Dry and Liquid yeast abstract

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Brewpastor

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Jamil spoke recently on one of his shows of an abstract from a comparision of dry and liquid yeast. Jamil was stressing the use of liguid yeast over dry. I know there has been great debate on this issue and was interested to read the abstract. So I sent him a note and got the following response, which I pass along for your information.

Tom,
It was an ASBC paper. Here is the abstract:

ABSTRACT
J. Am. Soc. Brew. Chem. 60(3):135-139, 2002
Strains of freshly propagated ale and lager yeast were compared with identical dried strains during wort fermentations. While several factors remained within standard expectations and were favorably matched to freshly propagated yeast fermentation results, a number of undesirable characteristics were associated with the dried yeast brews, especially reduced viability. The Helm flocculation test and static fermentations showed that flocculation is affected by the drying process, especially with lager strains. Also, dried yeast seems to induce a greater amount of haze in suspension, and the fermentation has a considerably less stable foam than fermentations with the fresh yeast samples, which may be due to the increased levels of extracellular proteinase found. It is suggested that many of the effects observed are a result of pitching high levels of dead yeast into the wort and that this could be alleviated by increasing the viability of the dried yeast, possibly by propagating on carbon sources such as maltose to increase levels of trehalose, a reported stress protectant

brew strong,
JZ
 

mrkristofo

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whoa boy...might want to reformat that

Edit: The paper is actually quite a good read. Ale Yeasts used are S-04 & S-33 (Dry and Fresh). Lager yeasts are S-23 & S-189 (also dry and fresh).
 

c.n.budz

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I use dry and liquid yeast depending on what I'm brewing. While I've never gotten as vigorous of a fermentation with dry yeast as I get with liquid, I've also never made a beer with dry yeast that I felt was flawed due to the yeast. Maybe I'll start making starters with dry yeast to see if I can notice a difference
 

cheezydemon

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c.n.budz said:
I use dry and liquid yeast depending on what I'm brewing. While I've never gotten as vigorous of a fermentation with dry yeast as I get with liquid, I've also never made a beer with dry yeast that I felt was flawed due to the yeast. Maybe I'll start making starters with dry yeast to see if I can notice a difference
The problem most people have with seeing that liquid is better is this statement:"I have never noticed any ill effects from using dry yeast"

It is impossible to notice an effect of any kind without comparison. How would you know that a brew could have been a little better if it still tastes pretty good?

That is like saying, "all of the lead I ate as a child never hurt me any! my IQ is 112!", when the poor sap doesn't realize that his IQ is 5 or 6 points lower because of it. How would you ever miss it? But it is gone nonetheless.
 

Soulive

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cheezydemon said:
The problem most people have with seeing that liquid is better is this statement:"I have never noticed any ill effects from using dry yeast"

It is impossible to notice an effect of any kind without comparison. How would you know that a brew could have been a little better if it still tastes pretty good?

That is like saying, "all of the lead I ate as a child never hurt me any! my IQ is 112!", when the poor sap doesn't realize that his IQ is 5 or 6 points lower because of it. How would you ever miss it? But it is gone nonetheless.
Someone needs to do a split batch with US-05 and 1056/001...
 

cheezydemon

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Good suggestion. I have done experiments, but they were long ago and I didn't record any hard data.

My results are just that I have only used liquid since and I have never looked back. (except to add yeast at bottling or in a real emergency. Dried keeps easy and is handy in a pinch)
 

Bobby_M

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If dry US-05 is just as good as liquid 56, there would be no reason to use liquid. I agree that it's a good split batch but I can anticipate the controversy now...

You didn't pitch equal amounts.
Your starter was too small.
The style of beer you chose doesn't accentuate the differences enough.

ETC... it's something I definitely want to try though.
 
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Dried is easy and I am sure good dried yeast work fine. But I have always felt I was not utilizing the very best ingredients if I used it. The competition results at Nations seems to support the use of liquid yeast for that level of beer quality. I am not trying to tell anybody what to do, only passing along some current data from a trustworthy source.
 

srm775

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cheezydemon said:
The problem most people have with seeing that liquid is better is this statement:"I have never noticed any ill effects from using dry yeast"

It is impossible to notice an effect of any kind without comparison. How would you know that a brew could have been a little better if it still tastes pretty good?

That is like saying, "all of the lead I ate as a child never hurt me any! my IQ is 112!", when the poor sap doesn't realize that his IQ is 5 or 6 points lower because of it. How would you ever miss it? But it is gone nonetheless.
This would only be true if someone has never tasted a similar beer brewed using the two different yeasts. The truth is that most people have tried beers using liquid and dry. Also, there are certain factors that can be easily identified that can be directly traced to the yeast and not just procedural, such as fruit flavors in a lager etc.

That said, I nearly exclusively use dry yeast. And, contrary to Jamil's results, I notice much more vigorous fermentations using dry vs. liquid (even with a starter). I think if you ask most people that use dry, they will tell you that they usually see activity within a few hrs. of pitching and it usually ferments out within a few days. However, everytime I use liquid (with a starter) I experience considerable lag-time and a longer, slower ferment.
 
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long and slow does not automatically equal bad fermentation, nor does short and fast equal good. The important thing is the yeast be healthy, and enough viable cells are pitched.

Also, the abstract and the study isn't Jamil's but one put out by the American Society of Brewing Chemists.
 

cheezydemon

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Absolutely. I respect everyone's right to choose. But "fruity Lager"?? That is not a wet or dry trait, but a lager trait.

Brewing 2 different batches and using dry on one and wet on the other will not tell you anything, there are too many variables.

My statement holds true, unless you split a batch of wort and use two same strains one wet one dry, you can't make a judgement.

You can't say that the IPA with the wet was a little sweet and the porter with dry was spot on and make a judgement.

You can't even use the same recipe (except maybe in a lab) and try to make inferences.
 

srm775

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Brewpastor said:
long and slow does not automatically equal bad fermentation, nor does short and fast equal good. The important thing is the yeast be healthy, and enough viable cells are pitched.
Never really thought it did equal a bad fermentation, but it specifically mentioned vigorous nature of the fermentation. I think it's evident that a fermentation that lasts 7 days to reach FG isn't as vigorous as one that takes 3 days to reach the same FG.


cheezydemon said:
Absolutely. I respect everyone's right to choose. But "fruity Lager"?? That is not a wet or dry trait, but a lager trait.
Well, I've read of people's experience using Safale 23 and noting it had a fruitier finish than the equivilant WP/Wyeast. One experienced brewer (sits on the board of the AHA) noted he did the same beer under the same conditions. I've also heard that complaint from other on various boards regarding that yeast compared to it's wet counterpart.

cheezydemon said:
Brewing 2 different batches and using dry on one and wet on the other will not tell you anything, there are too many variables.

You can't even use the same recipe (except maybe in a lab) and try to make inferences.
I think that if you follow a normal procedure (I think most brewers are pretty regimented about how their brew days go) and tried-and-true recipe but only alter the yeast (let's say Wyest 1056 vs Safale-05) between one batch and the other and taste differences, then you could very easily attribute those to the yeast.

Think about it, if you're altering the single most important ingrediant in your recipe between to different batches, then it's quite easy to to see that the change would be due to the yeast. It would be like using Safale-05 vs Safale-04. You wouldn't say that "no, there's too many variables, you can't be sure it's the yeast"

Again, that being said, I don't believe all the hype about WLP & Wyeast and think that dry yeast does an excellent job and produces some superior beers.
 

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I have to agree that the only way to know for sure is to split the batch and make sure all other variables are equal between the two samples. This is simple science. I use dry yeast 95% of the time and I'd never suggest that it's better. The most I'd do is say the beer is good enough. In a way, I'm scared to find out that liquid yeast is superior (from my own tastebud's perspective). It means I'll be out some bucks.

Anecdotally, the best beer I've ever made used WLP001 that I collected from a local brewpub. I'll never know if it was the yeast.
 

FlyGuy

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From a purely scientific point of view, splitting one batch of wort and fermenting with dry vs. liquid yeast would be the best way to accomplish this experiment. It could also be done by replicating the treatments and brewing an identical recipe over and over, using dry yeast for half the batches and liquid for the other half following random assignment. The number required replicates would depend on the consistency of the wort properties, and inconsistencies between batches would even out across the two treatments. So possible, but not really practical.

Although the simple split-the-wort approach has clear merits, one would have to be very careful about generalizing conclusions about the 'better' beer made from dry vs. liquid yeast. In some ways, it is like comparing apples to oranges because the process of yeast preparation will determine its individual performance, and that cannot be controlled. For example, if one were to do the experiment without rehydrating the dry yeast, I bet the liquid yeast would win in that trial. If another trial were performed, and the dry yeast was rehydrated this time, the comparison between dry and liquid might yield more subtle differences. Or, imagine that different yeast starter volumes were used for the liquid yeast preparation. Etc., etc.

In the end, there is a wide array of preparation parameters that brewers follow when using both liquid and dry yeast, and the outcome of the comparison of the two yeasts is probably highly dependent on the individual brewer's process. So a general, across-the-board comparison between liquid and dry yeast is going to be difficult unless there is some substantive, over-arching difference between the two yeasts that is not dependent on yeast preparation methods (e.g., dry yeast always yields a peculiar off-flavour regardless of how it is used). I think we have already seen evidence from the collective experience of members on this board that the differences between liquid and dry versions of the same yeast are subtle, so a general, over-arching difference is unlikely to be detected.

I think that this is a test that everyone would have to do for themselves following the methods they prefer to use when preparing yeast. If everyone did this, I think it would be very likely that differences perceived by some would not be apparent by others, and that would actually make sense.

In summary, this would be an excellent experiment to try at home, but recognize that 'your mileage may vary' depending on your process.
 

Bobby_M

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Yeah, let's not forget that "better" is extremely subjective. You would hope the test would have ABOUT the same number of cells pitched, but I don't know any casual brewers that are capable of testing cell count prior to pitching. I would think rehydrated (fresh) dry yeast would be about the same as a vial of liquid stepped up to 1/2 liter starter. At least that's how I would do it. I'd also keep the beer pretty light and in the 1.040-50 area. Maybe a blonde or lightly hopped pale ale.
 

Alamo_Beer

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Just to throw a few monkey wrenches in....

How does/would washed yeast fit into this? What about washed dry yeast? At that point I handle it like a liquid yeast...

What do you think?
 

Bobby_M

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In general, I think the argument is that once yeast is dried, it takes on some inherent flaw but I'm not sure about that. It has been suggested that yeast can mutate in just a few generations. If that's true, I assume the drying process could influence an earlier and more widespread mutation. Of course, that also assumes mutations are inherently undesirable in all cases, which I doubt is true.

I think it would be much harder to experiment with washed yeast because now you really don't know how to measure cell count and comparing two samples that may have widely different pitch rates is just flawed.
 
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