What I Don't Understand About Slanting

[Bribie G]

Can you get little freezers - say the size of a small esky ? maybe for use in labs or something? Just a thought.

 

[felten]

Just back to this statement for a moment. If Whitelabs store their commercially packaged yeast under liquid for the intention of shipping to the world and sitting in a shop for 6 months or more, and expect it to be viable to the end user, that gives me faith that I can do the same thing at home with a relatively clean sample taken by top cropping a fermenting wort.

Or is it that any mutation on the strain has already occurred once it hits the beer?

Yeah but they lose ~20% viability a month, they want you to use them fresh.

 

[manticle]

Sorry, a bit :icon_offtopic: Manticle, how long have you been able to store the yeast for like this?

I haven't really counted. I just use the yeast I have on hand that I want when I want. Every time I get a different type of Wyeast, I split some off into clean sterile test tubes with boiled, cooled water, label and store in the fridge. Definitely several months though.

I used to use longnecks before I got my test tubes and used yeast that was several months old with no dramas. I always make active starters which should tell you if something's wrong. Obviously I step up from the test tube amounts first.

Definitely not the best way to store yeast but it's worked well for me so far (and that's a few brews). As with all things i'll probably try slanting one day but I like to move one step at a time, especially when things work for me.

And silo - yes you can top crop, store and use the yeast later. What whitelabs do in their 'yeast lab' and what you do at home are never going to be quite the same though. You definitely can store yeast under liquid - I think what thirsty was getting at is that there are better ways (in response to you asking why would you bother?).

 

[manticle]

Sorry, a bit :icon_offtopic: Manticle, how long have you been able to store the yeast for like this?

I haven't really counted. I just use the yeast I have on hand that I want when I want. Every time I get a different type of Wyeast, I split some off into clean sterile test tubes with boiled, cooled water, label and store in the fridge. Definitely several months though.

I used to use longnecks before I got my test tubes and used yeast that was several months old with no dramas. I always make active starters which should tell you if something's wrong. Obviously I step up from the test tube amounts first.

Definitely not the best way to store yeast but it's worked well for me so far (and that's a few brews). As with all things i'll probably try slanting one day but I like to move one step at a time, especially when things work for me.

And silo - yes you can top crop, store and use the yeast later. What whitelabs do in their 'yeast lab' and what you do at home are never going to be quite the same though. You definitely can store yeast under liquid - I think what thirsty was getting at is that there are better ways (in response to you asking why would you bother?).

 

[Nevalicious]

Well, the frozen yeast bank idea got me all inspired.

I made a little trip over to my local scientific supply place (which consequently, is not at all local, but it doesn't matter, it was in work time...) and stocked up. 30 x 20ml borosilicate flat bottom vials, couple of glass pipettes etc etc. Picked up a mini cooler bag and some gel ice packs from Big Dubs, Glycerin from the pharmacy... I've 3 vials of White Labs on order, fresh from the states. I've read and re-read the frozen yeast bank link. I'm ready!!!

Bring it on!

 

[Thirsty Boy]

TB,

Yes the guide does. What is recommended is the vials are placed in a styrofoam box or small esky with gel ice packs inside to counter the fridge defrost cycle.

Cool - thought i'd flag it just in case it wasn't

Just back to this statement for a moment. If Whitelabs store their commercially packaged yeast under liquid for the intention of shipping to the world and sitting in a shop for 6 months or more, and expect it to be viable to the end user, that gives me faith that I can do the same thing at home with a relatively clean sample taken by top cropping a fermenting wort.

Or is it that any mutation on the strain has already occurred once it hits the beer?

Well, I think its commonly accepted that the viability of those liquid yeast packs starts dropping pretty dramatically as soon as they are packaged, and after 6 months for instance, G&G starts selling them at half price - I think that there really isn't anyone expecting them to be sitting in a shop for six months or more and still be maintaining acceptable viability.

You can look at the MrMalty calculator and get an idea of how fast they drop off... And remember that MrMalty just finished writing a book about yeast with the owner of white labs... So I have a feeling that what he reckons is probably not a million miles from the truth, or perhaps his co-author might have had something to say about it.

And certainly no one would expect to repeatedly re-culture from liquid yeast "packs" that had been stored for months.

People do it, people seem to make it work - but Slants/plates have been repeatedly demonstrated to be the best way (short of cryogenics) to maintain the brewing properties of a given yeast sample in medium to long term storage.

If people are looking for easy, then there are lots of options - if people are looking for the "best" way to maintain a yeast library at home, then slanting is very probably it.

Assuming of course you do it properly.

 

[felten]

You can look at the MrMalty calculator and get an idea of how fast they drop off...

They reckon 20% a month, if you play with the calc you get roughly the same.

 

[[email protected]]

Well, the frozen yeast bank idea got me all inspired.

I made a little trip over to my local scientific supply place (which consequently, is not at all local, but it doesn't matter, it was in work time...) and stocked up. 30 x 20ml borosilicate flat bottom vials, couple of glass pipettes etc etc. Picked up a mini cooler bag and some gel ice packs from Big Dubs, Glycerin from the pharmacy... I've 3 vials of White Labs on order, fresh from the states. I've read and re-read the frozen yeast bank link. I'm ready!!!

Bring it on!

Following through with a bit more detail on the frozen yeast bank (post 110), the guy I have been emailing in the US about this subject has some additional techniques that possibly improve the storage. He doesn't store under the starter liquid as it shown in the link in the post. He advised to pour of all the starter liquid and add a sanitised yeast nutrient water (1 cup with a pinch of nutrient) to allow the yeast slurry to be fluid enough for proper mixing with the glycerin and reduces any sugars left.

I can post all his details here if people would like to see them. There is a fair bit of detail.

Additionally, if you have a chest freezer or even some of the mini freezers (look like bar fridges) these are generally manual defrost and would help in avoiding any cyclic temperatures.

 

[Silo Ted]

According to a 2006 BYO Magazine article, the WL yeasts are now shipped out with an average cell count of 100 billion, a lot more than what I thought to be around 35 billion. With a 20% decrease per month this would still mean there's about 26 billion cells, not far off the previous count. Not bad figures to consider if buying old stock. Also not too far off the previously shipped 35 billion.

I almost bought one of these USB microscopes so me and a mate could look at the cell count on stored yeasts, but many reviews say that they are rubbish, and not even close to the stated specs of 400x. as well as the picture quality being poor. Would a conventional microscope be adequate to view yeast cells, and at least visually estimate cell count? Im very interested to observe the decline in viability with recycled cropped samples, and compare to newly purchased vials.

If brewers are to take samples from an active ferment for storage purposes, isn't this going to be a new generation of healthy cells with a high count per microgram (or whatever the standard measure might be), or will hop & grain debris significantly diminish the count? Mutation aside, Im still unclear as to why you cant just keep culturing crude fresh samples in a series of starters every couple of months to perpetually maintain a yeast bank. Although I guess if you do this often enough to keep your samples viable, the cost of DME and the time involved would be greater than just buying a new vial of reliable clean yeast.

 

[razz]

Following through with a bit more detail on the frozen yeast bank (post 110), the guy I have been emailing in the US about this subject has some additional techniques that possibly improve the storage. He doesn't store under the starter liquid as it shown in the link in the post. He advised to pour of all the starter liquid and add a sanitised yeast nutrient water (1 cup with a pinch of nutrient) to allow the yeast slurry to be fluid enough for proper mixing with the glycerin and reduces any sugars left.

I can post all his details here if people would like to see them. There is a fair bit of detail.

Additionally, if you have a chest freezer or even some of the mini freezers (look like bar fridges) these are generally manual defrost and would help in avoiding any cyclic temperatures.

Very interested abc,please post the details or a link. Thanks.

 

[drsmurto]

Very interested abc,please post the details or a link. Thanks.

I'm also keen to see the extra details. :icon_cheers:

 

[Nevalicious]

I'm also keen to see the extra details. :icon_cheers:

As am I... Cheers

Tyler

 

[argon]

I made a little trip over to my local scientific supply place (which consequently, is not at all local, but it doesn't matter, it was in work time...)

Guess what i'm up to today... sweeet!!

Edit: Oh yeah +1 on the extra details

 

[[email protected]]

A bit more detail as promised. The process is similar to the one that was posted in homebrewtalk but has a little bit more detail and some variations that are worth noting. I admire everyone's enthusiasm in getting stuck into it - it has taking me more than aa month to just start to organise some of the basics!

This is from a friend in the US who is a homebrewer and has experience with culture labs (PhD in bio chem):

My method for creating a frozen yeast bank isn't too difficult. The beginning supplies you need are
-Styrofoam box that fits in your freezer
-Ice Pack
-Glass/Plastic Vials (look for 15-25mL glass vials OR use 50mL Flacon tubes)
-Turkey Baster (stainless steel if you can find it)(or spend the money and buy an electric pipette and 10-15mL pipettes. though that can get pricey)
-a rack to hold test tubes
-a pressure cooker
-glycerin
-something to label with
-sterilized yeast nutrient water
-latex/nitrile gloves
my basic procedure is as follows

-When creating a yeast starter from a new tube/pack of yeast, make a small side starter (400-600mL) with some of the yeast. You can either use this yeast or increase the starter if you want more vials. Cold crash and pour off as much of the starter wort as possible. cover and put back in fridge.

-add approx 10-15% of your vial capacity with glycerin, lightly close cap and sterilize along with turkey baster/pipette tip in pressure cooker to sanitise. Aim for about 20min.

-Let the vials etc cool. Keep the tip of the turkey baster from touching anything.

-Add just enough sterilized yeast nutrient water to the yeast cake to allow you to suck up the yeast in the baster. Trasfer to the sterilized vials, get them full (but remember to leave head room for expansion).

-close cap firmly (if you are not using gloves, or, even if you are, avoid touching the threading on the vial or the inside of the cap)

-invert the vials 10-15 times and then shake to allow glycerin to incorporate in the mixture. appropriately label the vials (I use packaging labels I cut up into small strips)

the info you should have is Yeast Strain, Generation (1st gen- straight from yeast tube/pack, 2nd gen- from a yeast slurry/cake or from a bottle conditioned beer, 3rd gen- yeast cake slurry from a 2nd gen vial, etc.), and date created. Store in the styrofoam box with the ice pack and place in your freezer (should be around -20 C). If you are taking it from yeast cake/slurry from a batch of beer you will have to know how to wash yeast.

Just a couple of extra notes and clarifications that have come from discussions post this email.

* The small starter (500ml-600ml) he makes first with the fresh vial. This gives a number of advantages in that you can generally fit the starter vessel and wort into a standard pressure cooker to sterilise.
* let the small starter fully ferment out to ensure the yeast have full glycogen stores and are in good health
* It is best to store the yeast in sanitised nutrient water than any beer. I originally asked him that storing at -20 degC may cause pepite mutants as it was not below-80 C (temps used by manufacturers). The answer is to store the yeasts with the nutrient rich water which doesn't provide any potential food as pepite mutants occur during cell multiplication.
* the nutrient rich water is essentially a cup of water with a pinch of yeast nutrient and sterilised.
* The yeast left from the smaller starter is then added to a standard starter for your main pitch.

Hope that helps. Good luck.

 

[WhiteWolf]

Bookmarked!

 

[Bribie G]

Sounds brilliant. One thing that strikes me, with slanting - you should keep the 'blank' slants for a week or so to see if any grow mould, so you chuck them and go with the good ones. With the tubes using the glycerine and freezing method, there is no "proving" period and I wonder if this introduces a small but significant risk?

 

[argon]

My method for creating a frozen yeast bank isn't too difficult. The beginning supplies you need are
-Styrofoam box that fits in your freezer
-Ice Pack
-Glass/Plastic Vials (look for 15-25mL glass vials OR use 50mL Flacon tubes)
-Turkey Baster (stainless steel if you can find it)(or spend the money and buy an electric pipette and 10-15mL pipettes. though that can get pricey)
-a rack to hold test tubes
-a pressure cooker
-glycerin
-something to label with
-sterilized yeast nutrient water
-latex/nitrile gloves
my basic procedure is as follows

Anyone know where i can get my hands on some glycerin?

 

[[email protected]]

Anyone know where i can get my hands on some glycerin?

Try a pharmacist or chemist. Glycerin also know as glycerol, glycerine.

 

[[email protected]]

Sounds brilliant. One thing that strikes me, with slanting - you should keep the 'blank' slants for a week or so to see if any grow mould, so you chuck them and go with the good ones. With the tubes using the glycerine and freezing method, there is no "proving" period and I wonder if this introduces a small but significant risk?

You are right about the no proving period before storage. The proving comes at the time of making the starter after storage. As you will step up the vial of banked yeast this will be your trial. Taste and smell the beer made from that sample to check OK as you would any starter and decide to continue or not.

For me as a homebrewer this technique suits me as I don't want to particularly get into yeast culturing in a major way. I don't want to keep samples for years or keep rare strains. I want to simply have some yeasts on hand and to get a little better economics from liquid yeasts at this stage with this hobby. I suppose you could look at as a stepping stone.

Who know's once you start you might not be able to stop and develop a full blown culture lab complete with stereo microscope and hemocytometer alongside your brewery!

 

[razz]

I've been into two chemist stores and no glycerine, the missus tells me today that it's in Woolies where the vitamins are.