Honey Quality Vocabulary: Moisture, HMF, Diastase and Acidity

A page of numbers encourages people to search for pass and ignore the rest. Honey quality is not one result. Moisture concerns water content and stability; HMF changes with heat and storage; diastase is a natural enzyme activity affected by processing and time; and free acidity helps describe composition and condition. Each has a different unit and interpretation. Codex places moisture among essential requirements, while HMF, diastase and acidity appear in an annex intended for voluntary application by commercial partners. Read the section and scope before comparing values.

Codex sets a maximum moisture content of 20% for most honey, with a published 23% exception for heather honey. Higher moisture can affect stability, but a number should be interpreted with honey type, sample condition and method. A tissue test or observation of flow is not a substitute for representative sampling and an accepted instrument method. Open storage, poor closure or wet utensils can also change condition because honey attracts moisture. Check the percentage unit, measurement method, sampling date and the product category to which the limit was applied.

Hydroxymethylfurfural, or HMF, can increase with heating and storage. The Codex annex gives a general maximum of 40 mg/kg after processing or blending, and 80 mg/kg for honey of declared origin from countries or regions with tropical ambient temperatures and blends of those honeys. That exception shows why origin and context matter. HMF is not a precise clock for jar age and is not a complete adulteration test. It contributes to a larger assessment involving transport, storage, other indicators and laboratory method.

Diastase activity is measured in Schade units. The Codex annex states that activity after processing or blending is generally at least 8 Schade units, with a minimum of 3 for honeys with naturally low enzyme content. A lower figure is therefore not automatic proof of poor heating practice before honey type and the applicable exception are known; a high figure does not prove origin or purity either. Because activity changes with time and temperature, it should be read alongside HMF, sample date and storage history. A competent report also identifies the analytical method.

Honey naturally contains organic acids. Free acidity is a laboratory result expressed as milliequivalents of acid per 1,000 grams, not merely a tasting note. The Codex annex gives a value of no more than 50 milliequivalents per 1,000 grams. It can contribute to an assessment of condition, and the FSA lists it among honey testing characteristics, but it should not diagnose a cause or declare spoilage alone. Floral source, composition and storage matter. Do not confuse pH with free acidity: they are different measurements even though both concern acidity.

Start with the laboratory, accreditation scope, sample or lot identifier and testing dates. Read the method, unit and reference limit, then ask whether the limit is mandatory in the target market or part of a voluntary standard or contract specification. Do not crop away notes that may contain an exception, uncertainty or sample description. Avoid ranking different floral honeys on one value. A report is a traceability tool, not decoration. When a result supports a commercial statement, the statement should be no broader than the evidence.

A clear copy of the report, with only commercially sensitive details redacted, helps customers and researchers understand the laboratory, sample and result.