Not just that each situation you put the yeast in will differ like Wolfy said, but each strain will behave differently as well.
Youve never made a starter and counted the yeast cells to compare the actual numbers to your calculated numbers, or the calculations from any other source?
As far as reproduction is concerned, all strains of yeast behave the same way, they reproduce via budding. This means that if the same number of viable cells from two different strains of yeast are placed in identical environments which are conducive to reproduction, they will both produce approximately the same number of daughter cells.
I'm curious Wolfy, why do you think yeast calculators like Mr. Malty are "virtually all guesswork with a large amount of error"
Do you have any kind of data to back up this claim?
Cool, then he won't mind providing it for us.
Youve never made a starter and counted the yeast cells to compare the actual numbers to your calculated numbers, or the calculations from any other source?
As far as reproduction is concerned, all strains of yeast behave the same way, they reproduce via budding. This means that if the same number of viable cells from two different strains of yeast are placed in identical environments which are conducive to reproduction, they will both produce approximately the same number of daughter cells.
sulli_42
Curious and curiouser, Wolfy has done a lot of work with yeast propagation, shared that work with everyone and established a solid reputation for knowing what he is talking about.
Who are you? You have been here for about six months all your posts bar 1 appear to be on yeast propagation.
Now personally I am a little dubious about some of the conclusions Mr Malty reaches, even more cautious about some of the assumptions people make when they try to apply the processes, but at least people are starting to recognise the importance of a big healthy pitch and take steps applying that to their brewing.
Do you have a background in the field, you are demanding that people prove assertions based on and linked to well documented research on the subject, had you gone back and read over the material you would have seen where those opinions were formed.
Under ideal conditions the reproductive pathway for yeast is well understood and researched and there are more than a few very good books on the subject. When it comes to applying that to home brewing there I would agree that there is a lot of guesswork and room for error, or to quote Wolfy
"Don't stress about too much numbers or calculations, they're virtually all guesswork with a large amount of error, focus on growing healthy yeast as your highest priority, then if you are anywhere even close to the 'right' numbers/volumes/counts, it will take care of the rest."
So back at you, you have a different opinion, what is it based on, or in your own words "Do you have any kind of data to back up this claim?"
Mark
I know of only one home brewer (and he's on the UK forums and not these ones) who actually counts yest cells, for the rest of us we are all dealing with 'educated guesswork'.
The most important thing to know about starter size is that the inoculation rate affects the rate of growth. In other words, the pitching rate'' of your starter has a big effect on the amount of new yeast cells you will see from any propagation. It is not the volume of the starter that is important, but how many cells you add in relation to that volume. Too high an inoculation rate, and you get very little growth. If you use too low an inoculation rate, then you are not really making a starter, you are fermenting beer.
Ideally, you want to grow your yeast in a large enough volume of wort to ensure optimal, yeast health and to get a decent amount of growth for your trouble.
Fire Away! ............. don't bother, I don't give a shit!
That makes you the 2nd home brewer (that I know of) who actually counts yeast cells, and that adds a deal of credibility to the calculations that you've provided. I'd suggest you post the yeast cell-count information on your website, including what methods you use and what the results were compared to the calculations for each starter you make, it adds both credibility and allows others to see - and hopefully understand - the margins of error involved. However from what I understand by reading the 'Yeast' book even cell count techniques have limitations and large error margins.Whoa...simmer down mate. I'm not trying to disrespect anyone, and I never said I had a differing opinion. In fact I agree with almost all of what Wolfy has to say. I just disagree with the rhetoric in some of his statements; namely that yeast growth calculations are "virtually all guesswork with large margins of error." White and Zainesheff et al. have done a significant amount of real science, i.e actual counting of yeast cells in various sized starters, in order to develop the algorithms that are used in their "calculations", and I could post up half a dozen mathematical formulas from various text books on yeast all based on hard science.
I myself perform cell counts on all my yeast starters every time I make a beer, and the numbers are consistently within 50 billion cells of what the calculations are. I would never claim that a mathematical formula can produce exact predictions of cell counts, they are most definitely ball park estimates
Was the following (or would have been if he'd not already started with his starter):I was going to start with a smaller wort volume but when I put the numbers into yeast calc it had my inoculation rate at over 260. I've read on here before that you need to keep it at between 50-100 so I increased the wort volume until I got below 100. If someone could explain which is correct that would be appreciated.
I don't think I said anything even close to that in this thread, and totally stand by my initial advice in this thread: get a refractomer and check the gravity and you will know - without any guesswork - if the yeast has fermented out your starter.but for someone to say in one breath that yeast calculators are all based on guesswork with huge margins of error and then offer up advice on what size starter to make or offer up a stepping regime based on his "calculations" seems rather contradictory. That's all.
As far as reproduction is concerned, all strains of yeast behave the same way, they reproduce via budding. This means that if the same number of viable cells from two different strains of yeast are placed in identical environments which are conducive to reproduction, they will both produce approximately the same number of daughter cells.
The most important thing 'we' need to know to answer that is how many viable yeast cells 'we' are starting with, so I'd be interested to know what Truman used for his estimate.Would people say based on whats been discussed above that the volume of the starter was excessive for the quantity of yeast being used to inoculate?
I then entered 25 billion cells into Yeast calc at 95% .... and I had it stored in the fridge for a month
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