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Minerals in honey, and what conductivity measures

The mineral fraction of honey is well under one per cent, contributes almost nothing nutritionally, and is one of the most useful numbers in the analytical panel — because it separates floral honey from honeydew without anyone tasting anything.

Honey scienceReviewed 2026-09-29

How much there is

Minerals are reported as ash — what remains when a sample is burned. A pale blossom honey typically leaves around 0.1 per cent; a dark honey or a honeydew honey can leave 0.5 to over 1 per cent. That is a fivefold to tenfold compositional difference, and it is the basis of a real analytical distinction. It is also, in absolute terms, a very small amount of mineral.

The mineral fraction, and what a teaspoon actually delivers
MineralShare of the ashIn a 7 g teaspoon of dark honey
PotassiumRoughly a third to a halfA few tens of milligrams
Calcium, magnesium, sodiumMost of the remainderSingle-digit milligrams
Iron, manganese, copper, zincTraceFractions of a milligram

Why conductivity is measured instead

Burning a sample to weigh its ash is slow. Dissolved mineral salts carry current, so measuring the electrical conductivity of a honey solution gives essentially the same information in minutes. Conductivity is reported in millisiemens per centimetre and is one of the few numbers that appears directly in the honey standards as a classification criterion rather than a quality one.

  • Below 0.8 mS/cm — blossom honey territory, and most pale monoflorals sit well under this.
  • Above 0.8 mS/cm — honeydew and chestnut honey, which the standards name explicitly as exceptions to the blossom limit.
  • Exempt from both limits in the EU — strawberry tree, bell heather, eucalyptus, lime, ling heather, manuka and tea tree honeys, blossom honeys whose conductivity can stray across the line.
  • The threshold is a classification tool, not a quality grade. Neither side of it is better honey.
Conductivity, pH, acidity and optical rotation in European honey types, lowest conductivity first
Honey typeElectrical conductivity (mS/cm)pH (pH)Free acidity (meq/kg)Specific rotation ([α]D20)
Rosmarinus (rosemary)0.15 ± 0.044 ± 0.211.5 ± 4.7-6.1 ± 2.8
Robinia (black locust, "acacia")0.16 ± 0.043.9 ± 0.111.2 ± 3.4-16.6 ± 3.1
Brassica (rape)0.19 ± 0.054.1 ± 0.210.3 ± 2.1—
Citrus0.19 ± 0.063.8 ± 0.314.3 ± 3.2-13.4 ± 2.4
Hedysarum (sulla)0.2 ± 0.05—27.2 ± 8-10.8 ± 2.7
Lavandula (lavender)0.21 ± 0.053.8 ± 0.117.3 ± 4-8.3 ± 3.8
Rhododendron (alpine rose)0.23 ± 0.063.9 ± 0.213.3 ± 3.3-5.8 ± 2.4
Phacelia0.23 ± 0.09—19.8 ± 7.5—
Helianthus (sunflower)0.34 ± 0.083.8 ± 0.223.1 ± 6.3-17.5 ± 1.9
Thymus (thyme)0.4 ± 0.073.8 ± 0.137.2 ± 6.3-20.1 ± 2.1
Eucalyptus0.48 ± 0.064 ± 0.219.4 ± 5.3-13.3 ± 2.3
Taraxacum (dandelion)0.51 ± 0.074.5 ± 0.210.9 ± 2-10 ± 2.1
Tilia (lime, linden)0.62 ± 0.124.4 ± 0.320.8 ± 7.7-12.5 ± 2.8
Erica arborea (tree heath)0.7 ± 0.09—34.7 ± 5-13.9 ± 1.6
Calluna (heather)0.73 ± 0.124.2 ± 0.232.1 ± 5.6—
Arbutus (strawberry tree)0.74 ± 0.1—35.1 ± 8.1-13.1 ± 1.9
Honeydew1.2 ± 0.225.1 ± 0.326 ± 5.613.9 ± 5.7
Castanea (chestnut)1.38 ± 0.275.3 ± 0.513 ± 3.5-16.7 ± 3.4
Metcalfa pruinosa honeydew1.69 ± 0.245 ± 0.337.2 ± 6.617.5 ± 6.5

Mean ± standard deviation across the samples in the International Honey Commission's European data bank (published 2004). A description of populations of honeys, not a specification for any jar; sample counts for each value are on the individual honey pages. Conductivity and specific rotation are on dry matter. The sign change in the last column — negative for blossom honeys, positive for honeydew — is one of the official ways the two are told apart.

Checked 2026-09-29 against: Main European unifloral honeys: descriptive sheets (Apidologie, 2004); Sensory analysis applied to honey: state of the art (Apidologie, 2004).

Read down the first column and the exemptions explain themselves. The pale blossom honeys cluster between 0.15 and 0.25 mS/cm. Lime, heather and strawberry tree honeys average between 0.6 and 0.75 — blossom honeys whose ordinary samples reach the 0.8 line — and that is exactly why the law lists them by name. Chestnut, honeydew and Metcalfa honeydew then sit well above it, with the Metcalfa honey averaging 1.69 mS/cm. The last column tells the same story from a different measurement: every blossom honey turns polarised light to the left, and both honeydew honeys turn it to the right.

Where the minerals come from

Nectar carries what the plant took from the soil, so soil chemistry, plant family and whether the sugar came from nectar or from honeydew all feed into the figure. Honeydew is the strongest single influence: aphid excretion has passed through both a plant's phloem and an insect's gut, and it carries far more mineral matter than nectar does.

The claims on this page

Every substantive claim is placed on a tier, and the top two tiers must also state what they are not claiming.

Commonly claimed, but not supported

Widely repeated and not supported by current evidence. Listed so the correction is here rather than only the claim.

Commonly claimed, but not supported

Dark honey is a meaningful dietary source of minerals.

Dark and honeydew honeys do contain several times the mineral content of pale blossom honey — a real, measurable difference used analytically to classify honey. But the total mineral fraction is under one per cent, so a teaspoon supplies a few tens of milligrams of potassium against a daily requirement of several thousand. A larger share of a very small amount is not a dietary source.

  • HoneyHQ editorial synthesis — HEKNO Ltd · HoneyHQ synthesis
  • Composition of American Honeys and related analytical work — United States Department of Agriculture · Peer-reviewed article

Sources

  • HoneyHQ editorial synthesis — HEKNO Ltd · HoneyHQ synthesis
  • Composition of American Honeys and related analytical work — United States Department of Agriculture · Peer-reviewed article
  • Standard for Honey (CXS 12-1981) — Codex Alimentarius Commission, FAO/WHO (1981) · Standards document Link
  • Council Directive 2001/110/EC relating to honey — Council of the European Union (2001) · Regulatory guidance Link
  • Main European unifloral honeys: descriptive sheets — Apidologie (2004) · Peer-reviewed article Link

How sources are selected and weighted is set out in the sources and evidence policy.

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