Freezing Liquid Yeast With Glycerine

[DaveR]

Hi Guys,

Has anyone tried freezing 1st generation liquid yeast. I am abouut to give it a go. Aparently if you freeze with glycerin you won't rupture the cell walls and it will store up to 2 years. If someone has had experience with this method I would love to hear.

http://www.schwedhelm.net/brew/yeast_harv_freeze.html

Cheers,
Dave

 

[pint of lager]

Yes, freezing yeast and glycerine does work as a way to store yeast.

I used washed yeast slurry, see white labs yeast site for washing details, and used a 50%water 50% glycerine solution, boiled to sanitise and then mixed this in to the yeast slurry, waited 24 hours then popped into the freezer. The resulting slurry does not freeze.

When it is time to make a starter, put about a teaspoon of slurry gloop into a starter solution, I used about 1-2 teaspoons gloop into 500ml.

Have been told that a sugar solution also works but never tried this.

 

[DaveR]

Hi pint of lager,

A few questions...

How long have you been doing this & what's the longest you have stored the yeast in the freezer?

What size vials, tubes do you use?

Do you keep the vials in a small esky with freezer blocks to prevent defrosting?

What was your defrost proccess?

Thanks,
Dave

 

[pint of lager]

I have used the stubby method, storing slurry in the fridge under beer, storing washed slurry under water, freezing and finally under sterile water as to GLS method outlined on craftbrewer.

The longest I kept and used frozen was about 12 months.

Used plastic jars that had been bleached and rinsed with boiled and cooled water (would now use iodine as final rinse.) The size was about 200ml.

Nver used an esky with blocks. The jars of frozen slurry lived always in the freezer amongst the hops. The glycerine stops the slurry from freezing.

When time came to warm the yeast slurry up, I removed a teaspoon or two of slurry and put this straight into the starter....nice lot of thermal shock. The jar went straight back in the freezer.

 

[DaveR]

Thanks pint of lager,

I will be using 20ml vials that I got from work. I got 10 of them so they should last me quite a while.

 

[pint of lager]

20 ml may be a bit small, that is only a few teaspoons worth. You could always fill a couple. As I said, I used a 200ml plastic jar, was a small peanut butter jar.

Make sure your samples are well labeled with date and type of yeast stored. Watch out, some texta markings rub off when damp.

If you can, score some petri dishes and salt these away. Use them to make agar plates up for streaking.

If you ever come across a pressure cooker, they are used to sterilise plates and starter wort.

 

[DaveR]

pint of lager,

I can get petri dishes, but the reason that I want to freeze the yeast is too skip the hassle of petri dishes etc..

If I step up from 10ml to 100ml to 1ltr I shoud be fine.

 

[Tony M]

I went to the link that dave posted and this Scwedhelm fellow adds hops to his yeast starters.
Why is it so?

 

[pint of lager]

Three reasons why you would add hops to starter

1. hops are supposed to be a preservative, so they may be helping to retard any infection

2. the yeast in a starter is training to brew, so you want it training to beer, not to just plain old extract

3. if you are tipping the starter solution into your beer, an unhopped addition will lower your overall bitterness

 

[pint of lager]

DaveR, grab some petri dishes now and put them at the back of your brew cupboard.

You may not want them right at this instant, but maybe in the future things will change. You may be working in another job where there are no free petri dishes and decide that culturing is for you.

Grab at least 15 120mm glass dishes, or a stack of plastic sterile dishes.

Cuturing from streaked dishes is the bees knees. You can tell from the dish, it is infected or clean, no inbetween.

 

[Hoops]

DaveR, grab some petri dishes now and put them at the back of your brew cupboard.

You may not want them right at this instant, but maybe in the future things will change. You may be working in another job where there are no free petri dishes and decide that culturing is for you.

Grab at least 15 120mm glass dishes, or a stack of plastic sterile dishes.

Cuturing from streaked dishes is the bees knees. You can tell from the dish, it is infected or clean, no inbetween.

[post="21086"][/post]​

POL

I'm looking at getting some plates from Livingstone in a few days. I was thinking of getting 2 x 90mm borosilicate plates.
Why do you suggest so many plates (15)?
Do you think 90mm would be too small?

Hoops

 

[Kai]

Have been told that a sugar solution also works but never tried this.

[post="20973"][/post]​

Delayed response here, but yes a sugar solution would not freeze but you are adding extra stress on the yeast from the added osmotic pressure so I don't know if that would be a good idea.

 

[pint of lager]

2 petri dishes is not enough.

When you streak up your yeast, you want to do at least two per yeast,and preferably three. If one plate is infected, you have a few more to use.

You may want to have more than one yeast streaked up ready to use.

When preparing plates, it is easiest to make whatever quantity you can fit in your pressure cooker. This means, you always have sterile plates ready to go.

Gauranteed you will break some too.

Originally, I bought 10 60mm plates from livingstone. Not enough and too small.

Livingstone are so cheap for this stuff. Do yourself a favour and buy more.

 

[BrissyBrew]

I have a SSA science supply australia catelogue what are the contact details for livingstone

 

[pint of lager]

Livingstone Laboratory Supplies
106-116 Epsom Road, Roseberry NSW 2018

website