Decant a yeast starter from a stirplate

[PSNCO]

After 25 years of brewing and making yeast starters the way it was done 20+ years ago, I got a stir plate and I am AMAZED at what it does to get a starter going. I've built up to 1500mL of pitching small amounts of 1.040 OG wort into the starter. Can I take it off the stir plate, let it settle and then decant off most of the fermented liquid, throw it into the fridge? Then 24hrs before I brew, add more wort at 1.040 and put it on the stir plate to kickstart and dilute the "slurry"?

BTW, this is an ale yeast.

 

[BWE]

After 25 years of brewing and making yeast starters the way it was done 20+ years ago, I got a stir plate and I am AMAZED at what it does to get a starter going. I've built up to 1500mL of pitching small amounts of 1.040 OG wort into the starter. Can I take it off the stir plate, let it settle and then decant off most of the fermented liquid, throw it into the fridge? Then 24hrs before I brew, add more wort at 1.040 and put it on the stir plate to kickstart and dilute the "slurry"?

BTW, this is an ale yeast.

You ABSOLUTELY can!! I personally would chill it before I decant though, just to be sure all of the yeast has fallen. Then let it come up to room temp, and add more Wort.

 

[bajaedition]

For a lager I will double start the yeast, It pays off
and yes stir plates are the shiznit

 

[day_trippr]

Definitely cold-crash before decanting, otherwise you may be selecting for high flocculation which may in turn cause lower attenuation...

Cheers!

 

[mikitz]

Interesting topic... the affect that cold crashing has on yeast is an interesting one. Through successive generations and starters, your yeast population (along with cell properties) can change and mutate, this is normal.. a highly flocculating yeast might have a small child population of lower flocculaters. You have the ability to either keep these new lower flocc'ing ones by cold crashing, or getting rid of them by decanting after only a short cold crash..

So I am not sure that cold crashing a starter for a day or two before decanting is always the way to go. Especially if you want to conserve the flocc'ing properties of your original yeast population. But I have no idea how to do this any kind of precision.

 

[radwizard]

I always cold crash my starters if I'm going to decant. I only decant if I am building, end up delaying my brew day, or have a bigger starter (a lot of fermented liqud). For simple lower OG beers that don't require a big starter, I usually just pitch the whole thing straight of the plate.
I didn't use a stir plate for a long time as well. Looking back, it should have been one of my first investments in brewing.

 

[day_trippr]

[...]So I am not sure that cold crashing a starter for a day or two before decanting is always the way to go. Especially if you want to conserve the flocc'ing properties of your original yeast population. [...]

Unless you're ok with pitching an entire starter (I'm not - especially when the nth growth cycle is in a 5 liter e-flask) spent beer and all, a thorough cold-crash is about the only option to grab as much of the total yeast population as possible...

Cheers!

 

[kh54s10]

IMO, if you don't cold crash a starter, or at least let it fully ferment then sit for a while (which is not the best practice) you will be pouring out a lot of yeast. You need to cold crash to get the yeast to drop out of suspension.

 

[day_trippr]

Coincidentally I was getting another growth cycle ready for some Conan and some 1318 for a double batch brew day Sunday plus some for storage so I took a pic of the cold-crashed flasks.



Light was low = a lot of camera noise so it's hard to tell how well the yeast dropped but it's pretty much all on the bottom.

Just got the next cycle on the stirrers...



Cheers!