Calculator for stepped starters

[Sulli]

YeastCalc

 

[SwampassJ]

YeastCalc

Very nice. Now I don't have to fiddle with Mr. Malty to figure out how to much starter is needed to turn 1 pack into 3 packs and in turn the 3 packs into a sizeable starter to 500 billion for a lager anymore.

 

[el_caro]

Nice one Sulli.

Wish it had an option for working with small samples (slants or various quantities of frozen yeast). Also working with quantities of washed yeast.

 

[Sulli]

Nice one Sulli.

Wish it had an option for working with small samples (slants or various quantities of frozen yeast). Also working with quantities of washed yeast.

if you know the approximate cell count of your sample, you can just enter it in manually. Then set the calendar date to any date in the future. The viability will then be 100%, and it will calculate the growth rate from whatever you have plugged into the initial cell count box.

 

[Revvy]

Looks cool

 

[diS]

Great work!
This is same as .xls version from before?

 

[Cromwell]

This is nice. However, it doesn't seem to take into account the amount of time the starter is allowed to grow, only the volume of the starter. Am I missing something?

 

[Sulli]

Great work!
This is same as .xls version from before?

Thanks diS, the .xls was the prototype, I thought it would be nice to have it accessible via the web, so anyone can use it.

 

[Sulli]

This is nice. However, it doesn't seem to take into account the amount of time the starter is allowed to grow, only the volume of the starter. Am I missing something?

normally, if your doing a stepped starter, you want the starter to ferment out completely before stepping up, this usually takes between 12 and 24 hrs, depending on temperature, oxygenation, viability, etc..
I also feel that it is best to chill and decant the spent wort before stepping, this avoids having to deal with upping the gravity of the next addition to compensate for dilution of the sugars from the fermented wort.

 

[StMarcos]

What am I doing wrong? I entered 16G of 1.062 ale. Starting with a tenth of a pack (10 billion cells)

0.1L stirplate, then
1L stirplate, then
8L O2....

All the other fields are reading 0......

 

[Sulli]

What am I doing wrong? I entered 16G of 1.062 ale. Starting with a tenth of a pack (10 billion cells)

0.1L stirplate, then
1L stirplate, then
8L O2....

All the other fields are reading 0......

Did you pick a date from the calendar?

 

[diS]

Date should solve it.
I see that new thing is Final Fermentation parameters. What do you think, can we use it for roughly estimating yeast count gained after harvesting (after taking flocculation into account)?

 

[StMarcos]

Yup, fixed it. Now I need to figure out how to make enough yeast for 16G of Dortmunder!

 

[orangehero]

What are the models for yeast growth that were used?

 

[Sulli]

Date should solve it.
I see that new thing is Final Fermentation parameters. What do you think, can we use it for roughly estimating yeast count gained after harvesting (after taking flocculation into account)?

Not quite sure I understand you. But with all the compounding variables involved with stepping starters, the final yeast cell count on the 'big cake' is really just a ballpark figure. In fact they are all just ballpark figures, just to get you inside of a given range.

 

[Sulli]

What are the models for yeast growth that were used?

All the data is based on Chris White's figures in "Yeast: The Practical Guide to Fermentation." If you have the book check out the numbers in fig. 5.5 page 140.

The growth rate was plotted from this data.

 

[Sulli]

I just finished putting together some charts showing how I got at the formula for the growth curves in my yeast calculator. For anyone interested in that sort of thing, they are here: Growth Charts
I'd love to hear your thoughts, questions, concerns.

 

[Phunhog]

This is fantastic!! Great Job!!

 

[diS]

I dont have to mention that it is already in my bookmarks.. but I am excel freak and I like it old way, so I am I still on 1st version.

Great help.

 

[ALF]

wow! really nice. this is exactly what I have been looking for.

 

[Sulli]

Thanks for the compliments guys, I appreciate it.

 

[kincade]

Nice job sulli. I met your buddy a few weeks ago and he gave me the link.

 

[Sulli]

After much research and several yeast starter experiments later, I have decided my aeration method multipliers were incorrect. Although, the final cells counts in my calculator correlated very well with Mr. Malty; this was only if no aeration method was chosen. I have spent the last week making starters with and without a stir plate, and have come to the conclusion that Jamilz is probably pretty close with his multipliers. As such I have adjusted the calculations in my calculator to be more in line with Mr. Malty, in fact for all intents and purposes they are nearly identical in their calculations. I am planning on purchasing a microscope and hemacytometer and continuing my experimentation, to get as accurate a yeast calculator as is possible. I realize that with all the variables involved with yeast, online calculators are fairly rough estimators of final yeast cell counts, but they are a good place to start, and they appeal to my inner beer geek. May all your beers be free from off-flavors.

 

[tom_hampton]

Sulli-


Jamil talks about a minimum inoculation rate on Brewstrong. But, no matter how dilute I make the starter in yeastcalc, I always get better growth than if I make it more concentrated...until I get below 0.1 mil/ml.

I haven't bought the book, yet...so, I don't know if he elaborates on this further there.

Is 0.1mil/ml the published limit?

 

[Sulli]

Chris White states that once the inoculation rate drops down to about 4 million cells/ml, the growth rate levels off and that, without additional efforts (i.e. aerobic fermentation); 100 billion cells are not going to grow into more than about 600 billion.
But when you're making a starter, you want the yeast to have an environment conducive to optimal health, and that occurs at higher inoculation rates, like between 50-100 million cells/ml, which is why if you need a large amount of yeast it's better to step it in smaller increments rather than try to get it all at once.

 

[tom_hampton]

Ok, thanks. So, your calculator stops at 0.1 b/ml or 100 mil/ml, thus the effects of low inoculation rate is not a factor in its results.

I was trying to play around with the effects of low viability, and wasn't sure where the limit was.

Now, if I can figure out how to get Beersmith to produce the same results...

 

[maffewl]

Very nice work!

 

[tom_hampton]

Ok, thanks. So, your calculator stops at 0.1 b/ml or 100 mil/ml, thus the effects of low inoculation rate is not a factor in its results.

I was trying to play around with the effects of low viability, and wasn't sure where the limit was.

Now, if I can figure out how to get Beersmith to produce the same results...

Ooops. Nevermind, I got my units wrong. Your calc goes down to 0.1 mil/ml, or 100,000 / ml.

However, even at that concentration it forecasts a very high growth rate of 50x with stir-plate (35x without). Is that accurate?

Anyway, I guess your/Chris' point is that smaller steps should be used to keep the concentration above 50 m/ml. Which is really the answer I was after.

Thanks.

 

[Sulli]

Ok, thanks. So, your calculator stops at 0.1 b/ml or 100 mil/ml, thus the effects of low inoculation rate is not a factor in its results.

I was trying to play around with the effects of low viability, and wasn't sure where the limit was.

Now, if I can figure out how to get Beersmith to produce the same results...

Actually, low inoculation rate is a factor in it's results. But there is a point of diminishing returns. If your inoculation rate is much lower than around 15 million cells/ml your not making a starter any more your brewing beer. In other words if your making a starter your inoculation rate should be chosen with the health of the yeast in mind (more does not necessarily mean better); and when your making beer your inoculation rate should be chosen with the health of the beer in mind. Two different animals and they each have different optimal inoculation rates.

 

[builderguy]

Okay...sorry if this is a silly question....

If I put 1.5L for Step 1, then 1.5 for step 2, does that mean I decanted and added another 1.5L of fresh starter wort, or that I poured an addition 1.5L on top of the original (so I would need a 3L flask in that case?