The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

bread yeast vs wild yeast vs brewers yeast

stickyfinger's picture
stickyfinger

bread yeast vs wild yeast vs brewers yeast

Hey, i've been trying to find info about bread yeast such as instant yeast that all of us have used vs wild yeast or brewers yeast.  why does bread yeast work so well and so fast to make dough turn into a huge beautiful volume of "airy" mass compared with other yeast?  does it have amylolytic capabilities that far surpass other yeast?  

 

If i used 7g of bread yeast in one batch and 7g of brewers yeast in separate batches, i'm sure the bread yeast would way outperform the brewers yeast.  why?  is it the sugars they desire?   

 

is it possible to grow up bread yeast in culture and create a slurry that i can use for bread and propagate continuously instead of buying it at the store.  

Note:  i know how to make sourdough bread, wild yeast starters, etc.  i'm talking about keeping a very active live culture of commercial bread yeast that i can tap at will and build up again...

idaveindy's picture
idaveindy

Even though bread yeast and brewer's yeast are (generally) the same species, Saccharomyces Cerevisiae, they are different breeds or strains within the species.  (Though not all brewer's yeast is Saccharomyces Cerevisiae.)

Like how all dogs are dogs, but there are different breeds for different purposes.  A beagle can't run as fast as a greyhound.

Wild yeast is a different species than Saccharomyces Cerevisiae.  (Thank-you, mwilson.)  The so-called "wild yeasts" in home-based starters are not usually Saccharomyces Cerevisiae, but when they are, they would almost certainly be different strains of it than are found in commercial bakers yeast and in brewers yeast.

(added:)  The names of some specific species found in sourdough starters can be found in Sourdough School, by Vanessa Kimbell, and The Bread Builders, by Daniel Wing and Alan Scott, and at https://en.wikipedia.org/wiki/Sourdough

Go to the wikipedia entry for Yeast, then explore the different kinds, brewers, bakers, etc.

--

To illustrate different strains/varieties/breeds, If you haven't done so, request a dried culture from www.carlsfriends.net, and rehydrate it, and when mature, make some bread with it.  It looks, feels, smells, and tastes different from any other commercial yeast or sourdough yeast (purchased, or made from scratch) that I have used.  I have used four different sourdough cultures: 2 different ones from www.culturesforhealth.com, a home grown one, and Carl's.  Plus regular ol' Fleishmann's. 

mwilson's picture
mwilson

 Not quite right.

"Wild yeast is a different species than Saccharomyces Cerevisiae."

See my comment below. Saccharomyces cerevisiae has evolved along side human activities, such as making beer, bread, wine etc.

It is a key species! And naturally selected. It's only in modern times that strains can be grown as a pure cultures.

mwilson's picture
mwilson

Like Dave said.

Saccharomyces cerevisiae is key a species that is responsible for the fermentation of many foods and beverages, however different strains are better suited to their intended purpose than others.

Bread, beer and wine are all commonly fermented by S. cerevisiae yet representative strains would be suited to each type of fermentation.

Bakers yeast is selected for CO2 production and neutral flavour while brewers yeasts are selected more for flavour and specific functions like ethanol tolerance.

The term "wild yeast" is a bit of misnomer but it means to select yeast without inoculating. Wild yeast could be anything including S. cerevisiae.

All yeasts were once "wild".

I remember Jimmy Doherty trying to make beer from bakers yeast and bread brewers yeast. Of course the results were not optimal.

SirSaccCer's picture
SirSaccCer

If you don't mind a slightly technical discussion, researchers at NC State recently gave a virtual seminar about the evolutionary history of baker's yeast, and they get into some detail about that very topic. For the discussion of bread yeast, skip to 9:00 (but the whole thing is really cool). As the above posters have said, it all comes down to selecting yeast for desirable traits, which come from a really colorful palate of genetic diversity. I recommend checking out all of the lecture in this mini-seminar series, by the way; they are really informative! and diverse, not all about yeast.

I work in a lab where we study basic biology and genetics using yeast, and I have wondered the same thing as you--could I propagate a commercial strain of yeast continuously? It's a tempting experiment to try out, but I suspect it would not work very well, for at least two reasons. 1) Like many microbes, yeast have a tendency to mutate frequently and propagate quickly, which can lead to a rapid loss of the desirable traits for which they were selected in the first place. By an analogy given above, if you could watch a colony of purebred greyhounds wildly multiply over several dozen generations, without carefully selecting the parents of each new generation you would probably wind up with a dog only vaguely resembling its ancestors. If you propagate a slurry of commercial yeast for more than a few days or a week, especially in a home kitchen, I think it is all but guaranteed that they would quickly change for the worse. 2) Along those lines, the technology required to maintain desirable yeast strains is relatively simple but still much better suited to the lab than the kitchen. Think Petri dishes, shaking incubators, and carefully-prepared optimal growth media--nothing too crazy, but not really something you can do at home. With microbes that love to mutate and reproduce quickly, it is difficult to consistently achieve the desired result without microbial culturing technology and techniques. Also, I assume from my lab work that once major yeast producers have a desirable yeast, they take utmost care to isolate it under sterile conditions and then store it in a really cold freezer for decades at a time. These "parent" strains will then be the source of their large scale productions. This would be key to the consistent results that you get from such yeast when baking, brewing, etc.

albacore's picture
albacore

OK, at the moment, there may be a shortage of bakers yeast for home bakers, but normally it is plentiful and a very minor cost compared to the flour you will be using to make the bread. The dried version is also very user friendly because it can be kept in the freezer for years and yet removed in a moment and ready to use in 5 minutes.

On a bigger picture note, bread fermentations don't have to use s. cerevisiae. I have made good bread with Saccharomyces bayanus wine yeast and another option is Torulaspora delbrueckii - I haven't tried that one.

One of the upcoming Fermentology mini-seminars dealing with novel bread yeasts should be an interesting watch for those interested in this area. (June 11th: Baking Yeasts of the Future)

Lance

SirSaccCer's picture
SirSaccCer

To be clear, I'm not advocating for the idea of propagating commercial yeast at home. I was just participating in the thought experiment posed by OP. It takes me 6 months to go through >200g of commercial yeast, so it is almost cheaper per unit time than even salt, let alone flour. For me, the act of propagating yeast could be fulfilling from a scientific and technological standpoint, but I have better things to do with my time.

I have not experimented with different yeasts in baking but it sounds like fun! I think it may have been an earlier post by you through which I found the enjoyable and informative Applied Fermentology mini-seminars (my previous link was to one of those). So thanks for that!

stickyfinger's picture
stickyfinger

Hey all!  Thanks for the replies.  I'm going to look at that seminar for sure!  That's exactly what I was looking for.  

 

On a side note, I finally received my instant bread yeast in the mail yesterday, 2 lbs in vacu-packs!  I was so excited!  Onward to making bread!