Baker’s Percentages: A Primer

The below post brought to my attention that fact that not all my readers out there might know what baker’s percentages are, nor what a term like “hydration” means when talking about a bread dough. To answer the easiest part first, “hydration” simply refers to how much water a bread dough contains. As for the percentage, i.e., what a baker means when he/she says a dough has “70% hydration”, that has to do with a slightly odd but very easy system for describing proportions, known as “baker’s percentages”.

Clearly, when a baker says his dough has a hydration of 75%, it doesn’t mean that the dough is 75% water. That would be flour soup…or something akin to a crêpe batter. Rather, what the baker means is that for every measure of flour that’s gone into the dough, 75% of that weight has subsequently been added in water. So if a bread recipe calls for sixteen ounces of flour and has a hydration of 75%, you’d add 12 ounces of water. Simple. Far from being 75% water, the actual dough would be composed of just over 43% water.

It’s a strange sounding system, since it doesn’t really make any mathematical sense. It simply makes flour the yardstick by which all the other ingredients in the recipe are measured. A Jewish challah recipe, for example, is around 50% hydration, 25% eggs, 5% oil, 5% sugar, 1% salt and 1% yeast. What does it mean? It means for every pound of flour you’ll put in half a pound of water, a quarter pound of eggs, about an ounce and a half each of oil and sugar and so on. The total “percentage”, were you to add all those numbers up, is meaningless. 50% + 25% + 5% + 5% + 1% + 1% = 87%. Of what? Who knows? It’s not important.

The important thing is that baker’s percentages provide a simple language of measurement — one that transcends all others: metric, English, Swahili, you name it — by which bakers can scale recipes up or down infinitely. For the neat thing about baking is that the same set of proportions that works for a 2-loaf batch will work for a 20-loaf batch, a 200 or a 2000. In contrast to cooking, baking is a relatively precise science, one which very much appeals to an uptight personality like my own.

2 thoughts on “Baker’s Percentages: A Primer”

  1. Hi Joe, I have a question to ask you, but I don’t know where to post it, so I think here is fine.
    Currently i’m working with 45% hydration dough. i’ve been working with this recipe quite some time with no problem at all. one day i made a mistake of not adding the sugar into the dough preparation (just flour, water, yeast, and baking powder), and when i mix the dough instead of forming a ball, it ended up with individual clumps. i’ve tried to prolonged the mixing time but it makes no difference. i did the mistake twice in a row with same result, duh!
    then i realized that i forgot to put the sugar into the preparation. with the sugar added, the dough as usual, form a ball and ended up good. it’s….weird don’t ya think?
    my question, how does sugar affect the hydration and the forming of the dough? thanks

    1. Hey Danny!

      That is pretty wild indeed. Sugar is mostly there to feed the yeast, obviously, and I’m not aware of residual sugar having much effect on dough consistency. All I can think is that with that much water, the formula may rely on the sugar binding up some of the water so the gluten doesn’t get so widely dispersed that it can’t form a network. Sugar, as I’m sure you know, is hygroscopic, meaning it attracts and binds up water molecules. This may be the property that the dough needs to give it just a little more integrity, just enough to form a ball in the mixing step. But whether I’m right or not, it’s a fascinating problem.

      Thanks for the brain-teaser!

      – Joe

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