Tuesday, February 3, 2015
How time effects cell growth is a factor that I have felt is missing in the existing calculators, which led me to create this starer calculator. Another personal gripe I have with the commonly used calculators is their unrealistic implied accuracy. For honesty I have included one sigma error bars on the cell calculations. I've collected data from dozens of experiments and factored it all down into this Excel calculator.
This calculator also lets you select which strain of yeast you are using. Right now it is limited to US-05 and S-04, but I plan to expand this as resources allow.
You will need to enable macros to use this calculator.
This is the Beta Release, so give it a try and let me know what you think!
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Unable to get it properly to run in Libreoffice. Any change for a more open and free version of your calculator?ReplyDelete
Currently the starter calculator uses Excel, which limits the platform compatibility. There is a plan to make the calculator work on a wider variety of platforms, but there is no schedule in place.Delete
Thanks for getting back to me. I also tried it on MS excel on https://office.live.com/start/default.aspx but even here did it not work. I mean this is ms created by ms, should it not at least work here?Delete
That's too bad. Perhaps macros don't work on the web based version of Excel.Delete
Is your calculator only for stir plates?ReplyDelete
The calculator is for both stir plates and still starters. Click on the "Rate Wizard" button to switch from stir plate to still.Delete
Ah, thanks! When I compare Beersmith, Mr.Malty and your calculator it differs quite a lot. Mr.Malty says 1 pack in 1.6 L, Beersmith says 1 pack in 1.4-1.5 L and yours says 1 pack in 0.7 L. From what I've read in your article, 0.7 L will take me there without a stir plate - it just takes longer time, right? But why the big difference? Are the other calculators missing something?Delete
When I use them all side by side, I must say i somehow feel I trust yours the most though. :)
It seems to me that the other calculators are assuming an incomplete fermentation. More details here: http://www.woodlandbrew.com/2015/02/yeast-starters-stirred-vs-not.htmlDelete
Ok! So to make a long story short - as long as you complete the fermentation in the starter, and not end it prematurely with a cold crash, it's not needed to bump up the starter size if you don't have a stir plate? Am I understanding you're article correctly then?ReplyDelete
Steven, finally you gave the answer I was looking for! I've been reading a lot the last days about pitch rates and starters, and I just couldn't believe that making a good starter is really that complicated: stir plates, 2 or 3 steps, 2/3 times boiling wort, etc. I seem to understand that all that - if you're lucky - just helps you save perhaps one day of time... So, next time I'll definitely try to follow your approach.ReplyDelete
One question, though: how much do you feel will other yeast strains differ from the ones you already have in your sheet? Let's say other ale/weizen yeasts.
Within any one species the growth characteristics are fairly similar. The S-04 setting is good for most any ale, and S-23 is good for most lagers. In the next revision I'm planning to add Brett which is quite different from the Sacch species.Delete
Any news on this brett starter calculator? I've been looking for something that would model growth of a vial of WLP648 that I want to step up for a 100% brett fermentation.
Hi again! Thank you again for the calculator! As I've understand, a starter smaller than about 1 L may be harmful for the yeast. Also the optimum range for a starter should be 1.030-1.040. I got a batch that's borderline for using starter at all, but I want to be on the safe side.. I've used your calculator with good results before, but now it's suggesting a 0.7 L starter at about 1.010 SG. Or if I enter a larger container volume: 2.2 L starter of 1.002 SG. This can't be right, can it? Am I using it wrong?ReplyDelete
Can you tell me what you are entering into the calculator?Delete
Yes! Volume 10 L, Gravity 1,051, Stir plate, manuf. date 15-04-15, pitch date 15-05-21, rate wizard: us-05 (actual yeast WLP300), 20'c temp. According to the manufacturer, there should be enough yeast in one vial/smack pack for this batch. But all the calculators say's otherwise.. So it's quite hard to tell.Delete
Yes, I agree. For 10L (a half batch) of 1.051 wort you don't need a starter. Only about 100 billion cells are needed, and a one month old pouch should still have about that.Delete
That's what I did and I think it'll taste fine. But still, is it supposed to show those kind of numbers? If we're playing with the numbers of a little bigger batch (13L) and maybe a little bit older yeast? Then I probably gonna need a starter, and even then the numbers (about 0.7L starter at about 5.5 Plato) doesn't really seem to be right, does it..?Delete
A 0.7L 5.5°P starter sounds reasonable to me. The calculator tells you how to grow the cells you need. It it's a small number of cells it's going to give small numbers. The brewer needs to make the judgment call as to whether it's close enough without a starter. In my opinion if the cell count is within 20% the difference will probably go unnoticed.Delete
I'd like to see additional lines for step up's that use the output from the previous step. Possible ?ReplyDelete
Yes, that would be nice. It will take a while to implement, so no promises.Delete