Hi Everyone

I've come back here because I seem to remember there being some posters on this forum who are into their 'Detail' so maybe you can shed some light on this.

Over on the Dan Lepard's forum a breadbaker has asked the question of How Do Fats Work In Dough?

It's under the heading of Doughmaking on the main page and the poster is Zeb if anyone wants to have a look at her questions. Essentially she is asking if added fats inhibit yeast development in bread as some seem to think they do.

There are plenty of yeast loaves both wild yeast or the other kind that use fat in all sorts of forms and are successful. I myself use a little olive oil in my basic white breads, sourdoughs and dried yeast ones with no problems.

Just wondering if anyone on here would calculate a guess if in fact there may be reasons for fat to prevent yeast from performing?

Wouldn't the cooking process kill the yeast ?

Steve

Yeasts are unicellular fungi, and turn simple sugars into water and carbon dioxide. They need a supply of sugar solution to do this. Liquid fat (oils) may hinder this if they stick to the cell wall. As the cell wall is composed of virtually all carbohydrate, this is very unlikely. And even less likely if the sugar solution is made acidic, which is usually the case.

HTH

Thanks Lapis...I think I get it.

So are we saying the fat is slowing down the rate the yeast can develop ?

That being the case why not use less yeast or a short proving time ?

or is it to create a more uniform and less hollow spaced bread ?

More fats less large spacings but more dense and less risen breads ?

Steve

As per this website's bread making recipe ghee/oil is used. I always use oil whenever i bake.

Lapis

I've gone away and have thought about it but not sure if I understand right.

You're saying the fat in theory can hinder the process of yeast working if it sticks to its cell walls, because the yeast needs sugar (flour being carbohydrate providing that sugar) to feed on to work?

I think that's right?

So what you're saying is in theory it can but then in practice this doesn't really happen otherwise the recipes with fat in it wouldn't work and we know they do.

I'm then assuming the volume of fat to quantity of flour (carbohydrate)is so small it's not really going to effect the yeast?

what I am saying is what I said. For the yeast cell to do its thing, it must have a source of sugar solution. This is sugar, as in tea or coffee sugar, flour contains starch, which might break down (partly) to glucose when heated sufficiently or by enzymes in the body. We add sugar solution to the yeast to start the fermentation process.

If the cell wall was fat-liking (lipophilic) then oil/fat would stick to it, and that may hinder the yeast cell taking up the sugar solution. As the cell wall is mostly carbohydrate (though not starch or sugar) it would not attract oil/fat. So the notion that oil/fat hinders the yeast is unfounded by this reasoning.

yeast has to have a source of glucose to ferment, so that carbon dioxide is liberated, forming the bubbles in the dough/bread. It will not get this glucose from starch directly. You must have a starter fermentation to get the yeast going. If using dried yeast, sugar has to be in the dry mix with the flour. Unless there are other agents that convert starch to glucose, I cannot see how the yeast will work.

Lapis

"Unless there are other agents that convert starch to glucose, "

there must be because the dried yeast packets I use does not say it contains any form of sugar but say even if it does since the stuff is pre-packed and I can't be 100%, I can still go to my wild yeast loaves, my sourdoughs.

The sourdoughs leaven is made wild yeast originally and then you have this leaven which you feed on say a weekly basis with equal amounts of the leaven to equal amounts of water and bread flour.

If you don't feed your leaven it will eventually die because it has run out of its food source, the flour.

When you first feed the leaven it's at its best this means bubbling away like mad within 6-8 hours and after that the bubbling eventually dies down. So to make the bread you are best feed the leaven and leave it for 6-8hrs. The longer you leave your newly fed leaven the less likely you are going to have a successful outcome with your final loaf, though I have used leaven 2 and three days after feeding with ok results.

So as far as I can see with my sourdoughs I have no added sugars. mmm...interesting!