How I Calculate Nutrition

As I develop recipes, I often calculate the nutrition alongside the formula, baked weight and baker’s percentages. I’ve started sharing those figures on Culinary Exploration because they may be useful if you want a clearer idea of what’s in the bread you’re baking.

Not every recipe on the site has a nutrition panel yet. I’m working through them over time, and keeping the explanation here means the recipe pages themselves can stay focused on the bake. This page explains how I calculate the figures, what they can tell you, and what they can’t. I’d rather show my working than ask you to trust a number.

The short version

The figures are calculated estimates, not laboratory results. I build each recipe’s nutrition from its formula, the exact gram weights of every ingredient, matched against a single recognised food composition database, then expressed against the baked weight of the loaf. They’re a well-grounded guide, not a measured fact.

My data source

I use one database for every recipe on the site: McCance and Widdowson’s The Composition of Foods Integrated Dataset (CoFID), 2021 edition, the UK’s recognised food composition dataset, originally published by Public Health England and now maintained by the Food & Nutrition National Bioscience Research Infrastructure at the Quadram Institute.

Using a single source for everything matters more than which country it comes from. It means the numbers are calculated the same way across every recipe, so you can compare one loaf to another fairly. My readers are spread across the US, UK and Europe, and for energy, carbohydrate and fat, this usually makes little practical difference when the flour type is comparable. Protein and minerals vary more, but not usually enough to change the broad picture for a slice of bread.

Why I calculate against baked weight

A loaf weighs less out of the oven than the dough that went in, because water evaporates during baking. Nutrition is eaten per baked gram, so that’s what I calculate against.

For each recipe, I measure my own moisture loss, the percentage of weight lost in the bake, and state it on the recipe. This matters for you as a reader. If your loaf loses a different amount of water than mine, your per-gram values will differ. A drier bake concentrates the nutrition into fewer grams; a wetter one spreads it across more. The moisture loss shown on a recipe is the figure I used for that bake, not a universal constant.

Matching ingredients

Your ingredients won’t always match mine, and mine won’t always sit cleanly in the database. I handle this with one consistent rule:

I map each ingredient to the standard database entry a typical reader would most likely use, chosen by composition rather than by brand.

In practice, that means I match each flour to the closest standard database entry of the same type. A strong white bread flour is matched to strong white bread flour. A wholemeal flour is matched to a wholemeal flour. Rye is matched to rye.

So if I happen to bake with a specific brand of strong white bread flour, I don’t calculate the recipe around that exact brand. I use the standard strong white bread flour entry instead. If you bake the same recipe with another brand of strong white bread flour, the nutrition will be very close, because like-for-like flours are nutritionally similar.

Brand differences can slightly impact the numbers, especially for protein, but they typically do not alter the overall nutritional profile of the loaf. Calculating for the typical flour, rather than my exact one, means the figures reflect a normal bake rather than my specific kitchen.

How I handle salt

Food composition data reports sodium, not salt. To get the salt figure you see on labels, I add up the sodium naturally present in the ingredients, add the sodium contributed by the salt weighed into the dough, then multiply the total sodium by 2.5, which is the standard conversion from sodium to salt.

This captures both the salt I add and the small amount of sodium already in the flour and other ingredients. I don’t account for any salt added at the table or in serving.

A note on minerals

I show some minerals (iron, calcium, magnesium) separately from the core panel because they carry more uncertainty, and I’d rather show that honestly than imply a precision I can’t stand behind.

• They vary more. Mineral content depends on soil, growing conditions and milling, so database values span a wider range than the macronutrients.
• Fortification differs by country. The UK fortifies non-wholemeal wheat flour with calcium, iron, niacin and thiamin, while enriched flour in the US commonly includes iron and B vitamins. Practice elsewhere varies, so mineral figures are best read as typical values rather than exact values for your own flour.
• Content isn’t the same as absorption, and this is the part I find most interesting. Wholegrain flour contains phytate, a compound that binds minerals such as iron, magnesium and calcium and limits how much of them your body can absorb.
  Sourdough fermentation can break some of this phytate down, so the minerals in a long-fermented wholegrain loaf may be more absorbable than the same figures in an unfermented bread.
  How much depends on the flour and the length of fermentation, and the effect is smaller in white bread, which contains little phytate to begin with. A composition database measures what is present, not what is absorbed, so it cannot capture this. I keep the point deliberately qualitative: the direction is well supported, but the size of the effect is not something I would put a number on.
  
  

A note on units

Because my readers are global, I show energy in both kilocalories (kcal) and kilojoules (kJ), and I give the values per 100g of baked loaf as well as per 60g slice.

Per 100g is the universal anchor that lets anyone compare loaves regardless of where they are. The per-slice figure is based on a typical 60g slice, so you can judge your own slices against it: cut thicker or thinner and the values scale up or down accordingly. I anchor it to weight rather than a fixed number of slices per loaf, because slice counts vary too much from baker to baker to mean anything.

What these figures are not

They are not a substitute for laboratory analysis. If you need precise values for medical, allergen or dietary-management reasons, rely on lab-tested data or the verified information on your own ingredients’ packaging. My figures assume the recipe is followed as written. Changes to ingredients, quantities, portion size or bake will change the result.

In summary

I calculate from the full formula, against baked weight, using one consistent database, and I tell you my moisture loss and slice weight so you can judge how closely your bake matches mine. Where something is uncertain, I say so rather than rounding the doubt away.