Let us look at how sugar affects yeast and subsequently bread. Why you should and why you should not use sugar.
Sugar is hygroscopic meaning that it attracts water. Salt is also hygroscopic.
Yeast needs water to be active.
We all know that salt slows down fermentation for this exact reason. It robs the yeast of water. Sugar does the same.
So, in short – sugar will not ‘feed’ the yeast. It will not speed up fermentation. It will only slow it down. You will see a significant decrease in yeast activity starting from around 10% sugar in the dough. But even 5% will slow it down as I demonstrate in the video.
To counteract the effect of sugar you should either let your dough rise for longer or use more yeast.
A good reason to use sugar would be for getting a more caramelised crust on your bread. Or to sweeten the dough.
The more sugar is used the lower the baking temperature should be to prevent the crust from getting too dark.
Yeast breaks down starch in flour into simple sugars to feed itself. It does not need your sugar.
So, forget what they told you. You do not have to add sugar to yeast to ‘feed’ it.
Watch the video here