🍞 Mixing, Baker's Percentage and Formulation

Baker's percentage is one idea and one sum, and once you have it you can read any professional formula in the world.

The idea: flour is always 100 percent. Every other ingredient is expressed as a percentage of the total flour weight.

The sum: ingredient baker's percentage = (ingredient weight divided by total flour weight) times 100.

That is the entire system. Everything else in this module is that one line applied.

Work the published formula below and check every row yourself with a pen. This is a real printed formula, given in pounds, which does not matter at all because percentages have no units.

Flour 60.0 lb, water 37.2 lb, yeast 1.8 lb, salt 1.2 lb, sugar 2.4 lb, shortening 1.8 lb, defatted milk solids 1.2 lb. Total 105.6 lb.

1. Flour: 60.0 divided by 60.0, times 100 = 100.0 percent. The flour is always 100 by definition.
2. Water: 37.2 divided by 60.0 = 0.620, times 100 = 62.0 percent.
3. Yeast: 1.8 divided by 60.0 = 0.030, times 100 = 3.0 percent.
4. Salt: 1.2 divided by 60.0 = 0.020, times 100 = 2.0 percent.
5. Sugar: 2.4 divided by 60.0 = 0.040, times 100 = 4.0 percent.
6. Shortening: 1.8 divided by 60.0 = 0.030, times 100 = 3.0 percent.
7. Milk solids: 1.2 divided by 60.0 = 0.020, times 100 = 2.0 percent.

Add the percentages: 100.0 plus 62.0 plus 3.0 plus 2.0 plus 4.0 plus 3.0 plus 2.0 = 176.0 percent.

That total, 176.0, is the most important number on the card, and Lesson 2 shows you why. Call it T, the total formula percentage.

Now deal with the objection every learner raises. The percentages add to 176, and that is more than 100. Is that wrong? No. It is correct and expected. Baker's percentage is not a share of the whole. It is a ratio to the flour. If you want the ordinary percentage of the batch that water represents, that is a different sum: 37.2 divided by 105.6, times 100 = 35.2 percent. Both numbers are true. Only one of them is useful to a baker, and it is the 62.

Why the 62 is more useful is the whole reason the system exists. The stated chief benefit is that the baker can change the amount of any ingredient at any time without needing to refigure the percentages of all the other ingredients. Test that claim. Suppose you decide to raise the sugar from 4 percent to 8 percent. In baker's percentage you change one line: sugar becomes 8.0, and T becomes 180.0. Nothing else moves. In an ordinary recipe every percentage would have to be recalculated because the denominator changed. That is the practical difference between a recipe and a formula.

Now the two-flour rule, because many African bakeries blend. If a formula uses two or more flours, the flours together are 100 percent, and each is shown as its share of that 100.

Work it. A baker in Kumasi, Ghana, blends 40 kg of wheat flour with 10 kg of a second flour.

1. Total flour = 40 plus 10 = 50 kg. This is the 100 percent.
2. Wheat flour = 40 divided by 50, times 100 = 80.0 percent.
3. Second flour = 10 divided by 50, times 100 = 20.0 percent.
4. Check: 80.0 plus 20.0 = 100.0 percent. Correct.
5. Water at 62 percent = 50,000 g times 0.62 = 31,000 g. Note carefully that the water is calculated against the total 50 kg, not against the wheat flour alone.

That step 5 is where people go wrong. Every non-flour ingredient is a percentage of the combined flour weight.

One warning specific to composite flours. Cassava and wheat composite substitution limits for bread were not available for this course, from three separate research sources that could not be retrieved. This matters across West and Central Africa where composite flour policy is live and sometimes mandatory. The percentage arithmetic above works perfectly for any blend you choose. What this course cannot tell you is how much cassava flour your bread will tolerate, or what your government requires or permits. Obtain that from your national standards body and from the IITA or FAO high-quality cassava flour guidance, and establish your own limit by test bake.

Finally, note the equipment implication. Baker's percentage is unusable without an accurate scale. Cups and tins vary, flour compacts, and a scoop of flour today is not a scoop of flour tomorrow. A scale is not an accessory to this module. It is the module.

Lesson 1 gave you percentages. This lesson gives you the calculation you will use every single working day: you know how many units you need, and you need to know how much of everything to weigh.

The method has three steps and works for any formula.

1. Add all the baker's percentages together, including the flour's 100. Call the result T.
2. Flour needed = (target total dough weight divided by T) times 100.
3. Every other ingredient = flour needed times its baker's percentage divided by 100.

Work it fully with the published formula from Lesson 1, where T is 176.0. You want 20 loaves scaled at 900 g of dough each.

1. Target total dough = 20 times 900 = 18,000 g.
2. Flour = (18,000 divided by 176.0) times 100. First, 18,000 divided by 176.0 = 102.27. Times 100 = 10,227 g. Round to 10,230 g, because your scale is not going to resolve single grams on a ten kilogram weighing anyway.
3. Water at 62 percent = 10,230 times 0.62 = 6,343 g.
4. Yeast at 3 percent = 10,230 times 0.03 = 307 g.
5. Salt at 2 percent = 10,230 times 0.02 = 205 g.
6. Sugar at 4 percent = 10,230 times 0.04 = 409 g.
7. Shortening at 3 percent = 10,230 times 0.03 = 307 g.
8. Milk solids at 2 percent = 10,230 times 0.02 = 205 g.

Now check your work, because a formula card that has never been checked is a trap. Add every weight: 10,230 plus 6,343 plus 307 plus 205 plus 409 plus 307 plus 205 = 18,006 g. Your target was 18,000 g. The 6 g difference is rounding, and it is acceptable. If your check comes out more than about half a percent away from the target, you have made an arithmetic error, so find it before you mix.

That check is the habit that separates a formula card from a guess. Always sum the weights and compare with the target.

Now the correction that most small bakeries miss, and it costs them units every day. The 18,000 g in the calculation is scaled dough weight, meaning dough that actually reaches the scale. Fermentation and scaling losses reduce dough yield and can be up to 5 percent and more, depending on the work process. If you mix for 18,000 g and lose 5 percent, you have 17,100 g at the divider, which is 19 loaves at 900 g and a short piece, not 20.

So build the loss into the target before you scale. If your measured loss is L percent, then:

1. Adjusted target = required dough weight divided by (1 minus L as a decimal).
2. With an 18,000 g requirement and a 5 percent loss: 18,000 divided by 0.95 = 18,947 g.
3. Flour = (18,947 divided by 176.0) times 100 = 10,765 g.
4. Water = 10,765 times 0.62 = 6,674 g, and every other line is recalculated the same way.

Note the word measured. Five percent is the published figure for what fermentation and scaling losses can reach, not a benchmark you should adopt without checking. A published wastage allowance benchmark for small bakeries was not available for this course. Measure your own for one month, using the difference between the dough weight you mixed and the dough weight that actually reached the pans, and use that figure. A measured allowance beats a guessed one every time, and this is measurable in a week.

Now the card itself. A formula card is a document another person can execute without asking you a single question. It carries, at minimum, these lines.

1. Product name and the date the card was last changed.
2. Every ingredient, in the order it is added, with its baker's percentage.
3. T, the total, written at the bottom of the percentage column.
4. The form of the yeast, spelled out, because a card reading only yeast 2 percent is an incomplete card. Write instant dry yeast, or fresh yeast, or active dry yeast.
5. The scaling weight per unit and the number of units per batch.
6. Your measured loss allowance percentage.
7. Target dough temperature out of the mixer, from Lesson 5.
8. Mixing time and speeds for your own mixer.
9. Proof condition, described as a volume increase rather than only a time.
10. Oven setting and bake time as measured at your own deck, not as printed on the dial.

One last piece of arithmetic, to show what the card is worth. A baker in Mzuzu, Malawi, is asked for an order of 260 rolls scaled at 70 g of dough.

1. Required dough = 260 times 70 = 18,200 g.
2. Her measured loss is 4 percent, so adjusted target = 18,200 divided by 0.96 = 18,958 g.
3. Her T is 176.0, so flour = (18,958 divided by 176.0) times 100 = 10,772 g.
4. She weighs 10,772 g of flour and multiplies down the percentage column.

That took her ninety seconds and it will produce 260 rolls, not 247.

Hydration is simply the water expressed in baker's percentage. If your formula says water 62 percent, your dough is at 62 percent hydration. That single number does more to determine how a dough handles, how it bakes and how many units it yields than any other line on the card.

Start with the published bands by product class.

1. Lean bread dough: 60 to 75 percent water on flour.
2. Published white pan bread: 62 percent.
3. A straight-dough system needs 2 to 3 percent more water than sponge-and-dough.
4. Laminated pastry détrempe: 50 to 55 percent moisture.
5. Cookie and biscuit dough: 15 percent water in a published formula, though the flour's own absorption capacity in that formula is 50 to 54 percent.

Read point 5 carefully, because it teaches something important. A cookie dough is at 15 percent water not because the flour cannot take more, but because a short dough must not develop gluten and must spread rather than rise. Hydration is a product decision, not just a flour decision.

Here is the gap you must know about. Hydration bands for ciabatta, baguette and other high-hydration artisan breads were not available for this course from a technical source. Widely quoted figures exist in the trade, and they may well be right, but they were not verified, so this course prints none. If you want to bake those products, get the figure from a named baking text and then establish your own by test bake, because your flour's absorption governs anyway.

Which brings us to the link. Hydration is what you write on the card. Absorption is what the flour will actually take, defined as the water needed to reach a standard consistency of 500 Brabender Units on a farinograph. The published strength bands are: very strong flour above 63 percent, strong above 58 percent, medium strength 54 to 60 percent, weak below 55 percent. If you write 68 percent hydration onto a weak flour, the dough will be slack and unmanageable no matter how well you mix it. Your hydration must fit your flour, so it changes when your flour changes.

Now the money. Water is the cheapest ingredient you buy and it goes out of the door as sold weight. Work a real comparison for a baker in Tamale, Ghana, running 50 kg of flour per batch and scaling loaves at 800 g of dough.

At 62 percent hydration:

1. Water = 50,000 times 0.62 = 31,000 g.
2. Take the other ingredients from the Lesson 1 formula: yeast 3 percent = 1,500 g, salt 2 percent = 1,000 g, sugar 4 percent = 2,000 g, shortening 3 percent = 1,500 g, milk solids 2 percent = 1,000 g.
3. Total dough = 50,000 plus 31,000 plus 1,500 plus 1,000 plus 2,000 plus 1,500 plus 1,000 = 88,000 g.
4. Loaves = 88,000 divided by 800 = 110 loaves.

At 66 percent hydration, if her flour will take it:

1. Water = 50,000 times 0.66 = 33,000 g, which is 2,000 g more.
2. Total dough = 88,000 plus 2,000 = 90,000 g.
3. Loaves = 90,000 divided by 800 = 112.5, so 112 whole loaves.
4. That is 2 extra loaves per batch from water.

Before you celebrate, count the costs of that decision honestly. A wetter dough is harder to handle and to mould, it may need a different mixing approach, and the finished bread has a different crumb and a different weight after baking, because more of that water leaves in the oven. You must test bake and weigh the cooled loaf, not just count the pieces.

And here is a consequence almost nobody teaches, which is sourced and which matters enormously in a hot country. The dose of calcium propionate, the standard bread mould inhibitor, is published against hydration: 0.25 percent at 65 percent absorption, and 0.40 percent at 67 percent hydration in a straight-dough system. Read that again. A two point rise in hydration comes with a substantially higher published preservative dose. Wetter dough means more available water, and more available water means a friendlier home for mould.

Work what that costs the Tamale baker if she moves from 65 to 67 percent.

1. At 0.25 percent on 50 kg flour = 50,000 times 0.0025 = 125 g of calcium propionate.
2. At 0.40 percent = 50,000 times 0.0040 = 200 g.
3. The increase is 75 g per batch, which she must price at her own delivered cost.

And she must check one more thing before she uses either figure. Legal maximum preservative levels vary by country. The only maxima available for this course were European figures, and even those carried a citation error and are unverified. Never treat a dose from a technical source as a legal permission. Ask your national food authority for the maximum permitted level and for the labelling requirement before you sell.

So hydration is not a comfort setting. It sets your handling, your yield, your crumb, your preservative dose and your shelf life, and each of those is arithmetic you can do on the back of the card.

Mixing does three jobs at once: it distributes the ingredients evenly, it hydrates the flour, and it develops the gluten network that will hold the gas the yeast makes. Get any one of the three wrong and the loaf tells you.

The two main systems for bread are the straight dough and the sponge-and-dough, and the published comparison is precise.

1. Straight dough: everything mixed in one go, and the whole process runs about 3 to 4 hours from scaling through packaging.
2. Sponge-and-dough: part of the flour and water is fermented first, and the whole process runs 6 to 8 hours.
3. To use the straight dough system you need 1.0 to 1.5 percent more yeast and 2 to 3 percent more water than the sponge-and-dough version.
4. High-speed mixing in a horizontal mixer is published at 12 to 18 minutes.
5. A blended dough conditioner in a straight-dough system is dosed at 1.0 to 4.0 percent on flour.

Read that as a business choice rather than a craft preference. Straight dough puts more batches through one oven in a day and costs you extra yeast, extra water and a shorter fermentation, which means less flavour and a shorter shelf life. Sponge-and-dough gives you flavour and acidity, which in a hot climate also gives you protection against rope, and costs you half a working day of planning.

Work the yeast cost of that choice for a baker in Nairobi on 50 kg of flour.

1. Sponge-and-dough at 1.0 percent instant yeast = 50,000 times 0.01 = 500 g.
2. Straight dough at 1.0 to 1.5 percent more, so 2.0 to 2.5 percent = 1,000 to 1,250 g.
3. Extra yeast = 500 to 750 g per batch.
4. He prices that extra at his own delivered cost per kilogram, and compares it against the revenue of a second batch through the same oven on the same day. That comparison, not habit, decides the system.

Now gluten development, and here you must learn to read dough rather than a clock, because mixing times are specific to your mixer. The published 12 to 18 minutes is for a high-speed horizontal machine and tells you nothing about your own bowl. What you can do is judge the state of the dough: it moves from a rough shaggy mass, to a smooth cohesive one that begins to clear the sides of the bowl, to a state where a piece can be stretched out thin enough to see light through before it tears. Stop somewhere in that last stage.

Going past it costs you. Overmixing is listed as a possible cause of a poorly shaped loaf, a flat top with sharp corners, and moulder rejects. Undermixing appears as improper mixing across a long fault list, including lack of volume, open holes and coarse crumb, poor keeping quality and poor flavour. Notice that improper mixing appears under almost every fault, which is why mixing is diagnosed by elimination, and why the batch record from Module 1 is what actually lets you find it.

There is a second cost to long mixing, and it links to Lesson 5. Mixing puts mechanical energy into the dough as heat. Hand kneading adds only 1 to 3 degrees Celsius. A stand mixer adds 8 to 16 degrees Celsius. Every extra minute of mixing is also a decision about dough temperature, which is why the two lessons belong together.

Now improvers, because this is where a baker most often mis-doses through a units error. Ascorbic acid works by an oxidation mechanism: ascorbic acid oxidase naturally present in wheat flour converts ascorbic acid to its dehydro form in the presence of oxygen, and the oxidised form promotes disulphide cross-linking between gluten proteins. The result is better gas retention, greater elasticity, tolerance to over-proofing, higher water absorption and better oven spring. In other words, it is a mixing and gluten tool.

The published levels are given in parts per million on flour, which is the same as milligrams per kilogram. Convert them properly.

1. Typical usage is up to 150 ppm on flour. On 50 kg of flour: 150 mg per kg times 50 kg = 7,500 mg = 7.5 g.
2. The minimum effective level reported is 20 to 30 mg per kg of flour, which raised bread volume by 20 percent. On 50 kg: 20 times 50 = 1,000 mg = 1.0 g, up to 30 times 50 = 1,500 mg = 1.5 g.
3. Published maxima: 200 ppm under US FDA rules and 200 ppm in the EU and UK for all flour and bread except wholemeal, with the Codex maximum in wheat flour at 300 mg per kg.

Stop at point 3 and understand it. Those are foreign maxima quoted as examples of how such a rule is written. They are not your rule. Permitted improvers differ by country, and several countries ban treatment agents that Codex permits. Ask your national food authority which improvers are permitted where you trade, and ask your miller in writing which ones are already in the flour you buy, because if your flour is already treated you may be dosing twice.

Two more gaps to state plainly. Ascorbic acid overdose effects were not available for this course, and neither were DATEM and SSL usage levels or fungal alpha-amylase dosage. If you intend to blend your own improver, get a supplier technical data sheet from a named manufacturer and follow it. Do not scale a dose upward on the theory that if some is good, more is better. That theory has ruined many batches and this course cannot tell you where the ceiling is.

This is the lesson that turns a recipe into a process. Fermentation rate is set by dough temperature, so two bakers with the same formula and different dough temperatures get different bread. Controlling the desired dough temperature, or DDT, costs you nothing but a thermometer, and it is the single highest-value calculation in this course.

The problem is that mixing heats the dough. That heat is called the friction factor, and it is the temperature rise in degrees for your mixer, your batch size and your mixing time. Published values give you the shape of it: hand kneading adds 1 to 3 degrees Celsius, and a stand mixer adds 8 to 16 degrees Celsius. Both sources stress that the friction factor is unique to each baker, mixer and kitchen, and commercial spiral and planetary mixer friction factors specifically were not available for this course. So you must measure your own. Fortunately that takes exactly one batch.

The published formula is:

Friction factor = (final dough temperature times 3) minus (water temperature plus room temperature plus flour temperature).

Work it. A baker in Lusaka runs one test batch and measures everything with a probe thermometer.

1. Water temperature = 22 degrees Celsius.
2. Room temperature = 30 degrees.
3. Flour temperature = 28 degrees. Measure it in the bag; do not assume it equals the room.
4. Final dough temperature at the end of mixing = 31 degrees.
5. Friction factor = (31 times 3) minus (22 plus 30 plus 28) = 93 minus 80 = 13 degrees.

His mixer adds 13 degrees. That is now a permanent property of his bakery, valid for that mixer at that batch size and that mixing time, and he writes it on the wall.

Now reverse the formula to solve for the thing he can actually control, which is the water temperature.

Water temperature = (DDT times 3) minus (flour temperature plus room temperature plus friction factor).

Work it with his numbers, targeting 26 degrees, inside the 24 to 28 degree band published for best keeping quality.

1. DDT times 3 = 26 times 3 = 78.
2. Flour 28 plus room 30 plus friction factor 13 = 71.
3. Water temperature = 78 minus 71 = 7 degrees Celsius.

Seven degrees. That is the real lesson for a hot-climate bakery, and it is why so many African bakeries never hit a target dough temperature: they use water from the tap, which may be at 28 degrees, and their dough comes out at 33 and ferments in the fast band every day.

Work the published hot-climate example to confirm the pattern. Target DDT 25 degrees, flour 28, room 30, measured friction factor 8 for a small spiral mixer.

1. 25 times 3 = 75.
2. 28 plus 30 plus 8 = 66.
3. Water = 75 minus 66 = 9 degrees Celsius.

Again a chilled figure. You will need refrigerated water, or ice, or both, for most of the year. Budget for it as production equipment, because that is what it is.

With a preferment the arithmetic changes, because there is a fourth temperature in the mix. Multiply by 4 instead of 3 and include the preferment's own temperature:

Water temperature = (DDT times 4) minus (flour temperature plus room temperature plus preferment temperature plus friction factor).

Work it. Target DDT 25, flour 28, room 30, preferment straight from an overnight rest at 24, friction factor 8.

1. 25 times 4 = 100.
2. 28 plus 30 plus 24 plus 8 = 90.
3. Water = 100 minus 90 = 10 degrees Celsius.

The same rearrangement applies to measuring the friction factor with a preferment: multiply the measured final dough temperature by 4 and subtract all four of the other temperatures.

Now choose your DDT deliberately, because the published targets differ and each optimises something different.

1. 24 to 26 degrees Celsius, or 75 to 78 Fahrenheit, for best flavour and rise in wheat yeast breads.
2. 28 to 30 degrees, or 82 to 86 Fahrenheit, for a straight dough at the end of mixing in a fast commercial process.
3. 24 to 28 degrees, or 75 to 82 Fahrenheit, for best keeping quality.

A higher DDT gives a faster process and less flavour development and poorer keeping quality. Improper high dough temperature is a listed cause of poor keeping quality in the millers' troubleshooting guides. So decide what you are selling, write the target on the formula card, and hit it.

One honest limit. When your calculated water temperature falls below about 4 degrees Celsius, part of the water has to be replaced by ice, and the ice-substitution calculation was not available for this course. This course will not invent one, because getting it wrong means an under-hydrated dough. Obtain that calculation from a named baking text before you rely on it. What you can do safely today is chill your water in a refrigerator overnight, measure its temperature before you use it, and recalculate. And note the caution from Module 3: instant dry yeast should avoid direct contact with ice or ice-cold water, so add it to the flour rather than to the chilled water.

Most small bakeries start with a recipe somebody's mother used, written in cups and handfuls. That recipe may make excellent bread. It cannot be scaled, costed, taught to an employee or defended to an inspector. This lesson converts it, and the whole conversion is arithmetic you can do with a pen.

Step one is to stop measuring by volume. A cup of flour varies with how it was scooped, how the flour was stored and how humid the day is. Weigh everything, once, on a scale.

So make the recipe exactly as you always do, but weigh each ingredient into the bowl and write the grams down. Suppose a baker in Bamenda, Cameroon, does this and records: flour 520 g, water 330 g, salt 10 g, sugar 25 g, instant dry yeast 7 g, oil 20 g.

Step two is to convert to baker's percentage by dividing each by the flour weight and multiplying by 100.

1. Flour: 520 divided by 520, times 100 = 100.0 percent.
2. Water: 330 divided by 520 = 0.635, times 100 = 63.5 percent.
3. Salt: 10 divided by 520 = 0.0192, times 100 = 1.9 percent.
4. Sugar: 25 divided by 520 = 0.0481, times 100 = 4.8 percent.
5. Instant dry yeast: 7 divided by 520 = 0.0135, times 100 = 1.4 percent.
6. Oil: 20 divided by 520 = 0.0385, times 100 = 3.9 percent.
7. T = 100.0 plus 63.5 plus 1.9 plus 4.8 plus 1.4 plus 3.9 = 175.5 percent.

Step three is the audit, and this is where the conversion earns its money. Check each line against the published bands.

1. Water 63.5 percent sits inside the 60 to 75 percent lean-dough band. Keep it, subject to what her flour will absorb.
2. Salt 1.9 percent sits inside the 1.50 to 2.25 percent range and inside the 1.75 to 2.25 percent optimum. Keep it.
3. Sugar 4.8 percent is above the 3 to 3.5 percent fermentable solids the yeast needs and well below the 15 percent sweet-dough threshold. Keep it.
4. Instant dry yeast 1.4 percent sits inside the 0.5 to 2 percent lean-dough band, and because she has written the form down, the card can be handed to someone else.
5. Oil 3.9 percent sits inside the 2 to 5 percent bread band. Keep it.

Her grandmother's recipe is, as it happens, a sound professional formula. Many are. The point is that she now knows it is, and can prove it, and can change one line at a time without wrecking the rest.

Step four is scaling to production. She has an order for 40 loaves at 700 g of dough each.

1. Required dough = 40 times 700 = 28,000 g.
2. Flour = (28,000 divided by 175.5) times 100. First 28,000 divided by 175.5 = 159.5. Times 100 = 15,950 g.
3. Water = 15,950 times 0.635 = 10,128 g.
4. Salt = 15,950 times 0.019 = 303 g.
5. Sugar = 15,950 times 0.048 = 766 g.
6. Yeast = 15,950 times 0.014 = 223 g.
7. Oil = 15,950 times 0.039 = 622 g.
8. Check the sum: 15,950 plus 10,128 plus 303 plus 766 plus 223 plus 622 = 27,992 g against a target of 28,000 g. Rounding only. Correct.

Step five adds the losses, and there are two different ones, which people constantly confuse.

The first is fermentation and scaling loss, which can be up to 5 percent and more depending on the work process. This is dough that never reaches a pan. Correct for it before scaling: with a 4 percent measured loss, adjusted target = 28,000 divided by 0.96 = 29,167 g, and flour becomes (29,167 divided by 175.5) times 100 = 16,620 g.

The second is baking loss, which is the weight of dough pieces and bread lost during baking and cooling through evaporation of water and, in small quantity, alcohol. This is not waste. It is the reason a scaled dough piece always weighs more than the cooled loaf. Numeric baking-loss percentages by product type were not available for this course, and the source states plainly that these are not set values and fluctuate with several parameters. So measure your own. The formula is:

Baking loss percent = (scaled dough weight minus cooled loaf weight) divided by scaled dough weight, times 100.

Work it. She scales at 700 g and the cooled loaf weighs 630 g.

1. Difference = 700 minus 630 = 70 g.
2. 70 divided by 700 = 0.10.
3. Times 100 = 10 percent baking loss.

Now work backwards, which is the calculation that actually matters commercially. If she must sell a 700 g loaf, she cannot scale at 700 g.

1. Cooled weight = scaled weight times (1 minus baking loss).
2. So scaled weight = 700 divided by 0.90 = 778 g.
3. She scales at 778 g, and after a 10 percent baking loss the cooled loaf is 700 g.

Cool for 2 to 3 hours and do not slice or wrap above 35 degrees Celsius, because wrapping warm gives poor flavour and poor keeping quality and slicing warm makes the loaf cave in.

One last point, and it is a legal one. If your country regulates the declared weight of a loaf, this calculation stops being a costing exercise and becomes a compliance requirement, because the loaf must meet its declared weight after cooling, not before. Whether such a rule exists where you trade, and what tolerance it allows, is set by your national authority. Ask them before you print a weight on a wrapper.