Minerals in honey, and what conductivity measures

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.

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.
• The threshold is a classification tool, not a quality grade. Neither side of it is better honey.

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.