Best way to split a starter?

[TheJasonT]

I have plans to brew two batches of a Strong Scotch Ale on Monday (7/1). I made a 1.6L starter of Wyeast 1728 last night (6/27). The starter is currently on my stir plate and happy as a clam. I would like to split this into two starters. What would be the easiest way to split this?

What I'm thinking is to split the well-mixed starter between two sanitized mason jars and let them chill out in the fridge for a night. Then tomorrow evening (6/29), I'll decant one, make a starter for it, ferment for 24 hours, then decant it and pitch it on brewday. The other will get its starter made on brewday and pitched the next morning.

Are there any issues with this plan?

 

[Hex23]

The main issue I see is not having enough time for two decants. Even with 1728 as a highly flocculent yeast, it may not flocc well enough in time and you'll pour out the least flocculent (higher attenuating) cells. You didn't say how you plan to decant on the second round, but I assume with some cooling. Supposedly with a chill then decant method, you're really supposed to make sure the yeast complete fermentation so they can build up their reserves before going dormant - that might be more like 72 hours.

Edit: When you turn off the stirbar, how fast does the yeast settle? And how big is the starter going to need to be for the second round? If it's not more than 5%, especially on a flavorful beer like that, you could skip decanting on the second round.

 

[Hex23]

Are you going to make the second batch on the same day - like brew 11 gallons and split the wort? If not, another approach would be to brew one batch ferment it with your whole starter, then harvest yeast from it for the next one that you brew a couple weeks later. You could just pitch on top of the first cake, or harvest a slurry. The latter would give a more accurate pitching rate.

 

[TheJasonT]

It will be two slightly different 5.5 gallon batches. I'm kinda crazy like that.

I'm thinking, based on ya'lls advice, that it will be easier if I just grab another pack of 1728 and make a second starter Sunday night prior to brewing and use it for the second batch.

Thanks all.

 

[Hex23]

It will be two slightly different 5.5 gallon batches. I'm kinda crazy like that.

I'm thinking, based on ya'lls advice, that it will be easier if I just grab another pack of 1728 and make a second starter Sunday night prior to brewing and use it for the second batch.

Thanks all.

Even easier and only an extra $6

 

[bd2xu]

I'm about to do this too, plan on decanting, then stirring up the slurry well and pouring into a sanitized measuring cup. Measure how much I have (maybe a half cup), stir well again and put 1/4 cup into one carboy and 1/4 cup in the other.

 

[Hex23]

I'm about to do this too, plan on decanting, then stirring up the slurry well and pouring into a sanitized measuring cup. Measure how much I have (maybe a half cup), stir well again and put 1/4 cup into one carboy and 1/4 cup in the other.

One thing I don't particularly like about more complicated starter scenarios is that it get's more difficult to estimate how much yeast you have. In the OP's case, he definitely would have needed a second round of starter wort, otherwise he would have been under pitching. In your case, I hope your original starter is big enough to handle the two batches, because it doesn't sound like you intend to step it up.