Stir Plate help - yeast calculator

[zephed666]

Hello:

I am using the Brewer's Friend yeast calculator and had a question about the stir plate choices they have. What would be the difference from the Braukaier-Stirplae and the C. White Stir Plate under growth model and aeration? Are they not both stir plates? Sorry if this is a simple question but I am new to stirplates...

Thanks for nay help!

 

[laredo7mm]

Scroll down the page on Brewer's Friend starter calculator and it explains the difference in the "Yeast Growth Equations" section.

 

[kh54s10]

Those Stirplate, or agitation methods use different equations to determine the amount of cell growth. They don't refer to different stirplates. There is some debate on how much growth is achieved by the different authors. I would go with the one that gives more yeast. It is less of a concern to pitch too much yeast than too little. After you learn more you can choose the one you prefer.

Added: Or that ^^^

 

[zephed666]

thanks!
I do have another question about the starters. What is the second and third step? Is that making another starter from the original?

 

[kh54s10]

thanks!
I do have another question about the starters. What is the second and third step? Is that making another starter from the original?

Yes, This usually comes into play when the size of a starter needed for the recipe exceeds the size of the equipment available.

For instance a lager might require a 4 liter starter. If you only have a 2 liter flask you do steps until you have the yeast of a 4 liter starter.

You usually make the first step a little weaker in gravity, let it ferment 18-24 hours, chill and decant the liquid, then do the next step at normal starter gravity. About 1.038-1.040 The size can be adjusted on each step until you have the right cell count after all the steps.

 

[zipster222]

I think the Brewkaiser stirplate is the one where air from an aquarium pump is forced into the vortex of the stirplate culture. Brew Kaiser tried cultures with and without air, and he found higher yields with.

http://braukaiser.com/blog/blog/2013/03/19/access-to-air-and-its-effect-on-yeast-growth-in-starters/

 

[zephed666]

Thanks!

So if I am using this right, I am making a high gravity ale - 1.067 OG. (5.5 gallon wort volume)
Using the target pitch rate of Pro Brewer 1.0.
The yeast I just got is from 10/12/16. Wyeast 1764

So I'm getting a target pitch rate of 336 Billion cells.
Am I reading this correctly?

 

[zipster222]

I use the pitch calculator:

http://www.yeastcalculator.com/

For a 5.25 gal 1.067 gravity batch of ale, it recommends 243 billion living cells. Since your cells are pretty old (10/12/16), this calculator asks for 675 billion old cells (i.e., dead plus living). You can use the calculator to determine how much starter wort you need to get to the desired number of viable cells.

 

[zephed666]

I use the pitch calculator:

http://www.yeastcalculator.com/

For a 5.25 gal 1.067 gravity batch of ale, it recommends 243 billion living cells. Since your cells are pretty old (10/12/16), this calculator asks for 675 billion old cells (i.e., dead plus living). You can use the calculator to determine how much starter wort you need to get to the desired number of viable cells.

Thanks. So according to that calculator for a 5.5 batch I would need 251 Billion cells. So I can do a two step starter each being 1.5 Liters and ending with a total of 264 Billion cells. Does that sound correct?

 

[zipster222]

It depends on how many cells that you are starting with. A standard white lab tube has 100 billion cells. According to yeastcalculator.com, you wold have 36 billion viable cells. 2X 1.5 liter starter with a simple stirplate (Zainesheff) would give you 350 billion cells. With a Braukaiser stirplate (K Troester) you would get 433 billion.

According to yeastcalculator.com, you would need 255 billion cells.

 

[zephed666]

I am starting with the Wyeast pack from 10/12/16. I don't have a stir plate, just using the shaking every time I walk by method...

what is the best calculator to use? All 3 show differing rates for starters to get the proper amount of viable cells - Brewer's Friend, Brewunited and Yeastcalc...

 

[zipster222]

I suspect that Wyeast is similar to White labs. In that case, according to yeastcalculator.com, you would get 264 billion cells with intermittent shaking.

I have only used yeastcalculator.com Not sure which calculator is best.

 

[zephed666]

I suspect that Wyeast is similar to White labs. In that case, according to yeastcalculator.com, you would get 264 billion cells with intermittent shaking.

that is what I was getting with the 1.5 liter starter. But on Brewer's friend it ends up with 190 Billion...

 

[zipster222]

I think that these recommended pitch rates are just ball park estimates. If you average the two numbers, you get 227 billion which is just 16% less than 264 billion (i.e., within experimental error). In general over-pitching is less of a problem than under-pitching.

 

[thunderwagn]

I've used all the referenced yeast calculators and have made great beer using each one. I drove myself crazy trying to figure out the best and going back and forth with different numbers for each. I finally ended up just going with one of them and sticking with it. I chose Brewers Friend, and I only chose that one because that's the brewing software I use.
I'd just pick one and go with it. Pick one that you feel most comfortable with and fits your style best and I'm sure you'll be just fine.

 

[zipster222]

I agree with Chuckwagen completely.

 

[zephed666]

thanks for all the help! I'm still green with yeast starters. Done about 5 of them and never a 2 or 3 step one.
But now is the time to try!

 

[drunkinThailand]

just a note - pick the one that says less yeast, then adjust so your starter has enough according to that one (if you're not sure/worried about underpitching). if you pick the one that says more yeast you are risking underpitching which seems like some posters had backwards.

other than that, just pay attention and learn as you go. everyone's system is different, so you may need to adjust up or down based on myriad factors. the first time is kind of a shot in the dark, but after that you will have an idea how it worked out, and adjust from there.

 

[sky4meplease]

+1 for choosing the model that predicts the least growth. My experience, which includes cell counts, says the growth models are way to optimistic.
Additionally, if your not using a stir plate give your starter plenty of time.
I have run split starters side by side (one on and one off the stir plate) and the non stir plate starter took 24+ hours longer to complete.
If you have a set up that you use to inject pure oxygen into wort when brewing beer you can do the same to your starter a few times during propagation as an alternative to a stir plate. I do this when I make starters too large for my stir plate.