1 Stir plate; 2 Starters - how often to switch?

[winvarin]

I am doing two, 1.2L starters to split between a 10 gallon batch I am brewing this weekend. I put each starter in a 2L flask. But I only have 1 stir plate (I do have a stir bar for each though).

Both starters were pitched with yeast 13 hrs ago. One went to the stir plate. This morning, both starters have about 1/2 inch of krausen.

My initial plan was going to be to give one yeast 24 hrs on the stir plate, then switch them and give the other 24 hrs. That would be Friday night. Then I could let them drop out before brewing Saturday.

With this much activity this soon, I am thinking it makes more sense to switch now and give them 12 (or so) hour shifts on the stir plate.

Thoughts?

 

[BansheeRider]

I am doing two, 1.2L starters to split between a 10 gallon batch I am brewing this weekend. I put each starter in a 2L flask. But I only have 1 stir plate (I do have a stir bar for each though).

Both starters were pitched with yeast 13 hrs ago. One went to the stir plate. This morning, both starters have about 1/2 inch of krausen.

My initial plan was going to be to give one yeast 24 hrs on the stir plate, then switch them and give the other 24 hrs. That would be Friday night. Then I could let them drop out before brewing Saturday.

With this much activity this soon, I am thinking it makes more sense to switch now and give them 12 (or so) hour shifts on the stir plate.

Thoughts?

24 hours each then cold crash would be fine. Have fun

 

[winvarin]

I decided to go with the 12 hour rotation. I figure as quickly as it took off and wen to full krausen, it's good to give each of them some time on the stir plate in the early growth phase. Since it's a holiday, I'll be around to swap them as needed

 

[BansheeRider]

I decided to go with the 12 hour rotation. I figure as quickly as it took off and wen to full krausen, it's good to give each of them some time on the stir plate in the early growth phase. Since it's a holiday, I'll be around to swap them as needed

I don't think it matters unless you are pitching at full krausen, in which case you would not put the starters in the fridge. If this is not your plan then why not give them 24 hours each on the stir plate? You would only be growing more yeast and you can cold crash, decant, then pitch at room temp. If you are brewing this weekend I would put one starter on the plate today and put in the fridge tomorrow. Then make the other starter tomorrow and put in the fridge Saturday morning. Then you can brew Saturday night giving your second starter at least 12 hours in the fridge for the yeast to drop.

 

[winvarin]

I just figured it was a matter of growth rate. Yeastcalc says I should get about 20-25 billion more cells with a stir plate vs intermittent shaking.

My assumption is that at 24 hrs, the bulk of yeast growth would be done in both flasks. My thought was that if flask 2 went on the stir plate after 24 hrs of "intermittent shaking" growth, then I wouldn't see much benefit from the plate. I am thinking that by putting them each on the plate for 12 hrs in the first 24, the pitching rates will be closer on Saturday. Is my logic flawed?

 

[BansheeRider]

I just figured it was a matter of growth rate. Yeastcalc says I should get about 20-25 billion more cells with a stir plate vs intermittent shaking.

My assumption is that at 24 hrs, the bulk of yeast growth would be done in both flasks. My thought was that if flask 2 went on the stir plate after 24 hrs of "intermittent shaking" growth, then I wouldn't see much benefit from the plate. I am thinking that by putting them each on the plate for 12 hrs in the first 24, the pitching rates will be closer on Saturday. Is my logic flawed?

No not flawed at all, either way you will have beer. I just figured you would have more yeast if both flasks had the full 24 hours on the stir plate. And since you are not brewing until Saturday you have plenty of time. It's up to you, either way you will make beer.

 

[winvarin]

They'll both wind up with 24 hrs on the stir plate. It's just that instead of giving them 24 and 24 respectively, I would give them 12 on, 12 off, 12 on, 12 off.

 

[winvarin]

No not flawed at all, either way you will have beer. I just figured you would have more yeast if both flasks had the full 24 hours on the stir plate. And since you are not brewing until Saturday you have plenty of time. It's up to you, either way you will make beer.

It's all math at this point. Even with the "intermittent shake" method, yeast calc only had me 2 billion cells below optimum pitch rate.

When you figure margin for error, I am likely good either way. Especially since both of these tube are less than 2 months old an took off quickly.