Stir Plate And Whirlpooling

[wobbly]

Those that use a stir plate for starters does it make any difference if the "Whirlpool" reaches the bottom of the flask or not.

Seems to me that if it did you would induce more oxygen into the starter and help yeast growth.

Is this a good thing or not?

Should you stop introducing oxygen after some time (6, 12, 24 hours?) on the stir plate?

Cheers

Wobbly

 

[argon]

Makes no difference really. As long as the yeast is kept in suspension it's fine. The motion of the stirring is exposing the ever changing surface to air/oxygen anyway so the fluid is definitely getting enough aeration.

Anytime i use my stir plate, i only pitch the decanted yeast slurry after chilling etc. If i want to pitch an active starter (the whole volume in active fermentation) i don't use a stir plate as i don't want the fermenting wort to be aerated/oxidised.

Edit: I know some people that use the stirplate for about 12hrs before turning it off and allowing the starter to go. But don't do this myself as i feel the risk of adding (potentially) oxidised beer to my main wort can introduce unwanted flavours

 

[Crusty]

Those that use a stir plate for starters does it make any difference if the "Whirlpool" reaches the bottom of the flask or not.

Seems to me that if it did you would induce more oxygen into the starter and help yeast growth.

Is this a good thing or not?

Should you stop introducing oxygen after some time (6, 12, 24 hours?) on the stir plate?

Cheers

Wobbly

For a 25l batch I use a 2L starter.
I add 200g DME to the flask, top up to the 2l mark, dissolve & boil for 15mins to steralise.
I then put the flask in the sink, cover with foil, & add ice & get temp to 18-20deg & add my pre-smaked liquid yeast.
I stir for a full 24hrs & put flask into fridge to drop yeast overnight. The next morning, I take from fridge, allow to come to room temp, decant all but the slurry & pitch. My beers have become even better since doing starters, especially with attenuation & seem to gain 1 or 2 gravity points.

 

[sama]

Over at the brewing network theres a great podcast on starters,if ya get a chance have a listen.theres a good little read at mrmalty.com under the yeast starters heading also that will answer your questions.

 

[Yob]

Quick question.. new to all this stirplate malarky but I love it..

I was given some yeast a month or so ago, so last week I took half of it and put it on the stirplate and grew up a nice pitchable amount.. dropped it and collected the yeast and have stored it until yesterday when I took it out of the fridge.

So I felt that Id like to wake them up to pitch this arvo so have put it back on the stirplate this morning to get em going.

Was gunna leave it on the plate for a few hours, turn it off and then pitch this arvo if when I get a bit of activity..

snip from Mr malty

"There is no need to make a starter a week in advance, because I pitch the whole starter, liquid and all (up to a certain size of starter). Yes, you can wait longer and completely ferment it out so you don't have to pitch the liquid, but if you're going to do that, you should use a larger starter and allow the fermentation to go complete cycle over several days, chill, decant the beer and pitch just the yeast. If you're making a smaller starter, it is better to just pitch the entire active starter within about 6 to 12 hours of pitching the yeast into the starter."

so thats the plan 3 hours on the plate, 3 hours to get going, pitch to Wort.

sound reasonable?

 

[marksfish]

did you make up a fresh starter, if yes your good to go if not you may deplete the yeasts energy stores.

 

[Yob]

Yeah was a fresh starter, I took it off the plate and threw it in the fridge with the cube to get the temps within range and went out for lunch/shopping.. have come home to find it developing a nice little krausen.. by the time I faff about for an hour and sanitise the FV and rack the cube I rekon she'll be good to go.

Cheers

 

[Thirsty Boy]

Dont worry about "hours" - you can see. If the starter has a shit ton of bubbles rising through it and foam on top, its fermenting its little rectum off and is at full activity. Leave it on the stir plate until its doing that, then pitch it. That'll take in my experience, more than six hours, but it'll depend on how fresh your yeast is.... if you have a smack pack that swelled up in an hour or two, sure its realistic, otherwise not so much.

Remember, Jamil is using yeast that whitelabs or wyeast probably made the day before yesterday...... you have stuff that got shipped over here probably more than a month ago, if you're lucky. It makes a difference. your eyes are the best tools you have to tell you what sort of a difference its making for the starter in front of you now.

 

[Yob]

thanks TB.. I more often than not use visuals/perception as the rule to go by with most process.. The orig. starter was jumping out of the flask so was confident with vitality.. the starter today was as active as I could hope for.. After an hour or so in the fridge next to the cube a decent krausen was forming..



within an hour of pitching I had this



Will be giving it another whisk before beddie bo bo's

:icon_cheers:

 

[dr K]

Marginaly OT but it is important to remember that a starter is is a starter and a starter is all about making yeast, you certainly should see some activity (unless your yeast is dead!) but the sugars in the starter will be quickly consumed.
When you add your starter to a much higher volume of wort, the you are making beer..party on yeasties...
K

 

[Yob]

I can grasp that the growth is/should be done by then and that its all about the beer but is it not worth giving them a bit of a whisk after a few hours?

 

[Thirsty Boy]

no no - growth wont be done by then... maybe its a bit past the point where its useful to give it more oxygen once its got karusen going, I'd probably not bother.

mind you, I've never gotten, nor am i sure I'd want that much activity so soon.... that'd kind of freak me out. There's supposed to be some sort of lag phase, and I dont know where your's has gone. I genuinely have no idea whether hitting krausen that fast is a good or bad thing, but its not bloody normal thats for sure, or at least not in my experience.

healthy ******* yeast I guess.

 

[Thirsty Boy]

Marginaly OT but it is important to remember that a starter is is a starter and a starter is all about making yeast, you certainly should see some activity (unless your yeast is dead!) but the sugars in the starter will be quickly consumed.
When you add your starter to a much higher volume of wort, the you are making beer..party on yeasties...
K

Not all that quickly, and not really sgnificantly more quickly than they would in any normal fermentation - the yeast aren't super respirators (ok, no respiration is actually happening, I know that) just because its a starter, and it will take a while before they ferment the sugars out completely. As it normally would.

Sure it will probably be faster than in your fermenter because you presumably have the temperature higher, pitch rates higher and oxygen levels higher.... but why would a yeast that normally might take several days to eat up all the available sugar, suddenly be able to eat it all in a few hours? It cant and doesn't - and if it did, it didn't do any growing on the way. You shouldn't see "some" activity, you should see plenty, if your yeast is growing, its fermenting and all the usual signal apply.

 

[Yob]

Cheers for that.. For clarification, some/most of that foam pictured was from the drop from the cube/whisk however, flecks can be seen about the edges so there was some action happening... This morning its a mass of 'true' krausen.

Once again, cheers

 

[Yob]

healthy yeast I guess.

I'll say.. it's dropped over 30 points in 2 days... Krausen almost blew out the top and has already collapsed back

:beerbang:

 

[Yob]

Hay all, back for more of this stirplate info..

as TB noted above when the starter (on the stirplate) starts bubbling its arse off and is a high activity like



thus.. is it time to turn it off and let ferment out or keep it spinning?

I dont want to pitch oxidised wort into this IPA that it's planned for as it's the brew I want to enter Vicbrew with.

Advice?

Cheers

 

[Steve@PMF82]

Hay all, back for more of this stirplate info..

as TB noted above when the starter (on the stirplate) starts bubbling its arse off and is a high activity like

View attachment 57144

thus.. is it time to turn it off and let ferment out or keep it spinning?

I dont want to pitch oxidised wort into this IPA that it's planned for as it's the brew I want to enter Vicbrew with.

Advice?

Cheers

Looks pretty active to me mate, in which case if you intend to pitch the whole lot (*active starter) you want to pitch it now.

Otherwise as you said let it ferment out, yeast drop, decant spent wort and just pitch yeast.

 

[Charst]

Hay all, back for more of this stirplate info..

as TB noted above when the starter (on the stirplate) starts bubbling its arse off and is a high activity like

View attachment 57144

thus.. is it time to turn it off and let ferment out or keep it spinning?

I dont want to pitch oxidised wort into this IPA that it's planned for as it's the brew I want to enter Vicbrew with.

Advice?

Cheers

personally I let it spin until I can no longer see bubbles rising out of the wort, leave it spinning overnight after that, then chuck it in the fridge. next day i decent the wort and pitch the yeast, having said that if your dumped 2 litres at high krausen into a dirty big hoppy AIPA i doubt youd really pic the oxidation.


EDIT: Beaten while writing

 

[Wolfy]

I dont want to pitch oxidised wort into this IPA that it's planned for as it's the brew I want to enter Vicbrew with.

Then don't!
Let it ferment out, settle, decant the spent starter-beer and pitch only the yeast into your comp-entry-beer.

 

[Yob]

was certainly leaning toward letting it finish and decanting.. They have had about 24hrs on the plate to this point.

When is it right to stop the plate and let them ferment out? Will they still build their glycogen and trehlose reserves if they are still getting the o2 from the plate?

I might have to have a flick through the yeast book again this week

Cheers