How Long on Stir Plate

[private4587]

About to use a liquid yeast to make a starter, my question is how long do i leave it on the stir plate before i harvest some and use the rest in my brew.

 

[Dutto]

I normally take:

• 24 hours to make a starter from a packet of dry yeast.
• 24 hours to make a starter from yeast recovered from the trub.
• 72 hours to make a starter from yeast recovered from a bottle.

Here are three photographs of a yeast I took from a bottle of Muntons Pedigree Amber Ale (It said "conditioned in the bottle" on the label.)

It still has another 24 hours to go before I would consider using it ...

START

AFTER 24 HOURS

AFTER 48 HOURS

By tomorrow I should be able to use it for a small (10 litre) brew but I will keep it going until Thursday because my mate's grandson wants to know how I make beer and I plan to let him brew a couple of DJ's worth.

I'm sure other Forum Members will have other ideas ...

... especially as I have never used a bought liquid yeast!

Take the time to look at this video. It's well worth the time it takes!



BTW - if you think that the lad in the video is a bit OCD about sanitising things - he isn't!

 

[strange-steve]

Unless you're starting with a very low cell count, 18-24 hours is enough to reach maximum cell density.

 

[RichardM]

I usually make my starter on a Friday evening for pitching to a 21 litre batch on Sunday afternoon

 

[foxbat]

I usually give it 48 hours on the stir plate after activity has started. Longer than strictly required but it doesn't do any harm.

If it's a flocculent yeast you'll know when it's done because you'll see clumps whirling around as it tries to flocculate. Otherwise the best indicator is the colour change to a milky coffee light brown.

This is my calendar assuming I'm brewing on the following Sunday:

Tuesday evening: use calculator to build starter. Enter 100 into the overbuild box so I've got 100bn cells saved over for my next brew. Assuming that gives me 1.5 litres vs 1 litre with zero overbuild. Put starter on stir plate in brewfridge at 20C.

Keep peeking curiously at it every few hours...

Thursday evening: Stir plate off. Temperature control off. Use a few neodymium disc magnets to lift the stir bar out of the yeast and leave it stuck to the inside of the flask. Decant 500ml into large sterilised Kilner jar. Brew fridge on to crash the starter. Kilner jar tightened, then loosened back 1/8 and left to crash with starter.

Sunday evening after brewday: decant 90% of spent wort off crashed starter catching some in a glass. Taste glass. It should taste of nothing much. Hope it doesn't taste off. Swirl remainder around and pitch when it's all loose. Fully tighten Kilner jar, move to back of kitchen fridge and hope wife doesn't notice. That's my 100bn cells and "manufacturing date" for next time. Expect to see full throttle activity in fermenter on Monday evening.

 

[private4587]

thanks for your quick replies, my yeast should turn up today so will use calculator once i have date from yeast, will be going for an overbuild so to use for my next brew.

 

[private4587]

So after receiving my liquid yeast and putting details into calculator i need to make a two step starter to get my amount of yeast required plus an overbuild. Do i make the 1st stage and place on stirplate for 24/30 hours and then chill to separate yeast from wort, pour off excess wort make up 2nd stage build and place on stipulate for another 24/30 hours and then take off overbuild and use the resultant yeast in my brew.
Thanks for any advice

 

[foxbat]

Yes. Decanting the first stage spent wort off is how you make room in your flask to pour in the second stage DME.

Are you making a lager or a big beer by any chance?

 

[private4587]

a larger, Sam Adams boston lager and the Brooklyn lager

 

[foxbat]

a larger, Sam Adams boston lager and the Brooklyn lager

That explains the big starter!