Yeast from petri dish

[The Goatreich]

I've very kindly been donated some very special yeasts by a friend of mine that works in the business. However he's given them to me as cultures on agar in petri dishes and has shown me how to swab them into wort to get them to breed, but what I'm wondering is how long it would take from this small amount to build up to a 5 gallon pitchable amount if I put some into a starter?

Normally I know it's a few days before brewday to get a starter going, but this is a really small amount on the swab, so I'm guessing maybe another couple of days on top?

 

[graysalchemy]

I think you will need to make up a very small starter and work it up it will probably take a few weeks to get up to a gallon starter. Once you have that I think you will have to get a yeast bank going.

I have just started freezing my yeast. I put 25ml in a sterile test tube with 25 ml of a 50:50 water glycerine solution, this stops the cells rupturing so I believe. They are all numbered and i have made a spread sheet to keep track of them.

 

[DirtyCaner]

Impressive stuff Grays!

I have a big box of test tubes somewhere, no you;ve given me an idea what to do with them!

DC

 

[graysalchemy]

Have a lokk at this

andthis

 

[The Goatreich]

Well he did say that if I haven't made much use of the cultures after a few months then I can easily just create a fresh culture with another petri of fresh agar and swabbing from the original, so freezing isn't essential for keeping the original batches. So really I have an endless supply, as long as I keep the conditions right. I can see the benefit of freezing once I get a batch up to proper starter quantities though.

 

[DirtyCaner]

Good links, thanks Grays!

 

[lynchy]

Great links, i am thinking about getting jamils yeast book so i can start my own yeast bank. having listened to the jamil show on the brewing netwrok it seems like he knows his stuff and he talks about the yeast producing better beer when its 2nd or 3rd generation.

 

[Devonhomebrew]

Great links, i am thinking about getting jamils yeast book so i can start my own yeast bank. having listened to the jamil show on the brewing netwrok it seems like he knows his stuff and he talks about the yeast producing better beer when its 2nd or 3rd generation.

At work we use yeast feed and acid on the yeast so it forgets how youve treated it and it thinks its new when actually its the same culture from 1 year ago. Just skimmed off on day 3 and saved.

 

[lynchy]

Great links, i am thinking about getting jamils yeast book so i can start my own yeast bank. having listened to the jamil show on the brewing netwrok it seems like he knows his stuff and he talks about the yeast producing better beer when its 2nd or 3rd generation.

At work we use yeast feed and acid on the yeast so it forgets how youve treated it and it thinks its new when actually its the same culture from 1 year ago. Just skimmed off on day 3 and saved.

Are you sure i dont think thats how mutations and genetics work. The yeast should change over time due to the conditions its under.

 

[The Goatreich]

Anticipating a brew day in a couple of weeks I've just swabbed some of one of the ale yeasts into a 25ml starter and put it in the airing cupboard. I'll swoosh it around each time I think about it, and hopefully will see some growth over the next few days. I'll step that up to a 300ml starter then, and then onto a 1l.

 

[The Goatreich]

This yeast is now in a 300ml starter and seems to be growing well. I think I'll up it to a 1l starter tonight. I'm paying careful attention to the smell after my most recent disaster with my harvested US05 turning my brew into dog meat. :sick:

 

[The Goatreich]

Right, just made up 1 litre of wort with approx 100g of dry malt extract dissolved in and simmered for ten minutes, it's just cooling down in the sink now and I'll then add it to a demijohn and add the 300ml starter of the yeast that has been growing nicely over the past few days.

After the litre has grown for a few days will I need to up it again to a larger starter before hopefully pitching into 5 gallons of wort around 1.045-1.050 on Sunday?

 

[DirtyCaner]

I'm no sure but I made a starter up week n a half before i needed it, 500ml. Then Made it up to 1l 4 days before required. Seemed to froth up then die down. added it and Initial fermentation seems vigourous, 23l batch... so far so good ( all cultured with boiled mash water)

 

[The Goatreich]

Nice, thanks.

 

[DirtyCaner]

Checked it again today, still a nice big brown froth that's nearly out the FV. Smells like beer too!

In your last batch Goatreich, was there any clues the starter had gone bad? Did it smell like beer before you added it? Also, yu said it was a yeast cake you had kept, so was it the sludge out the bottom of your last brew?

Assuming my current brew is OK , I'm thinking of pouring another heavy style beer on top of this sludge after bottling....

DC

 

[graysalchemy]

One good test is to taste the fermented wort that the yeast grew in, if it tastes reasonable then it should be ok if it tastes off then fling it. sometimes i have made up a starter to early and forgoten about it or the yeast cake has been sat in the fridge to long and it has a meaty taste :sick: so I fling and get out a packet.

 

[DirtyCaner]

I see. Good, simple test, thanks.

How lond should you keep it in fridge?

My 2nd culture sat out for 2 weeks growing up to half a litre and is now in fridge...

 

[The Goatreich]

Checked it again today, still a nice big brown froth that's nearly out the FV. Smells like beer too!

In your last batch Goatreich, was there any clues the starter had gone bad? Did it smell like beer before you added it? Also, yu said it was a yeast cake you had kept, so was it the sludge out the bottom of your last brew?

Assuming my current brew is OK , I'm thinking of pouring another heavy style beer on top of this sludge after bottling....

DC

I think it may have smelled a bit meaty in the starter, but as it was my first one I didn't realise that it was actually a bad thing. When I tried cultivating from a bottle of Bengal Lancer I got smells of sour milk and thought it was all off, but after I left it a week and went to through it all out I found that the wort had turned into beer and smelled just fine.

It was from a yeast cake, but it was drained off the trub, and washed in boiled cooled water a couple of times.

yeast cake has been sat in the fridge to long and it has a meaty taste

You're the first person that has mentioned smelling this too! Thank god I'm not going mad. Mine was in the fridge for probably 6 weeks, maybe more.