Is your honey within the Codex 50 meq/kg ceiling?

What is free acidity in honey, and why does Codex limit it to 50 meq/kg?

Free acidity measures the milliequivalents of titratable acid per kilogram of honey — predominantly gluconic acid produced when glucose oxidase (GOx) acts on glucose, plus minor amounts of acetic, lactic, formic, and citric acids. The Codex Alimentarius STAN 12-1981 ceiling of 50 meq/kg is set because higher values almost always indicate fermentation (yeast → ethanol → acetic acid) or prolonged warm storage. EU Directive 2001/110/EC adopts the same 50 meq/kg ceiling for table honey.

How do I run the AOAC 962.19 titration at home or in a small lab?

Dissolve 10.0 g of honey in 75 mL CO₂-free distilled water in a 250 mL beaker. Stir until fully dissolved. Titrate with standardised 0.1 N NaOH to either (a) a faint persistent pink with phenolphthalein indicator (pH ≈ 8.3, classical method) or (b) pH 8.50 with a calibrated pH meter (potentiometric, modern method). Record the volume of NaOH used to the nearest 0.05 mL. Plug volume, normality, and mass into this calculator. Run a blank (water + indicator only) and subtract its volume from your reading for high-precision work.

Why does the calculator subtract 0.5 meq/kg for the phenolphthalein endpoint?

Phenolphthalein turns pink at pH 8.3, but the true free-acidity endpoint that aligns with the Codex/AOAC definition is pH 8.50 (potentiometric). The phenolphthalein endpoint therefore arrives slightly early, and on average reads ~0.5 meq/kg higher than the potentiometric endpoint. Bogdanov (2009) Harmonised Methods of the European Honey Commission applies a 0.5 meq/kg correction so visual and electrode methods give comparable results. If you titrated with a calibrated pH meter to 8.50, switch the toggle to "potentiometric" and the correction is skipped.

My honey reads 55 meq/kg. Can I still sell it?

Not as table honey in EU or Codex-aligned markets. EU Directive 2001/110/EC offers a single legal escape route: re-label as "baker's honey" (industrial-use honey) up to 80 meq/kg, with the explicit statement "intended for cooking only" on the label. Above 80 meq/kg there is no legal table honey or baker's honey designation — the product is typically diverted to mead production, vinegar, or industrial fermentation feedstock. The U.S. has no statutory free-acidity limit, but FDA 21 CFR 102.5 prohibits misleading labelling, so honey with obvious fermentation flavour cannot be sold as "honey" without disclosure.

Which honey varieties naturally read high on free acidity?

Buckwheat (Fagopyrum esculentum) frequently tests 30–45 meq/kg even when fresh — its dark phenolic profile drives a higher baseline gluconic acid load. Chestnut (Castanea sativa) and manuka (Leptospermum scoparium) also run 25–40 meq/kg fresh. Light varieties — acacia, clover, orange blossom, tupelo, sage — typically stay under 20 meq/kg through their first year. A reading of 35 meq/kg in fresh acacia is a fermentation flag; the same reading in fresh buckwheat is unremarkable. Always interpret free acidity together with HMF (≤40 mg/kg) and moisture (≤18 %).

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