Ingredients

How to Read a Flour Specification and Certificate of Analysis

By Robert Roessler, Food Scientist · Published 14 November 2026

Flour is the main ingredient of a bakery and the one that changes most from lot to lot. A specification and a certificate of analysis are the tools to keep it under control. This guide shows what they contain and how to use them.

1. Specification and certificate: two different documents

A flour specification tells you which characteristics and ranges you expect from the flour you buy. The certificate of analysis (COA) gives the test results for one specific lot. Think of the specification as the target and the COA as a snapshot of the flour that arrived (Baking Business). The American Society of Baking explains that a COA needs to be reconciled with the spec sheet every time, because using the wrong flour can mean dough that does not process correctly (American Society of Baking).

2. What a spec sheet should contain

According to the American Society of Baking, a flour spec sheet should define the requirements that the mill must meet to comply with the bakery's quality expectations, and setting it is the responsibility of both mill and bakery. It should include:

a sampling plan: how samples are taken and how often (for example per shipment or per mill run);
analytical specifications for quality parameters such as moisture, protein, ash and damaged starch;
microbiological specifications, for example coliforms, yeast, mold, E. coli and Salmonella;
the approved test methods;
the procedure when a test is out of specification.

(American Society of Baking)

3. The numbers on a COA

Parameter	What it tells you
Moisture	Water content of the flour. It affects storage, flour weight and yield.
Protein	Often the first number people look at. It matters, but protein alone does not tell you how the flour will perform; two flours with similar protein can behave differently (Baking Business).
Ash	Mineral content, linked to how much of the outer grain is in the flour. Higher ash means a darker, more wholemeal-like flour.
Falling Number	Measures alpha-amylase activity. The test shows how quickly a stirrer falls through a heated flour-and-water mixture; more enzyme thins the mixture and lowers the number (Baking Business).
Water absorption, damaged starch, farinograph values such as MTI	How much water the dough takes and how it tolerates mixing. The same source lists absorption, starch damage, Falling Number and MTI as results that may explain a change on the production line.

The Baking Industry Research Trust of New Zealand describes the falling number as a measure of enzymic activity and notes that a low falling number flour cannot be fixed; baking longer at a higher temperature helps only to a degree (BIRT flour testing information).

4. An example of a real specification

The U.S. Department of Agriculture publishes its purchase requirements for bakery flour. In the version of September 2023, bakers hard wheat flour (unbleached, intended for bread) is listed with protein from 10.5 to 12.0 %, ash from 0.50 to 0.56 %, moisture up to 14.0 % and a falling number between 250 and 350 (USDA Agricultural Marketing Service: Wheat Flour and Bakery Flour Products). The same document requires the supplier to keep the COA for at least seven years. These are the buyer's values for a federal purchasing program, not a law and not a recommendation for your bakery. Your own bread may need a different protein range. Use them as an example of how a specification looks, then agree your own with your mill.

5. How to use a COA in the bakery

Compare with the spec. Every number inside its range? If not, follow the out-of-specification rule you wrote.
Compare with earlier lots. The information is most useful when each COA is compared with the specification and with results from previous lots (Baking Business).
Note process changes. If dough starts handling differently, check the flour data next to your water adjustment, mixing time and dough handling.
File the COA with the delivery and with the lot number, so that you can trace a complaint back to a flour lot.

6. Questions to ask your mill or supplier

Which wheat types and which blend do you use, and how stable is it through the year?
Do you send a COA with each lot or on request?
What are your tolerances for protein, ash, moisture and falling number?
What microbiological tests do you run, and how often?
How do you handle allergen separation in the mill?
Which enzymes or additives are added, and are they on the label?

7. Connect it to your food safety plan

Incoming flour is a supplier-control point in a food safety system. Receiving checks, COA review and storage conditions belong in the plan described in HACCP for Small Bakeries. The nutrient values of common flours are listed in the ingredient database.

Summary

Write down what you expect from your flour, ask for a COA with every lot, compare it with the specification and the previous lots, and look at several numbers together instead of protein alone. File the COA with the delivery so that quality problems can be traced.

Sources

Information current as of 14 November 2026. Values from the USDA document are one buyer’s purchase requirements and serve as an example only. Agree your own specification with your mill.