B%, Flour, Water, Yeast, Salt – Bread & Bread machines

Table of Contents


Flour, whether refined and milled fine or coarse, is the ground product of grains. It contains plant proteins and starch. Starch is the carbohydrate in bread, and the ingredient thing that makes it food. Starch consisted of complex molecules of glucose and more complex sugars. The molecules react when exposed to water. Starch begins to dissolve which creates the condition when sugar in starch feeds yeast – fermentation. The proteins react to water by making dough sticky and stretchy.

White bread flour (and Canadian All-Purpose flour) and whole wheat flour milled from “red, hard” wheat are nearly standard commodities. There are variations depending on the wheat variety, and milling method. A recipe will describe the kind of flour, as well as the amount. The purposes of this kind of formula are to mix the right amounts of water, yeast and salt to get the right kind of bread,to predict how much dough to expect, and to organize the other steps of the baking process. Recipes for the home baker usually list ingredients by volume – cups, tablespoons etc.  A recipe for a 1 lb. loaf of bread requires 2 cups of white bread flour or whole wheat flour.  By the early 20th century, most recipes referred to a standard measuring cup, which could vary depending on where the recipe was published:

  • A US cup is .87 of an Imperial (U.K., many other English speaking countries) cup. An Imperial cup is 1.2 US cups;
  • A metric cup is a quarter liter (250 millilitres) which is .88 Imperial cups or 1.06 US cups.

The method of filling the measuring cup affects the density and the weight of one cup. When a measuring cup is put into flour and used to scoop the flour, the flour is more dense. When flour is scooped with a scoop and or spooned into a measuring cup, it is less dense. There is a range of weights for a USA cup of (white) bread flour in the sources:

  • 4.25 oz. = 121 g. See: King Arthur Flour ingredient weight chart. King Arthur Flour’s method is to use a scoop, “fluff and sprinkle” and level the top of the measuring cup.;
  • 4.5 oz. = 128 g. Peter Reinhart (The Bread Baker’s Apprentice, and other books) says 4.5 oz.; he measures flour scooped in a scoop and poured into the measuring cup;
  • 4.875 (i.e. 4 and 7/8) oz. = 138 g.;
  • 4.9 oz. = 139 g.;
  • 5 oz. = 141 g. The Bread Lover’s Bread Machine Cookbook (BLBMC) suggests 1 cup of bread flour or whole wheat flour converts at 5 oz. 

Whole wheat flour ranges from 4 oz. = 113 g. (King Arthur) to nearly 5 oz. per cup (BLBMC). While whole wheat and bread flour weigh nearly the same amount per unit of volume, bread flour has more of the proteins that bond to form gluten. It is mixed, kneaded and handled differently.

Many recipes round flour and water to the nearest quarter cup. The Bread Lover’s Bread Machine Cookbook (Harvard Common Press, 2000; by Beth Hensperger) goes to the nearest 1/8 cup. 

Measuring by weight is the standard for commercial baking. Scales in ounces go down to 1/8 oz, but not necessarily to decimal fractions.  Metric kitchen scales go to the nearest gram. That is close enough for flour. Converting a recipe involves interpreting the recipe and making assumptions about the writer measured ingredients, and assumptions about ingredients. Errors in conversion and mistakes in arithmetic (e.g. slips in entering numbers in a calculator) can change the dough and the loaf. A recipe may list flour by weight, or a book may discuss conversion. Where recipes provide weight, I refer to weight. If not, I guess and experiment. In recipe conversion usually drag-scooped cups are more appropriate.

For bread machine bread, I weigh (white) bread flour (Canadian All Purpose) and whole wheat flour at 139 g. per cup in a recipe.

Zorjirushi bread machine manuals recommend scooping and filling measuring cups or weighing. The Zojirushi recipes imply:

IngredientVolumeWeight1 cup =
Bread Flour4 ¼ cups544 g.128 g.
Whole wheat flour4 ¾ cups570 g.120 g.

B% (Bakers’ formula, or bakers’ ratio

Baker percentage (B%), a method of managing the production of bread. It is explained in a some baker cookbooks, For instance Peter Reinhardt devotes pages 40-45 of The Bread Baker’s Apprentice to this topic. It is a tool taught to professional bakers, and addressed in texts such as Daniel T. DiMuzio’s Bread Baking; An Artisan’s Perspective. For the baker-manager, it is a calculation to scale inputs to create 2, 10, 100 or 1,000 consistent loaves of bread. The assumptions are consistency of ingredients, equipment, energy, working space, and time.  For managing production, every ingredient is put into the formula.  It is as precise as it needs to be, for how it is used. B% is explained:

B% is a list of ingredients by weight, for a batch of dough – an instruction to make baking consistent and get the same result every time. . The professional baker will have to mix enough dough to bake dozens or hundreds of loaves, divide it, shape it and bake it. The essential ingredients – flour, water, yeast and salt – need to be measured, mixed, fermented and baked the same way. The home baker uses less ingredients and will only make a few loaves in one session.

The simplest version of the formula or ratio starts with the weight of the four essential ingredients. The weight of flour is treat as 100%, The weight of salt and yeast are noted and calculated as a percentage of flour weight. Water is weighed and is also calculated as a percentage of flour weight – the percentage is called hydration.

A couple of simple recipes follow. The first is a dough for 2 batard loaves of French bread. The second is for 2 pounds of bread, followed by dough for several loaves of ciabbata or baguette

WeightPercentwhatBy volume,
White Flour580 g.100flour weight4 cups
Water406 g.70hydration1 ¾ cups
Instant Yeast4 g..71 ½ tsp.
Salt12 g.22 tsp.
Total172.7percentage total
Emily Buehler, Bread Science, Location 2878
CiabbataCiabatta %Baguette
Baguette %
Bread Flour1377 g.1002156 g.100
Water1060 g.771488 g.69
Instant Yeast10 g..712 g..6
Salt28 g.254 g.2.5
Daniel DiMusio, Bread Baking

When one type of flour is used, the flour weight is the total flour weight.

When different flours are combined, the weights are added to determine total flour weight, even when flours differ in density and protein content. The relative amounts of flour are identified as a percentage of the total flour weight (e.g. 50% bread flour and 50% whole wheat; or 90% bread flour and 10% rye flour). It gets complicated. While any dry ingredient can be weighed and a B% calculated, not all dry ingredients count for Total Flour. The total flour weight can be the sum of the weights of:

  • flour, including any grain product such as rolled oats, grain meal or vital wheat gluten (gluten flour); or
  • all dry ingredients except salt, yeast, dry seeds, and fruit.

The weight of every ingredient can be listed and expressed as a percentage of the total flour weight. When the of flour, salt, yeast and water percentages are added up, the sum of percentages is well over 100%. A wet dough for a ciabatta bread will add up to 179%. This means the wet dough weighs 179% of the dry flour alone, at the beginning of the process.

I use mainly use metric weight; I may also note US ounces.

Nutrition Facts labels on bags of flour may suggest the weight of a quarter cup of flour. Online conversion calculators and tables also may appear to be useful. These are based on software that hook into the US Department of Agriculture (USDA) Data Cental tables or other data, which may use loosely filled cups, rather than drag-scooped cups. Other flours might graph to a mean, but show more variability. These numbers are high and can be reduced by a few grams per cup.

White Whole Wheat flour is mentioned in a recipe from BLBMC (p. 127) “White Whole Wheat Flour Bread”. (see variation with 3 cups of flour). It is supposed to work like bread flour; a loaf is supposed to work on basic bake, which is a “white bread” cycle. It is available from King Arthur mills in the USA:

White whole-wheat flour is … made with hard white spring or winter wheat — the bran, germ, and endosperm are all ground to result in another 100 percent whole-wheat flour. … because it’s made with hard white wheat instead of hard red wheat, like whole-wheat flour, it has a paler color and its taste is milder. It’s still nuttier than all-purpose flour because it includes the fibrous bran and germ of the wheat, but it’s a more approachable whole-wheat flour, particularly for those who don’t enjoy the hearty taste of whole-wheat flour.

It can be used interchangeably with whole-wheat flour in any recipe


I substituted Rogers “Whole Wheat Bread Flour”, for White Whole Wheat in a recipe. The Rogers product was an enhanced whole wheat flour, higher in protein (gluten) than the flour in the recipe. It was a lesson. I stopped looking for flour that can’t be obtained in this part of Canada.


Plain Water

In a simple recipe, there is just water. A cup depends on the recipe and the context. A cup of water,

  • USA standard, is 236.6 grams, which rounds up to 237 g. (in the metric system one milliliter of water is one gram).
  • An Imperial cup of water converts to 284 grams.
  • A metric cup of water is 250 grams.

Too much water is cited by many sources as a cause of some kinds of failure – weak and sunken loaves.  Too much is in relation to the amount of flour that is being hydrated, and the mixing or kneading action of the machine. An extra 30 grams (1/8 cup = 2 tbsp.) of water into 3 cups of flour means a wet sloppy dough.  The goal is tenacious and somewhat elastic (i.e. that pulls back to its original size and shape) dough that is also extensible – it relaxes.  T

Milk, Honey, Eggs, Syrups

A recipe may include milk, syrup, eggs, butter or vegetable oil. Wet ingredients, except oils extracted from pressed seeds, are water with sugar, fat and protein molecules suspended or dissolved in water. The water in a wet ingredient will interact with flour if it is not already bonded to something else. Any wet ingredient can be weighed and a B% calculated, but not all wet ingredients are counted as water. When a water-based fluid like milk is the only water in a dough, the weight of the milk is used to calculate hydration of the dough. Milk is nearly all water, but not all of the water is available to bond to the starch in flour – only 85 to 90%. 1 + 1/4 cups of skim milk has 1 + 3/16 cups (1 cup + 3 Tbsp.) of water. Some water remains bound to natural milk sugars including lactose and to milk fats. A cup of fluid cow’s milk weights 244-245 grams and contains about 12 g. of lactose and other milk sugars according to USDA averages. The sugars are hygroscopic but milk has ample water to hydrate the flour. Whole milk should be 3.25% butter fat. 2% milk, 1% milk, and non-fat (or skim) milk are reduced fat milk products.

Reconstituted milk (powder and fresh water) is nearly the same as milk. The ingredients on packages of milk powder and on the Web vary. The ratio of powder to water may be 4 or 5 Tablespoons to 1 cup. It depend on the brand and one use choices. Substituting powdered milk and water for fluid milk can be approached by mixing the powder and water and pouring the reconstituted milk into the measuring vessel, using the reconstituted milk in the amount in the recipe. In mixing the milk, 1 cup of water will gain weight but will only slightly change volume.

Unpasteurized milk can lead to surprizes. Some bakers think milk,  real or reconstituted, should be scalded to denature proteins. Mostly dry milk is produced by baking to dry out the water. The heat denatures the protein.

Butter, maple syrup, honey and other syrups have some water. The home baker’s trick is reduce water in a recipe by 1/4 cup for 1 cup of honey, when honey is used to replace sugar. The average for honey in the US and Canada is 17 g water per 100 g of honey. The typical pure maple syrup for sale in the US or Canada is 32 grams of water per 100 grams of syrup. A large egg, in the Canadian egg grading system, is about 57 g.  A large egg contributes 36 g. to hydration – nearly 3/16 of a cup of water.

For ingredients that are largely water – i.e. milk, butter, eggs, syrups – rather than seed or vegetable oil I note weight of water, taken from conversion tables.

Wet ingredients that contain water may be noted to see if a dough has a higher real hydration rate than a simple calculation implies. Ingredients that contain water are not necessarily counted directly in industrial B% – it involves conversions and extra math. Water content of baking ingredients can be calculated by referring the USDA Food Composition Databases. For a Canadian product, the Canadian Nutrient File may have the value. Using the databases takes some practice. Not all of the water reported in the data is released from the source ingredient and incorporated into dough. It may be necessary to use a teaspoon or two more water to get the hydration right.

I put in oil by volume and do not bother to weight it or calculate a ratio.

Yeast and Salt


Yeast means yeast organisms commercially grown, preserved, packaged, and distributed as a leavening agent. Most grocery stores carry active dry yeast and smaller grained dry yeast: instant yeast, quick-rise/rapid-rise yeasts, or “bread machine” yeast. Cakes and blocks of fresh yeast are rare, and not usually mentioned in home baking recipes. Recipes may refer to active dry yeast by volume (tablespoons and teaspoons); or by packets. Active dry yeast was and is still sold in foil packets containing .25 oz. of yeast. This was a tablespoon at one time. Active dry yeast became somewhat denser and finer grained. A packet of modern active dry yeast is about 2.25 teaspoons, but is still .25 oz. = 7 grams. A 7 gram/.25 oz. packet of modern active dry yeast is equivalent to 2 tsp. (6.2 grams) of instant yeast. Bread machine recipes refer to Instant yeast, bread machine yeast or active dry yeast. Conversion is simple if a recipe refers to instant yeast or to quick rise or “bread machine yeast. 1 tsp = 3.1 g. I tried to make conversions from active dry to instant yeast fast and simple with a table, which is in my post Dry Yeast.


Salt has several effects:

  • it alters or enhances the flavour of bread,
  • it preserves bread, for a few days, against some microbial infestation
  • it interacts with amino acids making up the gluten proteins, and affects the elasticity of dough. Less salt means a less elastic and tenacious dough.
  • it inhibits the yeast and slows the fermentation.

Thebakers’ rule of thumb is that when salt is decreased, yeast should also be decreased. This avoids an overinflated loaf that will collapse or overflow the baking pan, But the effects of salt on bread dough and baking are complicated.

Recipes that say “salt” always refer to ordinary table salt, unless a particular type or brand is stated. Some table salts are fine-grained and denser. Kosher salt has large crystals and it less dense. A baker measuring by volume should be aware of the differences, but crystal size do not affect measurement by weight. 1 tsp of ordinary table salt = 5.7 g. For quick reference in baking and bread machine baking, I read a refererence in a recipe as table salt, conventionally ground, and convert to weight:

Volume tsp. fractionVolume tsp. decimalWeight grams


For bread machine baking, yeast and salt should be measured to .1 gram, which requires a small high precision scale. This item is more expensive than measuring spoons, but important. Some brick and mortar retail stores sell high precision scales. There are several inexpensive scales available online.

Conversions, Volume and Weight

The King Arthur Flour ingredient weight table is good, but refers to ingredients as if all suppliers of a particular item have uniform standards and methods. I keep my data about baking ingredients in a spreadsheet on a local (i.e. where I am) device, rather than on a remote server on the Internet in the cloud.


3 responses to “B%, Flour, Water, Yeast, Salt – Bread & Bread machines”

  1. […] I checked conversions for my on Measuring and Conversion. […]

  2. […] recipe in the manual said 1.5 tsp of active dry yeast or 4.2 g. by weight I thought that the equivalent number was 3.6 g. instant dry […]

  3. […] Conversion factors are not always easy to find, and sources may disgree or only apply to some varieties of an ingredient, or to a brand of a commodity. I have made a list, found in the post Measuring & Conversion. […]

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