Author Topic: Dunkelweizen fermentation  (Read 3347 times)

Offline Werks21

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Re: Dunkelweizen fermentation
« Reply #15 on: October 01, 2014, 03:41:32 PM »
Thanks for the advice. It was about 800-850ml, so I'm guessing I should be ok.
Thanks again.

The yeast whisperers say to not start in less that 1L

Is that to say that no starter should ever be started with less than one liter of wort, or that final volume should be no less than one liter?
One liter seems like a big starting starter to start with.

the concern is that the yeast will stop reproducing if the cell density gets too high. If you pitch say 200 billion cells into 1 liter of wort (I am not 100% on the numbers so don't quote me on specifics) the cell density will be too high to gain anything. the cells will settle in, look around and just start eating rather than reproducing.

If you pitch a reasonably fresh vial of liquid yeast into 1 liter of wort you are somewhere < 100 billion cells. So assuming my numbers are correct you could still realize a doubling of cell count. If the vial is a few months old you're talking more like 50 billion cells so then 1 liter is sufficient for two doublings.

but overall you cannot grow more than 200 billion cells in 1 liter of 1.040 wort.

I get it now. Thanks
Jonathan W.
Snohomish WA

Offline 69franx

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Re: Dunkelweizen fermentation
« Reply #16 on: October 01, 2014, 03:54:46 PM »
This is all good info to read about. Thanks to all who contributed


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Offline archstanton

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Re: Dunkelweizen fermentation
« Reply #17 on: October 01, 2014, 05:04:21 PM »
Even with a 1/2 liter starter and 100 billion cells, there  still will be a little growth. More important to growth is cell health, and cell health will increase, as well as a jump start in metabolism which will get fermentation going faster.  Growth seems to be all anyone ever thinks of, it is only one side of the coin.

Offline morticaixavier

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Re: Dunkelweizen fermentation
« Reply #18 on: October 01, 2014, 05:28:36 PM »
Even with a 1/2 liter starter and 100 billion cells, there  still will be a little growth. More important to growth is cell health, and cell health will increase, as well as a jump start in metabolism which will get fermentation going faster.  Growth seems to be all anyone ever thinks of, it is only one side of the coin.

I'm not sure that a too small starter will necessarily lead to healthier cells though. When those cells were grown they developed a reserve of glycogen as one of the last things they did before going dormant. If you wake them up in a small, limited environment the first thing they do is use up that reserve while they are getting accustomed to the new surroundings. If there isn't really enough sugar for them to do anything once they are there they just use up their reserves and then you pitch them into a big volume less prepared.
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Offline majorvices

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Re: Dunkelweizen fermentation
« Reply #19 on: October 01, 2014, 06:27:49 PM »
Even with a 1/2 liter starter and 100 billion cells, there  still will be a little growth. More important to growth is cell health, and cell health will increase, as well as a jump start in metabolism which will get fermentation going faster.  Growth seems to be all anyone ever thinks of, it is only one side of the coin.

That's actually not exactly how it works. If your starter is too small you will have the yeast cells expend their glycogen reserves and weaken the cell walls which will cause problems when budding. If your yeast is very old then the vitality will be low and a small starter might be a better approach.
« Last Edit: October 01, 2014, 06:33:02 PM by majorvices »

Offline archstanton

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Re: Dunkelweizen fermentation
« Reply #20 on: October 01, 2014, 07:19:38 PM »
I am not responsible for your misinterpretations of my statement. ;-)
I will just quote right out of the yeast book by Chris White
"A high concentration of yeast in a small amount of wort results in very little growth...While the cells do not multiply much when the inoculation rate is this high (100 billion in 1/2 liter) it can still benefit existing cells. The take up of sugar, nutrients, oxygen, and the production of compounds such as sterols, improve cell health. Starters rarely have a negative side; even if there is little yeast growth, a starter helps to revive yeast for fermentation by activating metabolism, and therefore fermentation starts faster"

"The most important thing to know about starter size is that the inoculation rate affects the rate of growth...It is not the volume of the starter that is important, but how many cells you add in relation to that volume"

If I had a laboratory fresh culture with 100 billion cells, I would not make 1/2 liter starter with it. There would be no point. If I had 100 billion older cells low on vitality, it could certainly be the way to go.