The Fresh Loaf

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Rules for modifying yeast amounts

Bruce J's picture
Bruce J

Rules for modifying yeast amounts

I am new at baking bread by hand and I have to reduce the recipe amounts quite often.

I always work by weight and I reduce every item by the same percentage.  My specific question is about yeast.  I am not sure if you decrease yeast by the same percentage.  It seems that at times you might end up with too little yeast.  Does anyone have any rules of thumb about this?

OldWoodenSpoon's picture

a recipe by weight I do it purely by percentage, including the yeast quantity, but then I round the yeast result down to the nearest whole gram.  If I were going to scale one down (not a common practice for me) I would do it the same way, then adjust based on the results.  In general I use less yeast than formulas call for, at whatever scale.  For some reason, perhaps my well water, yeast goes crazy in my kitchen, and I don't need to use as much.  I learned that, though, by trying things and then adjusting.  The rule of thumb, then, would to bake at least once by a pure percentage conversion, and then adjust based on your experience.  It's called baking, I think. :)

Good luck!

PastryPaul's picture

We're in the same boat as OldWoodenSpoon, we often scale up but rarely scale down. The only difference is that I tend to round yeast weights up. When I do scale down, usually for a test, sometimes I get wierd weights for yeast, salt, or any other ingredients that are used in relatively small amounts. Sometime these weights are just impossible with the scales I have on hand. My smaller scales are accurate to a gram, and the larger ones to 5 grams. So if a calculation comes out to 1.28g instant yeast, I just go with 2g insant or, if I'm feeling particularly precise, 4 of fresh (which comes closer to the calculated requirement).

Using a little more or a little less yeast will not kill your recipe. The rising time will change, that's all.