Yeast

[fiftydollars]

Hello James,

Thank you for taking the time to answer my question(s). I am a big fan of baking and I bake pretty often. However, I feel that somehow I am not getting the right flavor and I am curious if the yeast I use could be the problem. I have used Fleischman and Red Star yeast and I have tried instant, active dry, fresh, etc. But I have really never gotten very familiar with their relative differences. The most common one I use Red Star active dry yeast and I use it because Costco sells it there in bulk so I don't have to buy tiny packets at the store. I store it in an airtight mason jar in the freezer (is this bad?).

What type of yeast do you use and why?

Do different types of yeast yield better results? Can you direct me to any sources or brands?

Am I barking up the wrong tree? Does yeast even make that big a difference? Should I be looking at the flour I use more closely (king arthur unbleached white or bread)?

Thank you very much,

Jorge

[James MacGuire]

First of all, let me say that yeast is, in the overall scheme of things, relatively inexpensive. I am wary of yeast bought in bulk ( where and in what condtions has it been kept?, etc) and I would certainly advise ( if they are indeed more reliable, don't be paranoid but do be somewhat wary of even these ) smaller, well-sealed packets, unless you bake often, and have "been around the block". Reliable yeast limits the variables, a good thing for neophytes, but for all of us the wiser investment. Why take the chance of making a bad batch of bread, especially if it is for pleasure? There was a superstition among traditional French bakers that too much bakers yeast "burns" the dough, in other words that the texture was destroyed. The explanation for this is much the same as that in the answer to the ascorbic acid query. Too much yeast hastens the physical evidence of fermentation- things begin to move pretty quickly, and seem ready for the oven- but the formation of the fatty organic acids which create flavor, texture, and keeping qualities require a longer fermentation. Bleached flours, " dough conditioners", and a good dose of yeast speed things up, but the baby is thrown-out with the bathwater.

Yeast manufacturers who sell yeast in the supermarket are in a delicate position : of course they want to sell yeast, but at the same time there is something noble about encouraging people to maintain ( more truly, these days, recreate) the tradition of home baking. And they cannot be blamed for assuming that people are increasingly in permanent "quick 'n easy" mode. Add to this the fact that large doses of yeast help sales, and there is no wonder why recipes provided in supermarket yeast packets call for lots of yeast, and minimum fermentation times. Yeast in this way becomes a sort of organic baking powder- that is, it is only there to blow things up. Too many bread "cookbooks" espouse this same quick and easy approach ( others, including a home bread guru or two, allow for longer fermentations, but so complicate things that they make little sense).

I prefer fresh bakers' yeast, but it is also what I am used to. My second choice would be instant dried yeast. Both must be well-stored, and properly used.

Remember, above all, that in good recipes, yeast should appear in relatively small amounts ( these are higher in sweet, rich doughs) , and it is not the flavor of yeast that you're after, but the flavor of fermentation The yeast only gets

things started. The flour and other ingredients must be chosen with care-- this will also limit the variables-- and above all, buy a book which makes sense, and begin with simple recipes.

As any true baker will tell you, there is nothing wrong with simple stuff.

I hope that Jeffrey Hamelman will find the time to add his comments. He really understands these things.

My best to you,

James

[Jeffrey]

Anyone who has been reading the postings on this forum knows very well that James has been answering the questions with lots of detail--years of hands on and head on work are the combination of skills he brings (along with the good humor), to the benefit of us all.

There's one aspect of yeast that he touches on that I will elaborate further on, because it's interesting. James mentions that doughs with a high sugar content (above about 12% of the flour weight) require more yeast. Why?

Yeast is a single celled fungus, and its cell walls are semi-permeable. Nutrients can flow in through the cell wall, waste products can flow out. That's simple enough. Simple too is the "hygroscopic" nature of sugar (and salt); that is, they attract moisture (hence a few grains of rice in the salt shaker in the summer or else the salt gets moist). One last piece of information is the yeast's need for moisture in order for it to metabolize and get on with its fermentation work.

Putting all these things together, in a high-sugar dough environment, the sugar is taking considerable water away from the yeast. This in turn slows down the yeast's ability to ferment the dough. Therefore, a higher percentage of yeast is required as the sugar content of a dough goes up. For example, it is not at all unusual to see brioche made with 5% or more yeast. It needs it. Were one to mix a dough that does not contain sugar, such as French bread, with 5% yeast, it would blow up in no time--loads of gas and no flavor.

Enjoy the bake,

Jeffrey

[project]

Four questions:

First, yes, sugar is hydroscopic, and that is the usual reason given for why high concentrations of sugar can act as a preservative where bacteria cannot grow.

In particular, we can believe that if a yeast dough has a lot of sugar, then the sugar can desiccate -- 'dry out' -- the yeast. So, it would seem that one solution would be to include not just more yeast but more water?

Second, for "Were one to mix a dough that does not contain sugar, such as French bread, with 5% yeast, it would blow up in no time--loads of gas and no flavor.", the "loads of gas" is clear enough by why "no flavor"?

Third, it is sometimes said that as dough rises, the yeast can become 'spent'. How can this be? I would guess that the yeast could continue to grow as long as there was a good balance of temperature, water, starch or sugar (as 'food'), and not too much accumulated alcohol or vinegar. So, for 'spent' yeast, what is going on?

Fourth, what is the difference between yeast and common bread mold?

[James MacGuire]

Project, I only saw your question as I was approaching thr keyboard ( with my usual trepidation) with something else in mind. I will ponder your questions, and secretly pray that Jeffrey answers them first.

Anyway, it struck me that since this Q+A has been going on ----to our great delight----- a good chunk longer than anticipated, I may as well keep throwing things in.

I think I mentioned in an answer to an earlier query that baker's yeast is a form of beer yeast. Someone , at some point ( and who thinks of these things, who invented puff pastry?) added the foam from a fermenting vat of beer to a bread dough( all beers in the old days were top fermenting, in other words, the yeast floated on top ) Saccharomyces Cervesiae exists on and around various grains: barley ( of course) but also wheat. This means that even though I have spent years building and maintaining sourdoughs, and feeling a somewhat fatherly ( motherly? why not) pride when I see the results of the extra work and care, I have to admit that baker's yeast is only one step removed from bakers, and just as fresh pasta made with egg is different from but not in every case better than dried pasta and that the two should be considered in separate categories, so should sourdough and yeast.

Someone wrote in the other day, and the gist of his opinion seemed to be that sourdough is the real stuff in terms of flavor, and the true challange to a real baker. Part of me wanted to stand up and cheer, but the other half hesitated, and I must say that if I were sentenced for some reason to working for the rest of my life with only one or the other, it would be a hard choice and in either case, I would forever be an unhappy guy. Sourdough loaves, especially when they are made with darker flours, pack a flavorful punch, and they can be lighter or denser yet remain satisfying, especially because most of us want to love them. On the other hand. if baker's yeast were that easy to work with, then there would be great baguettes and perfect croissants everywhere, when if fact, these are very difficult to find, even in Paris. Yeasted stuff is always evaluated with a cooler head....

The thing to remember is that the two are quite distinct, and that we should celebrate both. Recipes for "sourdough" which start things off with a packet of yeast will only yield polluted yeast. Sourdough is sourdough, and Sugihara, Kline and their colleagues found that sourdough loaves containing amounts of baker's yeast exceeding 0.2% by flour weight began to lose their defining characteristics ( the French government applies this in its definition of sourdough, as do manufacturers of active cultures). I love both types of fermentation to dabble in mixtures ( even the 0.2% yeast seems unnecessary) but those who wish to ( and I admit that there are interesting things to be done) should remember to keep the mother sourdough culture pure.

That's it for now, but I'll be around until the very end!

James