The French flour classification system, based on taux de cendres (ash content), is the foundation of French boulangerie’s precision and the key to understanding why French bread tastes different from bread made anywhere else. Unlike American and British systems that classify flour by protein content, the French system classifies by the mineral (ash) content remaining when a flour sample is incinerated at 900°C — this ash derives from the bran and germ, so the ash percentage directly indicates how much of the whole grain remains in the flour. The types: Type 45 (T45, ash 0.45-0.50%) is the whitest, most refined flour, used for viennoiserie and pâtisserie where a tender, fine crumb is desired; Type 55 (ash 0.50-0.60%) is the standard bread flour for baguettes and pain blanc; Type 65 (ash 0.62-0.75%) is the preferred flour for baguettes de tradition and pain de campagne, retaining more bran for flavour and colour; Type 80 (ash 0.75-0.90%) is a light wholemeal (bise) used for pain bis and pain de campagne; Type 110 (ash 1.00-1.20%) is a dark wholemeal; and Type 150 (ash >1.40%) is the full wholemeal (complète), containing the entire grain. The ash content correlates with several baking-relevant properties: higher ash = more mineral flavour, darker crumb colour, higher water absorption, more enzymatic activity, weaker gluten, and better keeping quality. The protein content (important for gluten) is a separate variable that French millers measure but do not use as the primary classification — a T65 flour typically has 11-12% protein, but this can vary between mills and wheat varieties. French bakers specify flour by Type number and may further specify protein content, falling number (indicating amylase activity), and W value (alveograph measurement of dough strength). Understanding the Type system allows the baker to make informed flour choices: T55 for white bread with neutral flavour, T65 for baguettes de tradition with more character, T80 for pain de campagne with rustic depth, and T150 for wholemeal with maximum flavour and nutrition.
Classification by ash content (mineral residue after incineration). Higher Type number = more bran = more flavour, colour, absorption, and keeping quality. T45 for pastry, T55 for white bread, T65 for tradition baguettes, T80 for campagne, T110/150 for wholemeal. Protein content is a separate variable. W value (alveograph) measures dough strength.
When converting French recipes for non-French flour: approximate T55 with a blend of bread flour and all-purpose flour; approximate T65 by adding 5% whole wheat to bread flour; approximate T80 with 80% bread flour + 20% whole wheat. The W value is the single most useful specification for bread flour: aim for W180-220 for baguettes, W250-300 for viennoiserie, W130-160 for biscuits and pastry.
Substituting American all-purpose flour directly for French T55 (different protein characteristics). Ignoring ash content when recreating French bread formulas. Using T45 for bread (too refined, too weak). Using T150 without adjusting hydration and mixing for the high bran content. Assuming higher protein always means better bread flour.
Le Goût du Pain (Raymond Calvel)