The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

question about differing yeast strains

pattyfermenty's picture

question about differing yeast strains

i have a question about the different yeasts that we use for our cultures, namely, are they really so different?

i have read that over time, the dominant yeast in a culture can change from one strain to another. i always create my culture simply by using KA flour (I never buy a culture) and that is the same flour i use to feed my culture. in other words, even if i created a camoldoli culture, for example, i am feeding it with flour that has a presumably different dominant yeast strain. with this in mind, i have two questions:

1. exactly how different ARE these cultures over time. can anyone say that without a doubt, over time, they have managed to keep two different strains and that those strains make noticeably and significant differences in the dough?

2. how different are the various strains in the various brand name flours that we use. are they all different, or do they all basically have the same strain of yeast.

Thanks in advance.

Nickisafoodie's picture

Starting on p 44 there is an extensive discussion on how cultures change based on the local environment in your kitchen, the natural yeast that is on the grain that the flour is milled from, the weather, etc.

He confirms with lab tests that after a matter of days a starter from half way around the world changes and becomes totally different.  And makes great bread and has great flavor.  And futile to expect otherwise.  And by the way, he also believes that the age of the starter correlated to making great or so so bread (from say 1852!) is more romantic than factual based.

If sour is the issue, you will also see much in this book about very liquid and watery starters that give a strong sour to German bakers, and all the way to thicker ones that are rather mild.  And of course length of fermentation.

In summary, there is no need to buy a starter unless you want to get one or two quick loaves from the culture before it naturally migrates to a different and natural flavor profile.  And tang is determined by variying degrees of hydration and fermentation time.  There is a lot posted in the archives on TFL, a search there will give additional perspective...


pattyfermenty's picture

Thanks for the reply.

So many people on internet message boards (along with the pizza boards) claim that they have multiple distinct cultures that they have maintained for a long time and that perform and taste differently.

When one thinks about it, there really is no reason that a culture's different yeasts should change over time unless the different strains reproduced at different intervals (some faster, some slower) or that some strains were more hardy than others (since food is the only limiting factor and it is always plentiful).

But in my experience, all my cultures smell, taste and perform the same, so maybe he is right. But what about those very old sourdough commercial cultures that they speak of like the SF sourdough -- if cultures are subject to change, how do they keep those cultures from changing significantly when they are feeding it with flour everyday that has, one would think, different yeast in it.

Fascinating stuff!



suave's picture

They are not necessarily wrong and neither is mr. Leader even though he has a knack for that. This is an extremely complicated question with too many competing factors in play to be certain of anything.

amolitor's picture

I've heard a lot about people maintaining different cultures with different flavors, but I've never run across anyone who claims that they feed two different cultures the same way, and still get two different flavors.

My take on this is that your rye starter tastes different from your whole wheat starter because a) it has rye in it. not whole wheat, which a1) means that your bread has rye in it, not whole wheat and a2) the food supply for your ecosystem is different, so it's probably using different matabolic paths to different degrees, with different by-products and b) you're making different breads with it.

There might also be a different ecology going on in there, but really, there are SO MANY variables here you can't say one way or the other.

Ho Dough's picture
Ho Dough

worthy of mythbusters. The premise of all who sell least the dried kind.....are that they do in fact represent a different mix of yeast and bacteria that make that particular starter unique. That they will taste and behave differently. Likely as not, however, the keepers of the cultures are feeding each of them (exception might be whole rye or something), the same flours. Yet they continue to maintain they are different, remain different and perform different.

But some of these same folks also say it's possible to "capture" wild yeasts, suggesting the open air theory, vs. what is widely supported on this site, which is that yeast and bacteria spores ride in on the flour. More so on whole grains or organic whole grain flours, rye and wheat in particular. This has been proven time and again when successful cultures have been started while completly covered.

If the latter is the case, it stands to reason that new yeasts and bacteria would be introduced at each and every feeding. If we can do it when we are trying, what makes us think the same flours are not going to do it just because we no longer need them to? But with a yeast and bacterial culture already present, will the new guys get a toehold and thrive, or be snuffed? At least one reference I have suggests they are snuffed by the yeasts and bacteria of the resident culture. This seems to be the only plausible reason why a culture would remain stable.

But do we then have to consider the feeding schedule? A 1:1:1 schedule is common, but others also use 1:2:2 and even 1:5:5. The latter has a much lower starter to food ratio, which in thePh world, might allow bacteria and other invaders a chance to take hold, before the resident yeast and bacteria multiply enough to have an affect on the overall Ph of the culture. Same might be said for thick and thin starters. The ratio of starter to food source varying greatly.

I don't have any answers. Only questions. Lots of questions.