Is it really true that one should not make a yeast starter from dry yeast, because you exhaust the yeast and blablabla or is this just one of those bullsh*t stories?
That’s how the story goes.
First time I used dry yeast I did a starter (because I didn’t know any better). As expected, everything turned out wonderfully. 
(probably just wasted effort on my part)
Yes, that’s all true IMO. But to me, the I bigger reason is that you don’t need to.
The one time when I would advise it is for krausening to get rid of diacetyl or the finishing gravity being too high. Sprinkling dry yeast on either of those would likely be fruitless. But for initial pitch, you never need a starter for that with dry yeast. It’s the big advantage.
I know you don’t have to. I don’t even use dry yeast a lot. I just want to know that if you make a starter from dry yeast, you weaken it considerably… Obviously the proof would require an experiment that I’m not willing to do personally 
For krausening, you need to add actively fermenting wort, not just yeast.
Well yes of course.
After I typed that, I realized that’s what would be happening.
I would not equate “making a starter with dry yeast” to “weakening it considerably”. It’s just not necessary for most 5 gallon batches; now if you were aiming for a 10 gallon batch of significant gravity and only had 1 sachet of dry yeast on hand then a starter should help in this regard.
The nice thing about dry yeast is that (paraphrasing from S. Cerevisiae and the Lallemand website) it is propagated in a manner that results in high levels of ergosterol and UFA reserves. As such, you do not really need to aerate/oxygenate your wort on an initial pitch. The other nice thing is that there are a lot of cells in each packet.
I think making a starter with dry yeast is less about weakening the yeast and more about just not being necessary, since you already have a good amount of fully charged cells.
What about making a big starter from dry yeast and only pitching half, and keep the rest for a future brew day, say a week or two later?
Make a five gallon starter, say a 1.050 OG beer. Use the yeast cake for 10 gallons of the big beer. Aerate the big beer, and add nutrients.mthis has worked for me.
ok, please help me understand. I have always been a fan of creating a starter culture to pitch into my beers, whether I use a liquid or dry yeast to start with. I use 500mls of wort, and pitch the dry or active liquid yeast (bulging packet) into it, a few days before brewing, hoping to allow it to reach the maximum logarithmic stage of growth to pitch into my 5 gallons of wort.
My thinking is that the entire 500mls will be filled with loads of yeast in their most prolific phase of growth, and the starter culture will contain tons of enzymes from the yeast ready to continue to cleave sugars into yeast food, so that I get a vigorous, almost violent, start to my fermentation so as to help avoid contamination, get a good start, etc.
Maybe it is just me, but I feel better when I Pitch a starter that is showing good signs of growth into my just-made wort.
Again, please help me understand if I am just wasting my time preparing a starter culture. I have never pitched only dry yeast into my just-made wort.
In theory, there isn’t much point in making a starter with dry yeast for the reasons explained above: you already have a large cell count of yeast with healthy UFA and ergosterol reserves that require little or no additional oxygen on the initial pitch.
With liquid yeast, you are generally starting with a lower cell count and the cells do not have the same levels of UFA and ergosterol due to the method of propagation. You can increase the amount of cells you are pitching by using a starter (though I don’t think you are going to see much growth pitching a full smack pack into a half liter starter).
For some interesting information on growth, check out this blog post: Yeast Cultures are Like Nuclear Weapons | Experimental Brewing
See also reply #56 in the following thread: https://www.homebrewersassociation.org/forum/index.php?topic=24460.msg312443#msg312443
Then you have the choice of pitching the starter at high krausen (when UFA and ergosterol reserves are supposedly higher) or waiting until the starter ferments out, decanting, and pitching just the slurry (when reserves are supposedly lower).
There has been a ton of discussion on these topics here recently, though perhaps not much consensus. A good chunk of it was posted by user S. Cerevisiae. If you search this forum for his posts using key words like “ergosterol,” “maximum cell density,” or “morphological changes” you will find a lot of information.
As an example, see reply #48 in the following: https://www.homebrewersassociation.org/forum/index.php?topic=24041.msg306967#msg306967
See also reply #5 in this thread: https://www.homebrewersassociation.org/forum/index.php?topic=25207.msg323689#msg323689
Thanks for the reply, good information and articles. Helps me understand better the where I need to be with my pitching yeast.
Is that also true for big beers: over 1.100?
Below Dr. Clayton Clone states that Lallemand dry yeast has sufficient lipids for 3 to 4 growth cycles. In theory, if you require more cells than that, you should either pitch more than one packet or add additional oxygen at some point in the fermentation (that is also touched on in the below).
http://www.lallemandyeast.com/articles/crabtree-effect-and-overflow-metabolism
To paraphrase SC again, the osmotic pressure placed on yeast cells in a high gravity wort is another reason to pitch more cells when brewing high gravity beers. See reply #46 in this thread: https://www.homebrewersassociation.org/forum/index.php?topic=24439.msg311523#msg311523
Here’s some more info from Dr. Clone in response to a question concerning rehydrating but which also seems applicable to the question of making starters with dry yeast:
“We recommend that the rehydrated yeast be added to the wort within 30 minutes. We have built into each cell a large amount of glycogen and trehalose that give the yeast a burst of energy to kick off the growth cycle when it is in the wort. It is quickly used up if the yeast is rehydrated for more than 30 minutes. There is no damage done here if it is not immediatly add to the wort. You just do not get the added benefit of that sudden burst of energy.”
I’m a primary user of dry yeast but they have to be handled properly. Or at least the Lallemand does. I expect they all have similar rehydrating and pitching characteristics.
Benefit is an “instant-starter” so making a starter out of dry yeast is redundant. However, mishandling causes problems enough to make you wish you’d made a starter. Reading the product sheet reveals essential tidbits like attemperating the yeast pitch to wort temp in 10* increments or risk yeast mutations in the case of Munich yeast.
My 2 cents.
As already stated repeatedly above, dry yeast is “prepared” to get cracking the moment it gets rehydrated. It’s primed and good to go as it is, ergo it is unnecessary -and in fact downright detrimental to yeast performance to make a starter from a pack of dry yeast. Not sure if this applies to strains like saflager as well though.
As to “one should not”…that sounds a bit silly. I mean, you can easily rack a second beer on top of a yeast cake originating from a previous fermenation started with dry yeast. That’s not the same thing as a starter but as close to it as I care to reckon. You could just as successfully make a starter from a single packet to arrive at a cell count which would be more suitable for (say) a big-ass imperial stout, or a 10 gallon batch instead of 5.
From my understanding, it’d still not be as efficient as simply ptiching more packets, but at the end of the day, the packets contain healthy yeast, which you can use either to brew or to propagate.
Euge, thanks to you, I have learned the word “aliquot.” In practice, it sounds as if attemperation would only need one interval (if the yeast is ca. 75f after 20 minutes, and your wort is even as low as 50f, and intervals are 50f, then it seems one dollop of wort for 10 minutes would do the trick??).
http://www.murphyandson.co.uk/datasheets/munich%20wheat%20yeast_tech.pdf