Harvesting yeast from a starter

[spook123_uk]

Hi guys,

I'm going to brew a California common beer today and have made up a 2L starter with WLP California Lager yeast which is going great on my newly built stir plate all night. I put in 2L of water to 200g DME and got around 1040.

I realistically think I only need 1.5L of starter in all reality. Given this and I want to try my hand a harvesting yeast, is it feasible for me to pitch 1.5L and keep back 500ml to harvest the yeast from??

My thinking is it'll be nice and clean, free from and hop gunk etc.

Thanks,
Rich

 

[MyQul]

Yes. It's known as overbuilding your starter. You'd probably need to add another 2L of starter to the yeast harvested from the 500ml. Brulosophy says you can go to at least 13 generations doing this

http://brulosophy.com/methods/yeast-harvesting/

 

[spook123_uk]

Excellent. Thank you.. It's whizzing round on the stir plate at the moment. I think I'll pour off 500ml into a jar and whack it in the fridge ready for next time and pitch the remaining 1.5L

Next time round, once it's chilled, I assume I pour the beer off the top, add the yeast left to another starter and go again?

 

[BeerCat]

Excellent. Thank you.. It's whizzing round on the stir plate at the moment. I think I'll pour off 500ml into a jar and whack it in the fridge ready for next time and pitch the remaining 1.5L

Next time round, once it's chilled, I assume I pour the beer off the top, add the yeast left to another starter and go again?

That's what i have been doing and it's working fine.

 

[ManseMasher]

There are some that say if you aren't going to use it for a while it is more healthy for the yeast to pour off the liquid from the top, then add boiled, cooled water. Personally I haven't done that, and my next brew will hopefully be with one I've had in the fridge for 6 months. I have some dried yeast on standby though....

 

[spook123_uk]

Thanks all. I took 500ml off and poured direct into a sanitised swing top bottle as I don't have any jars yet.

It's in the fridge and I'll transfer to a jar (and maybe replace the beer with boiled and cooled water) when I get one.

 

[spook123_uk]

I've just been reading another post about storing year and the wort / beer being carbonated.

I now have more questions.. This morning, there was a solid 1/2 inch at the bottom of the bottle in the fridge. I thought I'd open the cap a little and sure enough, it fizzed and vented co2. The beer it's stored in is now quite heavily carbonated and the yeast is back in suspension (mostly floating on the top as krausen I think).
How do I now get this into a position where I can realistically use it again?

Should I keep venting until it's no longer fizzy then let it settle back and replace the beer with cooled boiled water?

It's a bit smelly too but then again, I think it's quite a concentrated yeasty beer smell.

On the plus side, the remaining 1.5L that int into my new brew is going great guns. It showed signs of bubbling after 3 hours and by this morning, it was really bubbling away.

Cheers,
Rich

 

[MyQul]

The C02 has no way to vent just like when you open a bottle of beer. Take the cap off completely and cover the bottle with some foil. If you use star san spray the foil. If you don't have any don't worry, when it comes to brewing sanitising is my religion.

 

[spook123_uk]

Thanks MyQul.

I'll get the foil and stars out! Much the same way i made my starter. Should I be leaving it in the fridge still?

 

[MyQul]

Thanks MyQul.

I'll get the foil and stars out! Much the same way i made my starter. Should I be leaving it in the fridge still?

Yes, keep it in the fridge then take it out to warm to room temp before you want to use it.

 

[spook123_uk]

ok. So I now have this in my fridge with yeast sediment at the bottom.

I also now have some 500ml kilner jars. How should I go about replacing the beer with boiled, cooled water? how much should go in to it?

Also, how to I try to make any assumptions about how much yeast is there?

Thanks,
Rich

 

[mike77]

I leave mine stored under beer rather than water. Numerous sources I've read suggest yeast stores better under beer as the ph, alcohol and hops provide antibacterial protection. Also washing the yeast provides an unnecessary opportunity to introduce infection. That said if the beer is high alcohol percentage then it may not be ideal.

When I use the yeast I pour off the old beer and create a fresh starter.

 

[mike77]

Also if you decide not to was the yeast then I would just leave it where it is for now. Use the jars to collect more slurry from your fermenting Californian common and store that in the fridge to build more starters from. That way you'll have a ton of yeast

 

[spook123_uk]

I may well just leave it under beer then. As I harvested from a starter, it was a 1040 sg mix of water and dme before the starter was made.

How do I guess how much I have?

 

[MyQul]

I may well just leave it under beer then. As I harvested from a starter, it was a 1040 sg mix of water and dme before the starter was made.

How do I guess how much I have?

Get an identical glass bottle and fill it up with water to the exact same level as the yeast then measure how much water you have (I use my wilko trial jar as it has 1ml graduations on it after 10ml. Your will have about 1.5billion cells per ml in there. I have read variations on the amount from 1.2bl/L to about 2bl/L so I've decided to got for 1.5 to stay on the conservative side. Especially as Wyeast say 1.2bl/L

"Generally 40-60% yeast solids will correlate to 1.2 billion cells per ml"
https://www.wyeastlab.com/com-yeast-harvest.cfm

You need about 200bl cells for 23L <1.060 iirc

 

[spook123_uk]

ok. So I've done the test and there seems to be around 10ml. By my reckoning, that's around 15 billion cells.
Given that for example a white labs pack is around 100 billion cells, should I now be doing something with this to build it up with another starter before storing it to use with a starter?

I have the ability to make 2L starters but am wondering if this will be enough if I only start with 15 Billion?

I'm thinking, should I make a 1L starter from it and store the lot (minus a lot of the finished beer on top which I could decant off)?

Or am I going down the wrong path?!

 

[MyQul]

ok. So I've done the test and there seems to be around 10ml. By my reckoning, that's around 15 billion cells.
Given that for example a white labs pack is around 100 billion cells, should I now be doing something with this to build it up with another starter before storing it to use with a starter?

I have the ability to make 2L starters but am wondering if this will be enough if I only start with 15 Billion?

I'm thinking, should I make a 1L starter from it and store the lot (minus a lot of the finished beer on top which I could decant off)?


Or am I going down the wrong path?!

Yes, your right. You'll need to step it up. Decant the spent wort off and put it into 1L starter. Ferment it out,crash it in the fridge and pour the spent wort off again. Then put it into 2L of wort. That should give you about 218 billion yeast cells. I used this yeast calc to work that out, based on a brew of 1.047 and a brew lenght of 6 USG (23L)

http://www.brewunited.com/yeast_calculator.php

 

[spook123_uk]

I'm getting there with this! I stepped it up in a 1L starter and after crashing it, I now have around 18ml of yeast. By my reckoning, that'll be around 25 - 27 billion cells.

Next up, I'll put it all into a 2L starter and see what that gives me.

On a side note. I collected the slurry from the bottom of the FV when it had finished into a jar which has given me around 350 - 400ml of solids at the bottom of the jar with a little beer on top after chilling for a few days. There was no dry hopping so it should be fairly clean apart from the Isinglass I put in at the end.

How does that equate with these calculations for yeast count?

 

[MyQul]

Putting your 18ml (which I calcualted to be 27billion cells at 1.5b/ml using a stir plate) into a calc. You should end up with about 309 billion cells. Plenty for a beer of less than 1.060

The slurry you collected will have all kinds of **** in it - you'd really have to rinse to measure it

 

[spook123_uk]

I may have a go at rinsing but for now, I'll concentrate on building my clean yeast back up so will build a 2L starter from the 18 or so ml I currently have then see what that yields.

Would it be better to do that now or wait until a few days before I want to use it again?