Calculator for stepped starters
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SwampassJ
Well-Known Member
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.
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Sulli
Well-Known Member
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.
Looks cool
Cromwell
Well-Known Member
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?
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Sulli
Well-Known Member
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Sulli
Well-Known Member
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
Well-Known Member
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......
0.1L stirplate, then
1L stirplate, then
8L O2....
All the other fields are reading 0......
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Sulli
Well-Known Member
Did you pick a date from the calendar?
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)?
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
Well-Known Member
Yup, fixed it. Now I need to figure out how to make enough yeast for 16G of Dortmunder!
orangehero
Well-Known Member
What are the models for yeast growth that were used?
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Sulli
Well-Known Member
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Sulli
Well-Known Member
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.
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Sulli
Well-Known Member
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.
I'd love to hear your thoughts, questions, concerns.
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Sulli
Well-Known Member
Thanks for the compliments guys, I appreciate it.
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Sulli
Well-Known Member
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
Well-Known Member
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?
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?
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Sulli
Well-Known Member
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.
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
Well-Known Member
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...
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
Well-Known Member
Very nice work!
tom_hampton
Well-Known Member
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.
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Sulli
Well-Known Member
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
Well-Known Member
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?
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?
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Sulli
Well-Known Member
You can add the second step to the first if you want, but then you have to adjust the gravity of the second step to compensate for the dilution of the sugars from the spent wort of the first step, and as you've already realized, if you decant you can build up a lot of yeast with just a 2000ml flask.
To answer your question though, the number you enter into the starter volume field is the amount of new wort your adding to the previous step. The cell counts in yeastcalc shouldn't change much regardless of whether you decant or not.
MonkeyWrench
Well-Known Member
Great calculator, but I have a question.
What numbers do I use for this situation:
1st step: 1000ml/100g starter
2nd step: add another 1000ml/100g starter to it
3rd step: decant off the 2000ml of liquid, then add another 2000ml/200g starter to the yeast
What numbers do I use for this situation:
1st step: 1000ml/100g starter
2nd step: add another 1000ml/100g starter to it
3rd step: decant off the 2000ml of liquid, then add another 2000ml/200g starter to the yeast
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Sulli
Well-Known Member
The volume you enter in to each step is the amount of new wort added to the starter, whether you decant or not.
So for your example you would enter:
1 liter in the first step,
1 liter in the second step,
2 liter in the third step.
MonkeyWrench
Well-Known Member
Ya, I tried that, but the second step shows 0 growth because the inoculation rate turned red. Now I see why, I had over 200 as a result.
Really, my problem is I have a 2 year old packet of dry I'm playing with, I really don't even know where to put my initial number since according to the chart, I don't have any viable yeast. After all 3 of the above steps, I have a solid 3/4" of yeast in the bottom of a gallon jug. I suppose I should transfer into my e-flask and figure out how many ml of yeast I have. Supposedly there are 4.5 billion in a ml of yeast solids, and about 25% that number when in a slurry, so I'll just go with 1 billion per ml and I should be safe. I'll probably divide it all into half-pint canning jars with 100ml in each and do a 1000ml starter for each brew.
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Sulli
Well-Known Member
Sorry, I didn't realize you were working with dry yeast. The viability calculations in YeastCalc are built around the properties of liquid yeast, not dry yeast.
That said, everything I've read about dry yeast, leads me to believe you shouldn't make a starter with dry yeast, you should just rehydrate it in water and pitch. From White and Zainasheff's "Yeast" pg. 133: "Many experts suggest that placing dry yeast in a starter just depletes the cells reserves that the yeast manufacturer tries to build into their products. For dry yeast do a proper rehydration in tap water; do not make a starter."
I think I read somewhere that dry yeast loses about 2% viability per month, so assuming 100% viability 2 years ago, you should be around 48% viable cells. Assuming your using an 11.5 gram packet of yeast, which contains approximately 20 billion cells/ gram, you should have about 119 billion cells left in your packet of yeast.
MonkeyWrench
Well-Known Member
Ya, that's what I figured. And yes, you really shouldn't make a starter with dry, but when working with something so old, I really just wanted to make sure it was good. Since I figured it was about half viable, it only gave me as many cells as liquid would, so not enough to hydrate and pitch, hence the starter.
Had I found your calculator earlier, I would have done things a bit different, I may have stressed the yeast on the second step assuming 119b cells, then a 1000ml starter on a stir plate gave me 251b cells. Then adding another 1000ml 1.040 starter actually gave me 2000ml of 1.025. I just hadn't realized that or I would have made it 1.070 to make up for the lack of fermentables in the full wort. Entering 1 liter for volume of step 2 and starting that step with 251b cells gives an error because the inoculation was too high.
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