Renewing The Yeast Cultures

[Zwickel]

yeah, youre right, if you are using top fermenting yeasts, you dont need that much.

The most of my beers are Lager or Pilsener beers. As you know, when using bottom fermenting yeasts, you need much more of it than using top fermenting yeast. Also Im doing 60l batches, so I have to use about 1% of the batch size stiff yeast, thats about 600ml stiff yeast.

For top fermenting beers like Ales, youd need less than the half of it, say 0.3% of the batch size.

Cheers

 

[Zwickel]

Just to complete the procedure of yeast farming.

how to inoculate:

Im taking one of that little thingy:

sterilized over hot steam, to lengthen it, you my use a skewer as well, dip it into the yeast slurry and then just roll it over the agar.

Dont fill yeast into the slant! just touch the agar with a contaminated cotton-wool swap.

At first you shouldnt see any yeast on the surface of the agar. After a couple of days you will notice some thickness on the surface, later it will turne grey.


Thats all.

Cheers :icon_cheers:

 

[BenH]

Thank you Zwickel. You've demystified the process - I'm going to give it a go now!

 

[Sprungmonkey]

Zwickel - just wondering how much agar agar to water to DME you use for making the slants? Also do you add other nutrients?

 

[ausdb]

After another day you may see now a huge foam head in the vessel, now you transfer the content into a larger vessel, Im taking 5l bottles, add the rest of the wort, stirr well and start airaiting it and start cooling down slowly. For cooling I put the whole equipment into my fermentation fridge.

here another pic:

Then after another day add some more wort to it, depends on how much yeast youll need.
Meanwhile the temp has reached about 10to 12C.

Zwickel can you please post a picture of the stir bar that you are using in the 5l bottle, I know the bottom of the bottle is convex and I was wondering how well the stir bar stays centered or do you have problems with it flying off?

 

[Zwickel]

Zwickel - just wondering how much agar agar to water to DME you use for making the slants? Also do you add other nutrients?

howdy homebrewers,

I dont use any DME although it would be right using it.

Im producing about 70 to 75 liters of wort every brew Im doing, but cant ferment more than 60litres of it.

The overplus Im gonna freeze in one liter portions. So whenever I need fresh wort for starters, Im taking one part of it
and no, I do not add any other nutrition.

Im using around 5g of agar for 1 litre of wort. The agar you may get at any Asian Food Shop, costs really peanuts.
Before youre going to add the agar to the wort, it would be better if youre dissolving the agar powder in cold water, it avoids clumping.

Fortunately I own a freezer/fridge combination exclusively for my brewing stuff. The freezer is used to store hops and wort and the fridge for fermenting.

@ausdb, no worries, the stir bar centers immediately when you put it into the bottle. It works very well.

Later at the afternoon I will post you some pics of it, right now Im sitting at my workplace, remember, were about 8 hours behind you.

Cheers :icon_cheers:

 

[AndrewQLD]

Later at the afternoon I will post you some pics of it, right now Im sitting at my workplace, remember, were about 8 hours behind you.

That sucks Zwickel, I bet you wish you lived here in Australia, that way you would be Knocking off work right about now and tucking into a beer.

Never mind, I'll have a Weizen for you now :lol:

Cheers
Andrew

 

[Zwickel]

That sucks Zwickel, I bet you wish you lived here in Australia, that way you would be Knocking off work right about now and tucking into a beer.

Mate, you dont know how true that is

Never mind, I'll have a Weizen for you now :lol:

I hope, next holiday of mine we can have beer together next eachother.

Cheers :icon_cheers:

 

[ausdb]

@ausdb, no worries, the stir bar centers immediately when you put it into the bottle. It works very well.

Later at the afternoon I will post you some pics of it, right now Im sitting at my workplace, remember, were about 8 hours behind you.

Thanks very much, I have 2l and 3l erlenmeyer flasks and have trouble keeping the stir bar centred even though they are flat bottomed when there is a large yeast load. I was thinking of using a 5l bottle like yours but thought I would have trouble keeping the bar centred because of the domed base.

 

[Zwickel]

Thanks very much, I have 2l and 3l erlenmeyer flasks and have trouble keeping the stir bar centred even though they are flat bottomed when there is a large yeast load. I was thinking of using a 5l bottle like yours but thought I would have trouble keeping the bar centred because of the domed base.

yeah, Ive used Erlenmeyer flasks too, but in my Opinion, the bottles are much more handy.

Your trouble keeping the stir bar centered could be even because of the flat bottom.
Maybe the stir bar spins much easier if the bottom is domed, due to the friction, just a thought.

Anyway, I will post some pics Ive already taken.

Cheers :icon_cheers:

 

[ausdb]

yeah, Ive used Erlenmeyer flasks too, but in my Opinion, the bottles are much more handy.

Your trouble keeping the stir bar centered could be even because of the flat bottom.
Maybe the stir bar spins much easier if the bottom is domed, due to the friction, just a thought.

I will try it as I went to buy a new stir bar with the ring around it yesterday but the lab supply place had sold out. One thing that I do like about erlenmeyer flasks is being able to put them on the stove and boil the starter wort and stir bar in the same flask that I will be culturing my yeast in as I use DME for my starters. It means I can cool it in the sink then pitch the yeast in and not worry about sanitising more containers or unnecessary transfers, but a 5l demijohn like you use costs only $17 whilst a 5l erlenmeyer costs over $50.

 

[Zwickel]

I will try it as I went to buy a new stir bar with the ring around it yesterday but the lab supply place had sold out. One thing that I do like about erlenmeyer flasks is being able to put them on the stove and boil the starter wort and stir bar in the same flask that I will be culturing my yeast in as I use DME for my starters. It means I can cool it in the sink then pitch the yeast in and not worry about sanitising more containers or unnecessary transfers, but a 5l demijohn like you use costs only $17 whilst a 5l erlenmeyer costs over $50.

Thats fine mate, of course an Erlenmeyer flask looks more professional than a bottle of "Hobos Heaven"
but for myself I found the bottles more handy.

oooops....A$17 for that bottle? We pay 4.98 Euro for 5l of red or white wine in that bottles, just the half of it

thats my collection of stir bars, the upper one (on top of the pic) is the one Im using most:

here you can see a test run with water and airation.
I dont use that plastic diffusor anymore, Im now using a sintered brass diffusor as you can see in the pic above:

and here something you may lough at:

that looks quite funny, but its nice to see how much CO2 is produced as the balloon gets big and bigger.

Cheers :icon_chickcheers:

 

[kabooby]

From the info in this thread I have recently started to store my yeast on Agar.

I used to just store the yeast in stubbies but this was starting to take up to much fridge space.

I have made up 24 slants and just innoculated 2 with some Burton ale yeast WLP023, so well see how they go.

What is the main purpose of the Agar? Couldn't you just make up a malt mixture and store it just the same? The obvious difference is that the Agar makes the malt solution solid, but what is the advantage of this?

Kabooby

 

[matti]

Agar is food for cell!?

correct me if I am wrong.

 

[Franko]

Kabooby
what did you use for your slants - tube wise


Franko

 

[Sammus]

Here's another useful link in culturing - maybe a little more tech and finicky, requiring that everything is sterilized properly (ie autoclaved/pressure cooked).

Also, I noticed Zwickel said to dissolve the Agar in cold water. Maybe disperse it through? One of the properties of that Agar stuff is that it won't dissolve until the liquid is nearly boiling.

Also, boiling stir bars is a bad idea - they loose their magnetism when heated up. I lay out some glad wrap, spray with some iodophor and keep it wrapped up, then just drop it in when I need it. The glad wrap is good because you can handle the stir bar through the film without touching it directly.

 

[Zwickel]

Also, I noticed Zwickel said to dissolve the Agar in cold water. Maybe disperse it through? One of the properties of that Agar stuff is that it won't dissolve until the liquid is nearly boiling.

have you ever done it? you can see the difference very well. Put it in hot wort and youll get clumps, hard to dissolve. No problem in cold wort.

Also, boiling stir bars is a bad idea - they loose their magnetism when heated up. I lay out some glad wrap, spray with some iodophor and keep it wrapped up, then just drop it in when I need it. The glad wrap is good because you can handle the stir bar through the film without touching it directly.

the stir bars are made to get autoclaved. Otherwise you could use a stirbar only once.
After use Im sterilizing the bars in a steam pressure cooker.
We have stir bars in our laboratory they get used since more than 10 years and steady autoclaved, they havent lost theire magnetism, not at all.

anyway, its not a good idea to stir the hot wort with a magnetic stirrer, thats simply unnecessary, just boiling is enough.

Cheers :icon_cheers:

 

[kabooby]

Agar is food for cell!?

correct me if I am wrong.

I thought the malt was the food for the yeast, could be wrong though.

Kabooby
what did you use for your slants - tube wise


Franko

Hi Frank,

I am using the LP9025 UL containers from here

Got 100 of them :blink:


I will try dissolving the Agar in cold water next time. It did clump in the hot water.

So is the Agar food for the yeast as well as the malt?

Kabooby :icon_cheers:

 

[Zwickel]

the food for the yeast is in the wort, mainly the sugar thats in.
Agar is nothing for the yeast, is basically colourless, odorless and flavorless, just makes the wort stiff.

The trick is, the yeast spreads over the surface of the agar, dissipating all the nutrients it can get and falls asleep.
In a solution, the yeast would be affected by the alcohol and autolysis, not so on the surface of an agar bottom.

One day when you fill in a little bit wort into the slant, only the yeast cells alive will start to regenerate and get into the wort.
All other crap like dead yeast cells will remain in the agar. So after you have transferred the initial wort to a bigger vessel, you have only living cells extracted (theoretically)

Cheers :icon_cheers:

 

[mfdes]

Hi Zwickel,

I notice in your post that you had the wort on a stirrer and ALSO were adding aeration. Have you found the added aeration to make a significant difference?
I get very good growth just on the stirrer, but was wondering whether adding extra air is worth the contamination potential.

MFS.