Author Topic: the different yeasts  (Read 817 times)

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Offline pizzamaking@seasalt.org

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the different yeasts
« on: July 26, 2010, 08:06:53 AM »
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.


Offline Bill/SFNM

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Re: the different yeasts
« Reply #1 on: July 26, 2010, 08:22:19 AM »
The topic of contamination of a strong, healthy culture has been debated many times here. I maintain 5 cultures all with noticeably different flavor profiles and temperature responses. Take a look at reply number 12 in this thread which you might find applies to your first question:

http://www.pizzamaking.com/forum/index.php/topic,10188.msg92083.html#msg92083

 

Offline pizzamaking@seasalt.org

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Re: the different yeasts
« Reply #2 on: July 26, 2010, 09:14:34 AM »
thanks for the link.

there is no reason why yeasts cannot coexist since the only limiting factor is food and there is food constantly supplied. flour used to feed itself introduces yeasts.

therefore, it seems to me that the issue is whether or not one of the strains reproduces faster than the others and at what rate. it seems very likely that our cultures are changing constantly, but at what pace is the question, and we cannot answer that without much more information than i have, that's for sure. as an aside, if one strain reproduces twice as fast as another, i could imagine it dominating very quickly.

so, what i have concluded is that at the end of the day, the best insight is the insight the you provided with your 5 different and maintably distinct cultures. your conclusion is what i would have guessed since so many talk about cultures maintained for years that have not changed in flavor.

perhaps it is the case that there is very little difference, if any, in the rate of reproduction among the types of yeast that find themselves in flour.

Offline Jackie Tran

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Re: the different yeasts
« Reply #3 on: July 26, 2010, 10:13:39 AM »
I too have successfully maintained 3 cultures, 2 of which I have grown myself.  All 3 are different and remain so in there individual characteristics in aroma, flavor, and leavening abilities.  I feed all 3 the same flour, bleached all purpose flour, however I only feed them about a tablespoon at a time for each feeding.   

I believe the risk of contamination from the flour used is very low.  Yeast in flour (in the absence of a strong existing culture) takes typically 5-7 days to culture.  An active starter will feed on the flour and multiple within 1-2 hours after feeding.  Any inactive yeast that is present in the flour doesn't really have a chance to take off and overtake the culture especially in such small amounts.

All 3 cultures have distinct aromas though they are very similar.  They differ in their alcoholic aroma, final taste, and leavening abilities.  At their most active state, all seem to peak at relatively different times after additional feedings.