Why is that a credibility problem? According to the explanation from WL on line they changed the name of the product when they became aware of the true nature of that yeast.
The only credibility issue I can think of is the connection to Zainashef. LOL [emoji12]
same as vials. depending on LHBS…$6-$8
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Damn, my LHBS is more like $12 for yeast.
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Wow. Order several online and the cost of shipping is more than covered.
I don’t know if “purity” is an issue to worry about, but I bet it saves them money. I personally hate the pouch form factor.
Some of the early answers they gave was that they were aware it wasn’t brett but labeled it as brett anyway. They only changed it after getting called out. Then suddenly there was a study they just happened to be doing to fix it.
Same people who looked at Trois took a look at their lacto offerings and found yeast. That’s a problem for people trying to sour wort or beer.
Both of these issues have appeared in a matter of months. Who knows what other problems are floating around in their products. I don’t know that growing yeast in a pouch is the solution. I’m not even sure for what problem it is a solution.
So far this single pouch pitch is performing almost identically to a vial pitched into starter and then pitched into wort. Lag times, fermentation and krausen activity. Little over 48 hours and going strong.
Finished product will be the next gate.
Curious and thinking about many yeast discussions on this forum. Starter, no starter, stir plate, no stir plate, health quality vs quantity…etc. will fresh healthy yeast in lower quantity perform as well or better then a stressed or less healthy larger quantity starter? Interesting thoughts that lead me to give it a shot.
What I like about the pure pitch technology is that it can maintain aseptic conditions all the way through packaging. The old White Labs and the current Wyeast production processes, while very clean, are not fully aseptic.
and your thoughts on fermentation with yeast in its healthiest/optimal state at lower volumes - for instance in this case one pure pitch pouch (all white labs says is at least 100B, so not sure how many) vs making a starter to get the target of 200B?
As I have mentioned many times, yeast cultures are like nuclear weapons in that one only needs to be close to one’s target. The difference between 100B and 200B cells in a normal gravity fermentation is one replication period. What matters is initial yeast health, and it appears that the product is living up to the hype. I was impressed with how healthy the yeast looked in the brewery size pure pitch packages while visiting White Labs.
Yes I recall all of the discussions related to this and that’s what pushed me to give this a shot.
Curious- do you have the means to get a count on a pure pitch pouch?
I don’t use White Labs yeast very often, but isn’t that the same cell count as the tubes (100 billion that is)?
Yeah that’s my question. Pure pitch says “at least 100b”. I’m curious what perhaps is their target- 125,150??? Mine was less than 2 weeks old when I used it.
My understanding is that they package a fixed volume, and that’s why different strains will have different cell counts.
Anyone with a cytometer should be able to. I’d volunteer, but I don’t see myself buying new yeast any time soon.
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A quick and dirty way to estimate the number of cells in a liquid culture is to measure the volume of thick slurry in the culture. A traditional brewery crop contains around 40% yeast solids. At that percentage of yeast solids, 1ml of slurry contains approximately 1.2 billion cells. White Labs slurry is pretty darn close to being pure yeast; therefore, 1ml contains approximately 100 / 40 * 1.2 = 3 billion cells. If anyone ever wondered what the basis was for the 100 billion cell claim, well, a White Labs preform contains approximately 35 milliliters of thick slurry. At 3 billion cells per milliliter, 35ml of pure yeast contains approximately 35 x 3,000,000,000 = 105 billion cells. The keyword here is “approximately” because not all yeast strains have the same size cells.
Once again, cell health is more important than cell count unless we are talking about a cell count difference that is more than a few replication periods. One hundred billion young viable cells that are reasonably healthy will make quick work of 19 liters (5 gallons) of normal gravity wort. People have to remember that White Labs has always targeted the direct pitch crowd. Pitching a White Labs culture into 1L or 10% w/v (1.040) wort does not increase the cell count as much as it allows the cells to come out of quiescence in a high cell count to wort volume environment.
I know that a lot of brewers do not want to hear what I am about to say, but allowing a starter to ferment out, so that the supernatant can be decanted is not a good practice from a yeast health point of view because it places the culture back into a quiescent state. A well known brewing book author has stated that one should allow a starter to ferment out because the cells are healthier due to increased glycogen and trehalose stores. Nothing could be further from the truth. Yeast cells store these carbohydrates as the usable carbon (sugar is carbon bound to water) in the medium nears exhaustion much in the way that bears put on fat before the winter. Yeast cells also undergo a morphological change where their cell walls thicken. This combination results in cells that are denser than cells in an active fermentation. Yeast cells then slow their metabolism and enter a state known as quiescence. These changes are a survival mechanism.
What makes a yeast cell healthy is not glycogen or trehalose stores. It’s ergosterol and unsaturated fatty acids (UFA). These compounds make the cell plasma membrane more pliable, which, in turn, makes it easier for cells to pass nutrients in and waste products out of the cell wall. Plasma membrane pliability determines the quality of the ferment as well as alcohol and high osmotic pressure tolerance. Alcohol and high osmotic pressure have almost the same effect on yeast cells because both conditions result in dehydration and the lost of something known as turgor pressure. Turgor pressure is the cellular force that holds the plasma membrane against the cell wall.
The moral of the story is that one should pitch at high krausen if possible. High krausen marks the end of the exponential growth phase. Beyond this point, all replication is for replacement only. As the mother cells that were alive while O2 was still in solution share their ergosterol and UFA reserves with all of their daughters and their daughters share their ergosterol and UFA reserves with their daughters and so forth, we want to minimize unnecessary replication. Replication beyond high krausen is unnecessary replication.
It really did worked for me. I liked it and read the both papers. Thanks for sharing.
The White Labs website says 2.5 Billion cells per ml. Yeast and Fermentation | White Labs
Anyone know the volume of the package?
Today I’m Brewing another test with one pure pitch of wlp001 at 1.060. 1.050 batch last week has done very well, finishing 1.010 as targeted, and sample tastes great with no signs of any off tastes or smells.
Per Mark, 35ml is the approximate volume.
So, I am starting to think that top cropping is worth considering for yeast harvest as opposed to slurry from a fermenter? Especially if one does not use conical fermenters with dump valves…
That figure is more than likely a conservative statistical mean that accounts for the difference in yeast cell size and varying amounts of non-yeast organic matter (the last thing that White Labs needs is some hot shot home brewer with a microscope and a hemocytometer posting that they are inflating their cell count numbers).
With that said, the difference between 2.5 and 3 billion cells per milliliter is in the noise due the nature of exponential growth. As I have mentioned many times, yeast biomass grows at a rate of 2n, where n is the elapsed time since the culture left the lag phase divided by the length of the replication period. The reason why the biomass grows at a rate of 2n is because yeast cells reproduce by budding, a process where a smaller daughter cell forms on the cell wall of its mother cell and then splits off.
If we look at the problem from a growth point of view, we can see how insignificant a difference of 0.5 billion cells per milliliter is in the grand scheme of things.
number_of_replication_periods_necessary_to_reach_saturation = log( saturation_cell_count / pitched_cell_count) / log(2)
The maximum cell density (saturation) for 1mL of wort is approximately 200 million cells; therefore, the maximum cell density for 19 liters (5 gallons) of wort is 19,000 * 200,000,000 = 3.8 trillion cells.
3.8 trillion cells = 3,800 billion cells
35 milliliters of slurry that contains 2.5 billion cells per milliliter has a total cell count of 35 * 2.5 = 87.5 billion cells
number_of_replication_periods_necessary_to_reach_saturation = log( 3,800 / 85.5) / log(2) = 5.44
35 milliliters of slurry that contains 3.0 billion cells per milliliter has a total cell count of 35 * 3 = 105 billion cells
number_of_replication_periods_necessary_to_reach_saturation = log( 3,800 / 105) / log(2) = 5.178
Increasing the pitched cell count to 200 billion cells
number_of_replication_periods_necessary_to_reach_saturation = log( 3,800 / 200) / log(2) = 4.25
Therein lies the reason why yeast cultures are like nuclear weapons in that one does not need to worry about being all that close to a calculated required cell count. It’s also why the results from yeast calculators should be taken with a grain of salt.
Like all living organisms, no two yeast strains behave exactly the same under the same conditions. A strain will often behave differently in different brew houses. The best way to discern the correct pitching rate for a given strain in one’s brew house is to pitch, observe, perform a sensory evaluation, take good notes, and repeat the process with a different pitching rate until the desired result is produced.
On another note, I am curious to know if White Labs separates 100% of the non-yeast solid organic matter from the medium. They definitely use an autoclaved growth medium. From what I can ascertain, the medium used to be malt extract based. The 20bbl brewing kettle that they recently installed is capable of 15 PSI above normal atmospheric pressure operation, and it appears to be plumbed such that it can pump autoclaved wort directly into the propagation facility.
Top cropping will limit the number of strains that can be employed in your brewery. Top cropping is best employed with true top cropping strains (i.e., strains that produce a thick, gooey yeast head). Additionally, unless the cropped culture is fed, top-cropped yeast has a more limited shelf life than bottom-cropped yeast because it is taken from the fermentation before carbon becomes limiting (i.e., the cells have not undergone the changes necessary to survive without a readily available food source). Top-cropping works best in breweries where the yeast is stored no more than a week without being repitched or at least fed.