkered around with the numbers a bit to try and keep record how many cells were in each vial, based off the starter size. Now I go with a far easier and what I believe to be more accurate. 3.5-4 billion cells per ml.

I use 15ml vials and by the time the yeast is in there with some water and glycerine it takes up around 40-50% of the vial so 6-7.5ml of yeast. Multiply whats in your vial by 3.5 or 4 and thats how many billion you have. Example: 7.5*4=30 billion cells, minus 20% room for error and thaw = 24 billion cells.

24 billion cells into a 200ml starter @ 1020 to wake up then whole starter into 1000-1500ml starter @ 1040 usually gets me to where I need for the ales I make.

Also another handy tip is to keep some old pasta sauce or glass juice bottles. I like to add an extra 5L volume to my brew days when making something around 1040 and use that as starter wort.
Yeah thanks MB I think I am the right track. Won't really know until I use some after my upcoming holiday
 

MHB

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Braukaiser has some very good reading there is a whole section on storing and reviving yeast, go back to the home page and right at the bottom there are few more bits that really should be linked to the above. There is another section under Yeast Growth Experiments.
Somewhere Kai talked about being able to work out approximately how many cells you have by looking at the change of mass in the starter (if you starter changed 1.020 (20points) or 5oP in 1L you have as oP is %WW, 1L of 1.020 wort weighs 1*1.02=1.020kG, about half of that has been converted to bio-mass (yeast) now divide by the average mass of a yeast cell...That's just from memory go do some digging)
Same bit of info is good for making starters, put the gravity you want in Plato (%WW) if you want 200ml of 1.040 (10oP).
200ml (0.2L) at 1.040 weighs 208g (0.208kg) 10% is extract or 20.8g (0.0208kg).Brewmaths is heally hand
Mark
 
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rossbaker

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Hey guys, i finally picked up some vials to give this a go (it's been on the list for ages) . Quick question... Has anyone with a frost free freezer had any luck storing and then refiring these with out doing the whole insulated container thing?
 

Quokka42

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Hey guys, i finally picked up some vials to give this a go (it's been on the list for ages) . Quick question... Has anyone with a frost free freezer had any luck storing and then refiring these with out doing the whole insulated container thing?
Preferable not to use a frost free anything, as they periodically warm everything up to to melt off the frost.
 

Tony121

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Preferable not to use a frost free anything, as they periodically warm everything up to to melt off the frost.
Agree it is not the preferred way, though putting vials in a container with ice bricks or something similar does a pretty good job. I have not had an issue this way, still firing up the little troopers after almost 2 years.
 

portsparky

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You won’t regret it, in the top 3 best things I’ve done in regards to brewing. Just make sure you piece together all the good bits out of the thread. Good luck.
Thanks Tony. It has taken a lot of reading to try and figure out what people settled on as the best method. I'll just have a go at it and see what happens.

I've attached a couple of other pics. Some were successes, some made my significant other very sad.

Successes included cutting down a rack from proscitech.com.au to fit inside our pressure cooker, and using it to sanitise the 50/50 water/glycerine mix in the tubes. However, I did have to promise first that I'd buy a new one if I ruined the machine. The rack got a little soft bit I think it's fine, and it seemed to work OK.

The yeasties seem happy on the striplate from being on overnight. I'll add another 1 L of wort today.

Failures included me thinking Pyrex would be fine on a cooktop.
IMG_20181230_095814.jpeg
IMG_20181229_140239.jpeg
IMG_20181229_174118.jpeg
 

mofox1

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These simple polystyrene boxes work well to insulate against the frost free cycle:


Shame about that Pyrex jug.. while borosilicate does have much lower thermal expansion than ordinary glass, it tends to be less effective with the thicker glass esp when the heat is concentrated in specific locations... That said, I've cracked a flask by trying to dry it off on the cooktop (on low heat). There was just too much heat change too quickly.
 

Tony121

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Thanks Tony. It has taken a lot of reading to try and figure out what people settled on as the best method. I'll just have a go at it and see what happens.

I've attached a couple of other pics. Some were successes, some made my significant other very sad.

Successes included cutting down a rack from proscitech.com.au to fit inside our pressure cooker, and using it to sanitise the 50/50 water/glycerine mix in the tubes. However, I did have to promise first that I'd buy a new one if I ruined the machine. The rack got a little soft bit I think it's fine, and it seemed to work OK.

The yeasties seem happy on the striplate from being on overnight. I'll add another 1 L of wort today.

Failures included me thinking Pyrex would be fine on a cooktop.View attachment 114539View attachment 114540View attachment 114541
Yes a lot of reading, plenty of good info as you get through it though.

One thing to make sure of is putting the yeasties in the fridge for 24-48 hrs prior to putting to sleep in the freezer - my understanding is that it gives them time to expel the water and soak up the glycerine.
 

mofox1

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Yes a lot of reading, plenty of good info as you get through it though.

One thing to make sure of is putting the yeasties in the fridge for 24-48 hrs prior to putting to sleep in the freezer - my understanding is that it gives them time to expel the water and soak up the glycerine.
^this. Also means if you are using insulated vessel in the freezer, you don't end up heating up your other yeasties by mistake.
 

Kev R

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Hi
Quick questions. Where do you get the little test tubes with lids to freeze yeast?
Are the tubs and lids safe in a pressure cooker?
Is glycerine sterile straight out of the bottle?
Thanks
Kev
 

MartinOC

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I got mine from Proscitech in Qld. as part of a bulk buy many years ago.

This is the kind of thing you're after:

Make sure you get polypropylene ones, which can withstand the temperatures inside a pressure cooker. Get the ones with flat bottoms, as they can stand up on their own.

Nothing is guaranteed sterile with glycerine. You make up a 50/50 mix with water & then pressure-cook the vials filled half-way (lids screwed on lightly).
 

zoigl

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Hi
Quick questions. Where do you get the little test tubes with lids to freeze yeast?
Are the tubs and lids safe in a pressure cooker?
Is glycerine sterile straight out of the bottle?
Thanks
Kev
check my shed clear our ad, I have a huge number of unused t/tubes unused.
 

Moad

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reviving ( see what I did there) an old thread. About to spin up some 1968 that's about 5 years old. I can't remember whether to put the glycerine in with the yeast when reviving it. I will decant what I can but from memory a little is good for the yeast
 

Grmblz

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reviving ( see what I did there) an old thread. About to spin up some 1968 that's about 5 years old. I can't remember whether to put the glycerine in with the yeast when reviving it. I will decant what I can but from memory a little is good for the yeast
I use 100ml tubes, my usual process is allow to come up to room temp naturally then chuck the whole lot into 500ml 1035 wort, spin for 3 days crash, decant into 2L 1035 for 3 days, crash decant and pitch, or if in a rush pitch the 2L at "high" adding however much sugar to make up for the 1035, I do use fermaid "O" Not very scientific I know, just seat of the pants stuff. I've seen advice claiming defrosting using warm water to speed up the process is beneficial, have never tried it as what I do works for me.
Good luck with it, I can't remember doing any 5yr old although it's quite possible, been keeping a bank for years but my record keeping is atrocious, I now write the date as well as the strain :rolleyes: fwiw if it hasn't kicked off after 24hrs I ditch it.
 

duncbrewer

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I'm just spinning up a Brett salvaged from a keg. Seems to have some foam on the top and active after 4 days with a top up after 3 days. I'm lead to believe that you need to pitch all of a brett starter as it doesn't settle at all well. It's for a 100 brett Saison.
 
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