Basics Of Making And Using A Yeast Starter

[Wolfy]

Thanks for the replies guys, its good to know it will be useful, I was not sure how many people are already doing this stuff and how many are still learning about it all.

ahem... yeast sub-forum... ahem h34r:

That's been said a few times before, but I'm not sure the powers-that-be like the idea so we'll just continue like this.

made a quick climate control box for my yeast as its a bit cool in my lab area(has a laugh to himself)Used a 55lt esky temp control for heating and an old brew pad.Sat on a nice cosy
20 oC and both flasks are ready to go through the settling period before being used on Friday and Saturday.

That's a really good idea, I just keep my starter in the lounge room where it we usually have the aircond or heater on to keep it about low/mid 20s.

One question though: If pitching the entire active starter in as I usually do, the first point about conditions not being needed to make good beer (temp aeration etc) is less so as far as I understand. I believe if you pitch 2 litres of oxidised estery beer into your wort, those flavours can transfer to the final product.

I treat my starters with vigorous shaking until krausen appears, then leave it alone at roughly ferment temps.

manticle when I was suggesting that the starter and beer wort should be the same, I was not thinking so much about the flavours in the beer, but what happens to the yeast in that situation.

From what I understand the yeast 'adapt' to the particular wort they are in, they condition themselves to operate best in those conditions, hence, if you take the yeast when it is most active and pitch it into identical wort, they continue as they are and everything is good. However if you pitch the yeast into different wort (say you brew AG but made a starter from LDME for example) the yeast get 'shocked' by the new conditions and have to spend time and energy changing and adapting to the new situation, this is not good for them or your ferment (think of the extreme example of growing bugs in fresh-water and then throwing them directly into sea-water, you'd not expect them to adapt to easily).

On the other hand, by letting the yeast fully ferment out the starter and then settle, they can build up their sterol/glycogen reserves (almost like a dormancy phase), hence when you pitch them into the 'different' wort they wake up, use up those stored-reserves which help them to adapt to the 'new' conditions, and away they go. Yeast pitched when it is most active does not have those reserves built-up so they have a more difficult time adapting.

While I understand the logic behind leaving the starter ferment out - without shaking - after you see yeast activity, the 'Yeast' book and the Wyeast link above, both detail that the constant stirring or shaking is not just about oxygenation, its also about mixing the yeast into the starter and de-gassing CO2 all of which help grow more healthy yeast. So while not shaking the fermenting starter would reduce oxygen induced off-flavours, it may also result in less healthy and happy yeast than could have been made with more constant agitation. Pitching the entire starter is much easier and can be done more quickly, so in those situations using your approach would be a logical compromise.

Have been toying with this idea for a while, but have been worried about the ph of the last runnings and its effects on the yeast; what are your thoughts?

I did not think it would have a significant effect, but that may have just me being lazy rather than testing it, maybe its something you should do.

Great thread, however the iamge of your flask on a stove with alfoil brings bad memories. Did the same thing the other week and ended up with 120 degree water all over the ceiling and floor. Nasty burn to! Needs a warning!

Good point, I don't sit the foil tightly on the lids and always make sure the gas and wort can escape if it needs to - something which it does all too often and then I spend 1/2 hour cleaning up the stove top from burnt-sticky-starter-wort.

 

[manticle]

manticle when I was suggesting that the starter and beer wort should be the same, I was not thinking so much about the flavours in the beer, but what happens to the yeast in that situation.

From what I understand the yeast 'adapt' to the particular wort they are in, they condition themselves to operate best in those conditions, hence, if you take the yeast when it is most active and pitch it into identical wort, they continue as they are and everything is good. However if you pitch the yeast into different wort (say you brew AG but made a starter from LDME for example) the yeast get 'shocked' by the new conditions and have to spend time and energy changing and adapting to the new situation, this is not good for them or your ferment (think of the extreme example of growing bugs in fresh-water and then throwing them directly into sea-water, you'd not expect them to adapt to easily).

On the other hand, by letting the yeast fully ferment out the starter and then settle, they can build up their sterol/glycogen reserves (almost like a dormancy phase), hence when you pitch them into the 'different' wort they wake up, use up those stored-reserves which help them to adapt to the 'new' conditions, and away they go. Yeast pitched when it is most active does not have those reserves built-up so they have a more difficult time adapting.

While I understand the logic behind leaving the starter ferment out - without shaking - after you see yeast activity, the 'Yeast' book and the Wyeast link above, both detail that the constant stirring or shaking is not just about oxygenation, its also about mixing the yeast into the starter and de-gassing CO2 all of which help grow more healthy yeast. So while not shaking the fermenting starter would reduce oxygen induced off-flavours, it may also result in less healthy and happy yeast than could have been made with more constant agitation. Pitching the entire starter is much easier and can be done more quickly, so in those situations using your approach would be a logical compromise.

I oxygenate frequently until krausen appears to help with growth but don't let it ferment out. I pitch active starters. I think it's worth pointing out that IF you intend to pitch the whole starter, that you should treat it more gently once visible signs of fermentation appear orrisk adding oxidised, estery beer to the main product (wherever the starter wort comes from).

I always use the same wort and understand that concept completely.

Hopefully that's clear. Apart from that distinction (and it's the distinction between active starters and stepping up which can be combined as you suggest), I think the guide is really well explained and illustrated. Very useful stuff.

 

[haysie]

I pitch active starters.

Do you reckon it makes a difference Mants? I pitch healthy 2-5 day old chilled yeast, it always goes off like a rocket within hours.

edit, I remember Screwy having a few problems years ago with disapointing beers. Starters and the opinion/consensus at the time was the oxgenated content of the active starter.

 

[manticle]

I think the healthy bit is the key.

Bear in mind this is my take, not brewing science so I could be wrong but active starters to me are as healthy as top cropped yeast. If your chilled stuff is healthy and fresh then there's probably not much difference. If stepping up from older yeast or recultured yeast as I often do then I need to make the yeast happy and healthy.

I have noticed a difference between making active starters and ptching a smack pack directly when fresh.

It's not a crazy difference though so I only do it if I'm growing the yeast numbers first. A050 wort gets a smack pack straight in. By 'always' I mean when I make and use a starter, I always pitch it when active.

 

[manticle]

A050 wort gets a smack pack straight in. By 'always' I mean when I make and use a starter, I always pitch it when active.

And by 'A50' I mean 'a 1050'. Too late to edit.

 

[Logman]

Thanks for these great yeast posts Wolfy, noobs paradise! Just getting into liquid yeast and have been reading the various posts on the subject re stir plates etc.

A potentially stupid question but beginners gotta run the risk of that or die wonderin' Regarding preparing the wort when it's necessary to step up the starter size - do you prepare both flasks on the same day and put a rubber stopper (or foil top) on the larger starter and then just pitch the smaller one in at high krausen, or does the second wort need to be boiled and sterilized etc when you are about to transfer?

I would be doing it in my fermenting fridge with tempmate so the flasks would both be sitting in there.

 

[adz1179]

so im going to have a go at making a starter next weekend out of reclaimed 3068 yeast for a dunkel im planning. After reading a few threads i reckon i have the hang of it, let me know if you see any problems with the proposed method.

after racking my last hefeweizen, i left the slurry behind in the fermenter, added a liter or so of distilled water, stirred it up and collected two jars 1/3 full each. topped up with distilled water and shook a few times, now have 2 of these:



will replace the water a few more times until its cleaner, pour off the top liquid and split into 125ml containers for future use.

1. brew the dunkel as per normal and collect the last 1-2lts of wort trub and get this to 1.035 - 1.040. boil this for 15 mins.
2. No chill the dunkel for 24hours, at the same time, pitch 125ml of the yeast i have stored into the saved (boiled) wort and shake every few hours
3. put this in the fermenting fridge at 19deg (planned brew temp).
4. After 24 hours (give or take), add the wort to the fermenter, drain the starter (or pitch it all in?) and away we go.

sound about right?

 

[Wolfy]

after racking my last hefeweizen, i left the slurry behind in the fermenter, added a liter or so of distilled water, stirred it up and collected two jars 1/3 full each.
...
sound about right?

There is nothing 'wrong' with what you suggested, however, one of the main benefits of harvesting yeast from a previous batch is that you should have more than enough yeast cells to pitch directly into your next beer - which means a starter is not necessary. In theory your 125ml yeast slurry should have at least 300 billion yeast cells, if that is not enough to direct-pitch use the other jar of yeast you collected.

 

[elollerenshaw]

Have read this thread and others on yeast starters with interest.

What would be a typical pitch rate for an extract ale brew? (million cells/ml)
Does it really matter?
My basic understanding is that more yeast is better than less. Can you put too much yeast in?

 

[adz1179]

There is nothing 'wrong' with what you suggested, however, one of the main benefits of harvesting yeast from a previous batch is that you should have more than enough yeast cells to pitch directly into your next beer - which means a starter is not necessary. In theory your 125ml yeast slurry should have at least 300 billion yeast cells, if that is not enough to direct-pitch use the other jar of yeast you collected.

Thanks Wolfy. Will it last in its current form till next weekend? Just keep changing the water, get out 125ml and pitch straight in?

With the leftovers that I store, and plan to use in a month or 2's time, will they need a starter?

 

[davo4772]

Have read this thread and others on yeast starters with interest.

What would be a typical pitch rate for an extract ale brew? (million cells/ml)
Does it really matter?
My basic understanding is that more yeast is better than less. Can you put too much yeast in?

Extract, all grain. Doesn't matter where the wort comes from the pitching rate is the same. According to Mr Malty you need 220 billion cells. The number of cells will change according to the original gravity of the wort. Higher gravity means more yeast cells required. Also temperature of fermentation affects the number of cells required. Generally the lower the fermentation temperature, more yeast cells required.

Pitching rates matter. My understanding is you need some yeast growth to get desirable flavours into your beer. Too much yeast and there is little growth which will affect flavour.

I suggest you listen to the Brew Strong podcasts Yeast Starters and Repitching yeast which will cover what you need to know.
Lots of pointless banter on these podcasts but thats what the fast forward button is for.

 

[Wolfy]

Thanks Wolfy. Will it last in its current form till next weekend? Just keep changing the water, get out 125ml and pitch straight in?

With the leftovers that I store, and plan to use in a month or 2's time, will they need a starter?

Stored slurry should be fine for 1 week, and up to 2 at a stretch - after that it will be much less viable.
Once it's been washed clean, just store it like it is, each time you wash it/change the water/etc you increase the chance of introducing infections/bugs/etc.

After a month or two you'll need to make a starter, because a large portion of the yeast will have died.

 

[lukasfab]

ok so from what I have read in the last few post is that reclaimed yeast should be all good to pitch direct into the next brew?

pic shows what i have from last weekend

 

[Wolfy]

ok so from what I have read in the last few post is that reclaimed yeast should be all good to pitch direct into the next brew?

pic shows what i have from last weekend

Yes, but don't leave it stored for too long before repitching.

 

[lukasfab]

cheers Wolfy

do you taste test the wort on top or the yeast just to make sure its all good
and obviously you pour out the wort and pitch just the yeast?

cheers

 

[Wolfy]

do you taste test the wort on top or the yeast just to make sure its all good
and obviously you pour out the wort and pitch just the yeast?

With the concentration of yeast in the jar, I can't imagine the beer ontop would taste good.
If your previous beer was good, and sanitation and control processes adequate there is no reason to think the yeast has 'gone off' in the short time since you collected it.
But yes, I just decant the spent beer and pitch the yeast.

 

[Steve@PMF82]

cheers Wolfy

do you taste test the wort on top or the yeast just to make sure its all good Why not ? good way to get a better idea about yeast health is to taste everthing
and obviously you pour out the wort and pitch just the yeast? YES

cheers

 

[Karhunkynsi]

3 questions.

What is "Pitch"

What is "Krausen"

And how much of this liquid yeast would you use in a 23 litre fermenter.

 

[Phoney]

3 questions.

What is "Pitch"

What is "Krausen"

And how much of this liquid yeast would you use in a 23 litre fermenter.

Pitch is chunking the yeast into the fermenter. As in throw, cast, toss

Krausen is the fluffy brown goo that floats on top of your wort while it's fermenting.

Depends on quite a few factors. Beersmith has a yeast starter calculator and I believe there are a few others around on the web, but I generally make a 1L starter for a 23L ale.

 

[MaltyHops]

Yes, but don't leave it stored for too long before repitching.

Gday Wolfy,

With a jar containing a large amount of yeast like lukas' that has
been stored for a while - lets say 10% of the yeast might still be
viable - then chucking all the yeast in the jar into a starter/stirplate
would probably mean a quick ramp-up to creating a new starter?

How would the other 90% of dead yeast affect the starter or
resultant brew though? Just more nutrient for the other growing
yeast? Off flavours?

Cheers.