Does bread yeast exist?
Norwegian baking yeast. Oslo, Norway
The title makes it sound like I've lost my mind, because of course bread yeast exists. You've all seen it sitting on supermarket shelves. But I've started to wonder whether what's sold as bread yeast really is a separate kind of yeast, or whether they're just brewer's yeasts that have changed profession.
As I started looking more carefully at farmhouse brewing I started finding that a surprising fraction of today's farmhouse brewers use baking yeast to ferment their beer. And they get really good beer out of these yeasts. Here's a quick list of places where I know farmhouse brewers use baking yeast:
- In Stjørdal, Norway many use Idun Blå.
- On Gotland, Sweden they typically use Kronjäst.
- In Finland the sahti brewers usually use Suomen Hiiva.
- In Estonia the koduõlu brewers usually use one of two brands of bread yeast (one of those is Suomen Hiiva under a different product name).
- In Latvia Ugis Pucens used the local bread yeast.
- In Lithuania some farmhouse brewers use baking yeast.
- In Russia, Dmitriy Zhezlov's farmhouse ale fermented with baking yeast was better than the one with brewer's yeast. Marina Ivanovna also used baking yeast.
Given all the prejudice against baking yeast, that's quite a list of brewers in different locations all finding that baking yeast works well in beer.
Starter from Latvian baking yeast, Aizpute, Latvia
And it's not only me who thinks baking yeast can make good beer. Kristoffer Krogerus did a scientific evaluation of Suomen Hiiva and found it to be "perfectly usable for beer fermentations". Brulosophy also did a recent experiment with baking yeast and although people could tell the difference, 1 in 3 preferred the version with baking yeast.
So a lot of different bread yeasts really do produce good beer. Why?
Well, where does bread yeast come from, anyway?
Norwegian Ethnographic Research's 1952 questionnaire on farmhouse brewing has a question on what yeast people in the countryside used for baking. Pretty much everyone who answers that question says the same thing: they used the brewing yeast.
This may sound odd, but if you consider a farm in the time before it was possible to buy yeast this actually makes a lot of sense. Brewing produces more yeast than you need for brewing, so there would be a surplus of brewing yeast. And whatever yeast you put into your bread or cake goes into the oven and is killed. Brewing produces yeast, while baking consumes it.
The other Finnish bread yeast. Hartola, Finland
The farm would in fact not have a whole lot of other alternatives. They could use wild yeast. They could maintain a sourdough culture. Or they could use their brewing yeast. It seems they overwhelmingly did the latter. At least in Norway. Many of the Swedish and Danish answers say the same thing, so it seems it was no different there. Based on another sources this seems to also apply to Finland.
What's interesting is that in the cities the situation was basically the same. Many places the bakeries got their yeast from the breweries, for example in Vienna. In Copenhagen there was even a law saying breweries were required to give the bakeries yeast for free. One Danish questionnaire answer even says if you had a lot of (farmhouse brewing) yeast you could sell it to the baker.
All of this is very suggestive, but none of it proves that the baking yeast sold by yeast companies today comes from brewing.
But where could it come from? Well, it could be brewing yeast, or sourdough yeast, or distiller's yeast. But distillation has not really been around for very long. It was only in the 1400s that distillation took off in Europe, and in the Nordic countries it only started growing significant two centuries later. Very likely most distillers started off using brewers yeast.
(Interestingly, a recent study of the use of sourdough yeast for brewing found that those might also work, and that conceivably some sourdough yeasts might also have a brewing background.)
Dmitriy Zhezlov making yeast starter with baking yeast. Shitovo, Russia
The Gallone et al 2016 paper  includes a lot of data on the yeasts they studied, including their ability to ferment maltose and maltotriose. And what do you know: of the four bread yeasts analyzed, all four have good utilization of both these sugars, which hints strongly at brewing domestication. Three of those bread yeasts were Belgian, the origin of the last is given as "unknown".
That paper also shows that besides the two big families of brewer's yeast, called Beer 1 and Beer 2, there is another family they called "Mixed", consisting of beer yeast, distiller's yeast, and bread yeast. A later, more extensive, study  renames the group to "Beer/baking", because it seems to mostly consist of those two types of yeast. Which really does seem to indicate that there is a strong historic connection between bread yeast and brewers yeast.
In my archive I have scans of a Finnish notebook written by one W. G. Åberg in 1885, and it includes a recipe for pressed baking yeast, the same kind of cube that baking yeast is often distributed as today. The recipe very clearly says to start with beer yeast (though not what kind).
Mika Laitinen kindly summarized a Finnish book on the history of the Finnish yeast industry  for me, and says: "The earliest Finnish yeast factories produced both baker’s yeast and spirits. These factories brewed some kind of beer from grain, harvested the yeast, and then distilled the beer. The book doesn’t say what kind of yeast they were using but obviously, it was brewer’s yeast."
As Andreas Krennmair writes, the process for making pressed yeast, the form the first commercial bread yeasts were distributed in, was invented by a brewer, who used brewer's yeast.
Yeast starter from bread yeast. Kudymkar, Russia
So it does seem that what we know as baking yeast today could originally be brewer's yeast. One reason I'm so interested in where these yeasts come from is how they behave. The brewers using these yeasts generally ferment at typical farmhouse brewing temperatures of 30-40C. The baking yeasts also ferment very fast, and seem to have high alcohol tolerance. So these don't seem to be normal commercial beer yeasts. Could it be that some of these yeasts are originally farmhouse yeasts? If so, that might help us fill out the family tree of farmhouse brewing yeasts and get more of a handle on what kind of yeast people were using in the areas where farmhouse yeast no longer exists. It might also help us work out how the various kinds of farmhouse yeast, such as kveik, evolved.
Of course, without direct proof we can't do that. The best way to get it would be to ask the producers directly where they got their yeast from. I have tried to do that, but unfortunately very few of them have answered yet. So one reason I'm writing this is to see if the blog post can help flush out some more answers from these producers. Or more knowledge from somewhere else. Here's a summary of how far I've gotten with the various producers:
|Suomen Hiiva||Finland||No change last 30-40 years. Origin uncertain.|
|Kronjäst||Sweden||Bought from a yeast bank in the 1980s|
|Idun Blå||Norway||Switched to Kronjäst in 2004. No answer yet to what they used before.|
|Lallemand||France||They're working on it|
|Pärm Euroferm, Salutaguse||Estonia||Same as Suomen Hiiva|
|Nordic Pärm (Vilmix)||Estonia||Haven't asked|
The two answers I have gotten, from Norway and Sweden, indicate that these waters may be muddier than they seem. From Idun Industri I got a reply from Inga Breivik where she says that "in the early days of yeast factories it often happened that employees bought bread yeast in grocery stores when they happened to be abroad. They took it back to the lab where it was tested to see how quickly the dough rose, how long it could be stored, and so on." She goes on to explain that if the tests were good enough the factory might decide to switch from its own production strain to one of these foreign acquisitions.
One intriguing thing about the answer from Idun is that those properties she says they were seeking, fast fermentation and ability to be stored for a long time, are exactly the ones that are characteristic of farmhouse yeast. So clearly baking yeast producers would naturally gravitate toward yeasts that are either farmhouse yeasts, or just like them.
Unfortunately, those answers also indicate it may be difficult to unravel this. On the other hand, perhaps the producers still have the originals banked away somewhere? And that answer from Suomen Hiiva sounds promising.
 NEU 3408, dated 1945, from just a few kilometers outside the town of Frederikssund, Zealand, Denmark.
 Hiivan tarina: Suomen leivinhiivateollisuuden vaiheet 1885–1970, Olli Vehviläinen. Suomen hiivatehtaitten myyntiyhdistys, 1970.
 Sourdough derived strains of Saccharomyces cerevisiae and their potential for farmhouse ale brewing, Martina Catallo et al, Journal of the Institute of Brewing, 20 February 2020,DOI 10.1002/jib.608.
 Domestication and divergence of Saccharomyces cerevisiae beer yeasts, Gallone et al, 2016, Cell 166, 1397–1410.
 A polyploid admixed origin of beer yeasts derived from European and Asian wine populations, Fay et al, PLOS Biology, 2019.
 Beer And Brewing In Pre-Industrial Denmark, Kristof Glamann, University Press of Southern Denmark, 2005.
I've written before about the kveik research paper by Preiss, Tyrawa, and van der Merwe
Read | 2018-09-12 16:27
The Norwegian University of Science and Technology (NTNU) in Trondheim started doing research and courses on brewer's yeast a little over a year ago
Read | 2016-09-06 16:30
Barm - 2020-05-04 16:03:49
I don’t think there is any doubt whatsoever that brewing and bread yeasts are one and the same. It is well documented in Britain at least that brewers gave or sold yeast to bakers. Around the end of the 18th century there was a sudden switch and bakers started propagating their own yeast. I have not looked into the reasons: we could speculate that it might be the use of black malt or heavier hopping by brewers, both making the yeast taste bitter, or perhaps the replacement of tiny local brewers by larger enterprises, so the trip to the brewery became less convenient. At any rate, for a few years a new trade of “barm-brewers” sprang up who specialised in propagating yeast for bakers. This in turn was displaced by the introduction of compressed blocks of yeast that we know as “fresh yeast” today.
James - 2020-05-04 16:22:13
Most bread yeasts will make phenolic beer, right? That is, we would call them "POF+" if they were brewing yeasts. If true, that would narrow it down but of course would leave open the possibility that they derive from POF+ brewing yeast (saison, hefe, whatever).
Lars Marius Garshol - 2020-05-04 16:45:20
@Barm: Many people do doubt it, although obviously I tend to agree with you. That brief history was interesting. Do you have any references to more detail?
@James: Yes, the bread yeasts I have any detailed knowledge of are phenolic. They're POF+ even though they're not beer yeasts. There are POF+ descendants even of the Beer 1 yeasts, so I'm not sure it really narrows things down that much. Unfortunately.
Barm - 2020-05-04 17:17:42
I don’t have it in great detail I’m afraid – it’s something I started looking at years ago but have never found time to research properly. This is from a paper given to the Royal Scottish Society of Arts in 1860:
The various modes as at present practised, may therefore be summed up thus:—
1st, The use of Leaven.—This system is not much followed here, the chief objections being, that the process is a tedious one, as well as the great danger of the dough passing into the acetous stage of fermentation before the bread is ready for the oven.
2d, Barm or Yeast supplied by Brewers.—Very objectionable from the quantity of hop contained in it, rendering bread so baked unpleasantly bitter.
3d, The Barm-breweries Yeast, which is prepared specially for the use of Bakers, and is very much and extensively employed.—This answers the purpose well, and where care has been taken, good and excellent bread is produced; the time required being, however, twelve or thirteen, or even sixteen hours, from the time of setting the sponge until the loaf is ready for the oven. There is also considerable danger of the bread having a peculiar flavour, approaching sourness, if the greatest nicety is not practised.
Lars Marius Garshol - 2020-05-04 18:13:47
@Barm: Perfect. Thank you!
Sacha Ikonicoff - 2020-05-04 19:37:45
I don't know if it is of any help, but a few month ago I brewed a beer with a starter containing the depot of a gueuze mariage parfait and a bit of saf-levure, the dry active bread yeast created by lesaffre. I fermented it without a lid at 20° for a month.
I suspect that saf-levure is responsible for the first fermentation, and wild yeast and bacteria took over after a while. The beer fermented well and quick, producing lots of co2 (as would be expected from bread yeast). The result is slightly sour but not vinegary. There was a slight smell of phenol but not too powerful.
What I think is interesting is that I actually do not like to use that yeast for bread as it is far too smelly when you use an appropriate amount, but it seems to be very apt for beer.
I could do a batch with just this yeast and see how fast it ferments and how it turns out.
Lars Marius Garshol - 2020-05-04 19:43:51
@Sacha: Thank you! This is actually the same baking yeast Dmitriy Zhezlov used. I preferred his beer with that yeast over the one with brewer's yeast.
Ed - 2020-05-05 21:29:20
Whisky distillers don't culture their own yeast, they get if from yeast companies now but used to get it from breweries.
Lars Marius Garshol - 2020-05-06 15:24:42
@Ed: I've started digging into that a bit now, and it seems it's a bit more complicated if you look at liquor producers more generally.
jm - 2020-05-06 16:04:18
> They could maintain a sourdough culture. Or they could use their brewing yeast. It seems they overwhelmingly did the latter. ... Based on another sources this seems to also apply to Finland.
Is it possible that you are overestimating how hard it is to discover and maintain a sourdough? To this day there are sourdough cultures that have been inherited from previous generations in Finland. I don't have any sources, but my impression is that yeast became popular here only with the industrialisation, before that it was mostly rye sourdough bread.
Lars Marius Garshol - 2020-05-06 17:40:19
@jm: It's not hard to start sourdough, and people clearly did it. But in Norway, Sweden, and Denmark when people are asked "did you use your brewing yeast for baking?" they answer "yes" if they answer anything at all. Clearly that was very common. Then a Finnish book on the history of yeast production says people in Finland generally used their brewing yeast. I'm going to have to assume that's correct.
Although I do agree that all these places people have definitely used sourdough, too.
Rob @ Spontaneous Gatherings - 2020-05-08 20:40:24
This is 100% speculation so feel free to put me in my place! Since reading this brilliant article the other day I've not been able to shake the idea that perhaps part of the use of hop tea that's often added post fermentation in some of these brewing regions was done so to avoid hop associated bitterness in the harvested yeast if it was to be reused in bread. I do remember that in Lithuania this was done so in the fashion of seasoning to taste but I can't help but wonder if maybe it also served a more utilitarian purpose.
Lars Marius Garshol - 2020-05-09 11:55:06
@Rob: It's not impossible that this might be part of the motivation for adding hop tea after fermentation. The reason that's usually given is that the alpha acid content of the hops were unknown, because these were not professionally grown hops. Nobody's mentioned that reason, but it could still be the case.
AndyStopford - 2020-05-13 11:29:04
I used to use bakers' yeast for brewing when I lived in Portugal. This came in 500g 'bricks' and there were two brands - unfortunately I can't remember the names, but one had a green label, one blue. The green stuff behaved exactly like top-fermenting brewers' yeast, fermenting very vigorously, and producing a massive cauliflower-like head (my home-made malt might have contributed to that). It flocculated pretty rapidly and effectively. The blue yeast was different - less spectacular krausen, less flocculation and I never thought the results were as good. I always assumed the green yeast was brewers' yeast and the blue something different, or maybe lager yeast. In the winter when temperatures were lower I never noticed any phenolic taste, and the results weren't bad under the circumstances, but as we entered summer the each brew tasted more and more 'rope-like' until it became undrinkable. If only we'd known about kveik yeast.
Karl Rüter - 2020-05-27 08:34:14
Kronjäst also produces "jäst för söta degar". Might be a separate origin?
Jäst för söta degar is supposed to be a better alternative when you bake things with higher suger content as Cinnamon rolls and alike.
I have tested the two kronjästs in a sahti-splitbatch. Unfortunately I seem to lost my brewing-notes, but I remember the sötadegar-yeast to have lesser amount of banana-taste (etylacetat?) and that it floculated a bit more.
Laust Ladefoged - 2020-08-09 14:54:24
For info on yeast in Denmark, I think you should contact De Danske Gærfabrikker ( https://www.danskgaer.dk ) instead of Arla. They used to be part of De Danske Spritfrabrikker, which up until DK became part of EF in 1973, had a monopoly on producing yeast in DK. So I would expect them to have much longer records on yeast history in DK.
Lars Marius Garshol - 2020-08-10 13:51:22
@Karl: Yes, it might be, but the yeast for sweet dough is a new product, so I've always assumed it has a more recent origin. It's worth checking, though.
@Laust: That's very useful to know! Thank you.
Are Gulbrandsen - 2020-08-15 09:32:41
It seems baking with yeast was not common outside large cities in Norway until the end of the 19th century. I think this supports what you say about beer yeast. https://www.norgeshistorie.no/grunnlov-og-ny-union/1324-det-daglige-brod.html
Lars Marius Garshol - 2020-08-16 10:22:06
@Are: That's correct. In the cities people had to buy flour, and they bought wheat imported from abroad. Outside the cities people used their own grain, but Norway is so far north that people grew mostly barley (and oats on the coast). Barley and oats don't have enough gluten to make leavened bread from, so leavened bread was very rare in Norway.
People might buy some wheat flour and bake for Christmas. Leavened bread was called "kaku", and was considered a special treat. It's developed into the modern word "kake" (cake). Some places people say "kaku" or "kakskiv" when referring to leavened bread.
The traditional Norwegian bread was for millennia flatbread, and nothing else.
Joël - 2020-08-21 14:25:03
In the new book from Andreas Krennmair, « Vienna Lager », there is an interesting piece of information on how the relationship between brewers and bakers changed in the mid 19th century when brewers switched from ales to lagers: (p. 26) “Industrialisation had a profound effect on other breweries in and around Vienna : because of the quick success of Anton Dreher’s beer and brewing methods, all other breweries switched to bottom fermentation just within a few years. This rapid change had an unintended implication for another craft that had previously been reliant on breweries: baking. In the centuries before, bakers had been reliant on fresh beer yeast, which brewers always had available in abundance. When brewers started switching to bottom fermentation, the yeast given to bakers also changed its properties: (…) the yeast suddenly contained hop bittering compounds and hop resins that turned thee yeast darker and bitter-tasting, making it unsuitable for baking. (…) so the Viennese baker’s guild announced in 1845 that they would award a prize to the person who could produce a leaven that was suitable to replace the much sought-after top-fermenting beer yeast.”
Damjan Novak - 2021-05-20 00:10:30
Sry for the necro of this post, really fascinated by this theory!
Its a bit strange; the split between the B1 clade and the mixed Baker/Distiller M clade is necessarily older than the split of American ale and British ale within B1. Yet, the event associated with the latter is relatively old, related to the settlement of the Americas presumably, or at least the creation of significant American breweries, and the event splitting the yeast used by bakers and distillers from the brewers is presumably the very late moment of establishment of the “barm-brewers”, in late 18/early 19 century?
So you're suggesting that the mixed clade is actually what remains of some older european farmhouse brewing yeast group, and the “barm-brewers” ended up selecting for brewer's yeasts of such provinence by the harshess of the conditions to which they wanted to subject them? Soo the split of B1 and M is then around the time breweries become a big business and not just some extension of farmhouse practices?
Love it, a really exciting notion, thank you! Would love to know more about the diversity and history of commercial baker's and distiller's yeast sold in various countries today.
Lars Marius Garshol - 2021-05-23 20:20:38
@Damjan: The mixed group didn't necessarily split off when yeast production started. It could be an ancestral group of brewers yeasts like Beer 1 and 2, where some yeasts changed profession and started working for distillers and bakers.
It doesn't need to be a farmhouse yeast group. We see that Beer 1 contains farmhouse yeasts, so it could be the same with the Mixed group, that it contains both commercial beer yeasts and farmhouse yeasts. But, yes, I think the properties bakers wanted would tend to lead them to select farmhouse-like yeasts.
I think the origin of Beer 1 and 2 could lie much further back than Gallone et al estimated.
I too would love to know more about baker's and distiller's yeasts. I hope there are more studies on them coming.