Yeast starters - oxygenating/oxidising??

[timcunnell]

Morning chaps.
Following last week's post on making a yeast starter I had a go this weekend and making up a starter with WLP002. The yeast came in a strange sachet thing, and came out surprisingly thick - not really liquid at all!? Anyway - hopefully it went okay.

My method was to take a clean 1.5l jar, which I sterilised by filling with boiling water. Then I added 70g of medium DME to 700ml of water and boiled that for a bit, then poured into my jar. I cooled the liquid to 20c then added the yeast and gave it a good old shake.

I proceeded to carry my "yeast baby" round the house with me for the next couple of days, giving it a right good shake as often as possible. By the end of yesterday it smelled pretty much of alcohol, and I pitched the whole lot into my newly brewed HBC ESB. This morning the brew was bubbling away merrily in my fridge, so I guess it has worked.

The only odd thing was that there were large, thick chunks of yeast at the bottom of the jar which didn't mix in with the wort when I swilled it round. Is this normal?

The only thing I was wondering to myself was when is it good/not good to try and introduce oxygen? I've learnt that it is definitely good to get oxygen into your wort before pitching your yeast. And its definitely bad to get oxygen into your beer before racking. So with a yeast starter is it ever bad to get oxygen in? (I hope not, as I've been doing so all weekend!!).

Cheers!

 

[McMullan]

Sounds like it went well, mate. All sounds normal. When you get confident, you could pour off the oxygenated starter wort and replace it with fresh beer wort giving it a thorough mix to resuspend (declump) the yeast and pitch. I never noticed any impact from oxygenated starter wort, but I do resuspend the starter cake in fresh wort. Seems to speed things up a little :thumb:

Edit: yes, O2 in the starter is recommended.

 

[timcunnell]

Sounds like it went well, mate. All sounds normal. When you get confident, you could pour off the oxygenated starter wort and replace it with fresh beer wort giving it a thorough mix to resuspend (declump) the yeast and pitch. I never noticed any impact from oxygenated starter wort, but I do resuspend the starter cake in fresh wort. Seems to speed things up a little :thumb:

Edit: yes, O2 in the starter is recommended.

Awesome - thanks very much for the reply!

I've got a home-made stir-plate ready to go for the next one so hopefully that'll help. Amazing what you can knock up with an old USB hard drive enclosure, a 12v fan and some magnets! :)

 

[clibit]

Well played Tim, you have a lovely yeast there and you prepared it well. Regular shaking, lots of oxygen, is a good thing for starters, I reckon.

 

[timcunnell]

Well played Tim, you have a lovely yeast there and you prepared it well. Regular shaking, lots of oxygen, is a good thing for starters, I reckon.

Great - thanks Clibit!!

I guess my next task, once I've fermented this beer and racked it off, will be saving this yeast to re-use again and again! More fun to come! :)

 

[clibit]

Great - thanks Clibit!!

I guess my next task, once I've fermented this beer and racked it off, will be saving this yeast to re-use again and again! More fun to come! :)

This is proper brewing. :thumb:

I suspect understanding yeast and handing it well is the core job of a brewer. A lot of microbrewers just chuck fresh dried yeast in each batch - so you have moved past that now!

Filling the jar with boiling water to sterilise it is probably not the best practice. I'm not an expert, but I believe brewers use chemicals to ensure sterility. You could boil the jar for a while, that would do it. But what you've done will be fine. Another method is to put them in the oven. 140C for 15-20 minutes.

I use Starsan for everything now. When i got it I wondered if it would live up to the hype - but it has, I've not, touch wood, had an infection since. I've read somewhere that Starsan provides some form of nutrient for the yeast, not sure if that's true.

https://www.reddit.com/r/Homebrewing/comments/2k55yk/star_san_as_yeast_nutrient_question_for_any/

 

[Covrich]

You need to shake it to resuspend the yeast anyway before pitching as it can stick to the bottom, or vigourously gyrate it to mix it in..

 

[McMullan]

+1 for starsan.

I've starting using a large pressure cooker too, to sterilise jars, starter wort, hop bags, etc.

 

[timcunnell]

Yeah I must say I converted to Starsan a while back after almost quitting brewing altogether. I was using VWP and literally everything I brewed was ending up down the sink. As soon as I started using Starsan I've had no problems at all.

To be honest I don't know why I didn't Starsan my yeast jar!!? I think I was mainly being lazy!!

So now I am interested in how to harvest the yeast at the end of this brew, and then how best to keep it and re-use it on the next one. More learning! :)

 

[clibit]

Yeah I must say I converted to Starsan a while back after almost quitting brewing altogether. I was using VWP and literally everything I brewed was ending up down the sink. As soon as I started using Starsan I've had no problems at all.

To be honest I don't know why I didn't Starsan my yeast jar!!? I think I was mainly being lazy!!

So now I am interested in how to harvest the yeast at the end of this brew, and then how best to keep it and re-use it on the next one. More learning! :)

Just put the yeast slurry in sterilised jars and use it to make a starter ahead of your brew.

 

[timcunnell]

Just put the yeast slurry in sterilised jars and use it to make a starter ahead of your brew.

Thanks Clibit. So am I right in thinking that I should store the yeast in a normal fridge? Then warm some up and make a starter as needed?

 

[clibit]

Thanks Clibit. So am I right in thinking that I should store the yeast in a normal fridge? Then warm some up and make a starter as needed?

Yes, that's it. :thumb:

 

[timcunnell]

Yes, that's it. :thumb:

Not sure if this is a daft question, but how would one know how much yeast to add to a starter? Assuming I stick to the 1/10 ratio and make 700ml water up with 70g DME. How much slurry would I add to that?

 

[clibit]

Not sure if this is a daft question, but how would one know how much yeast to add to a starter? Assuming I stick to the 1/10 ratio and make 700ml water up with 70g DME. How much slurry would I add to that?

It's a really good question, and I don't really know the answer. There doesn't seem to be an agreed way of using yeast slurry, I've read various methods from pitching slurry straight in, to waking it up with a bit of fresh wort, to making starters. But no clear guidance on how much yeast to make a starter. I would love to know myself how to be fairly confident about the number of yeast cells I am pitching. But making starters is a way to get closer to knowing. The amount of yeast is determined to a great extent by the volume and OG of the starter wort. You need to pitch enough yeast into the starter so that the yeast is not stressed - don't under pitch into the wort. This is why people who culture yeast from bottle conditioned beers step their starters up in stages,.

This shouldn't be necessary with slurry, you should be able to put enough yeast into a 1 or 2 litre starter to build it in one go. Don't worry too much, there is room for maneouvre, a tablespoon per litre would be my guess, but I'd be interested to hear other opinions.

If the slurry is very recent, you can pitch it straight in, and use mrmalty to estimate the amount.

http://www.mrmalty.com/calc/calc.html

You can also do a half way house, and add a bit of wort to your slurry on brewday to wake the yeast up at room temperature.

 

[timcunnell]

It's a really good question, and I don't really know the answer. There doesn't seem to be an agreed way of using yeast slurry, I've read various methods from pitching slurry straight in, to waking it up with a bit of fresh wort, to making starters. But no clear guidance on how much yeast to make a starter. I would love to know myself how to be fairly confident about the number of yeast cells I am pitching. But making starters is a way to get closer to knowing. The amount of yeast is determined to a great extent by the volume and OG of the starter wort. You need to pitch enough yeast into the starter so that the yeast is not stressed - don't under pitch into the wort. This is why people who culture yeast from bottle conditioned beers step their starters up in stages,.

This shouldn't be necessary with slurry, you should be able to put enough yeast into a 1 or 2 litre starter to build it in one go. Don't worry too much, there is room for maneouvre, a tablespoon per litre would be my guess, but I'd be interested to hear other opinions.

If the slurry is very recent, you can pitch it straight in, and use mrmalty to estimate the amount.

http://www.mrmalty.com/calc/calc.html

You can also do a half way house, and add a bit of wort to your slurry on brewday to wake the yeast up at room temperature.

Thanks Clibit! Another really helpful and informative post!! There are a few mysteries for me surrounding live yeast and everything involved with growing/keeping it.

As you said before though, it seems to be the key to professional brewing at the end of the day. I am really looking forward to discovering what a difference it makes to my end products!

 

[MyQul]

.

The only odd thing was that there were large, thick chunks of yeast at the bottom of the jar which didn't mix in with the wort when I swilled it round. Is this normal?

!

With this strain, yes it is normal. From what I've read about it, WLP002 is extremely flocctuant and clumps together as you've seen in your starter.

I'm guessing your looked a bit like this Youtube vid. You can see all the 'snot like' chucks flying around in the starter wort

[ame]https://www.youtube.com/watch?v=69W6ZoBLJHI[/ame]

 

[timcunnell]

I'm guessing your looked a bit like this Youtube vid. You can see all the 'snot like' chucks flying around in the starter wort

Thanks MyQul! Yes exactly like that really. Although also some much larger lumps. I do feel much better for knowing that it is normal anyway.

I have now made a home-made stir plate - so hopefully that'll help/prevent too much clumping next time.

If anyone is interested I could post a thread on how I've made the stir plate. I'm just not sure the components are stuff most people just have laying around. I am lucky that I run an IT department, and we have tons of old bits and pieces which can prove quite useful! :)

 

[MyQul]

Not sure if this is a daft question, but how would one know how much yeast to add to a starter? Assuming I stick to the 1/10 ratio and make 700ml water up with 70g DME. How much slurry would I add to that?

As clibit says a yeast calc is the way to go.

Harvested yeast is 1.2billion cells per ml

https://www.wyeastlab.com/com-yeast-harvest.cfm

So once you've worked out how much yeast you've harvested use a calculator to to work out how much to pitch/what size starter to make.

I like this calc as it tells you if you need to make a starter and how big

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

 

[MyQul]

Thanks MyQul! Yes exactly like that really. Although also some much larger lumps. I do feel much better for knowing that it is normal anyway.

I have now made a home-made stir plate - so hopefully that'll help/prevent too much clumping next time.

If anyone is interested I could post a thread on how I've made the stir plate. I'm just not sure the components are stuff most people just have laying around. I am lucky that I run an IT department, and we have tons of old bits and pieces which can prove quite useful! :)

You don't really need a stir plate (some people even argue it damages the yeast) the shaking method you used is sufficient, you just need to the starter a minimum of 4 times per day although now you've made one your going to want to use it - new toys :mrgreen:

Just a heads up: again from what I've read, this strain can be quite hard to rinse out of trub because it's so flocctuant it drops to the bottom of your rinsing vessel before te trub does.

 

[McMullan]

You don't really need a stir plate (some people even argue it damages the yeast)

:nah: Others have shown with data that yeast growth is significantly higher in stirred starters compared to shaken starters. I am not aware of any data supporting the opinion that stir plates damage yeast cells. :-D