Acacia Honey (Black Locust)

Botanical Name: Black locust (Robinia pseudoacacia)

Botanical Family: Fabaceae

Bee Species:

The Western honey bee (Apis mellifera) makes the honey wherever it is sold. The nectar of a fresh flower sits behind a tripping mechanism that a honey bee is often too weak to work, so carpenter bees and bumble bees visit the fresh flowers on the first day, and the honey bees’ main collection begins only at full bloom and as the flowers start to wilt; from then a colony’s daily weight gain keeps rising for about eight days.

Slovenia’s protected Slovenski med, which lists acacia honey first among its types, may be made only by the Carniolan bee (Apis mellifera carnica).

Color:

Almost colourless to pale straw yellow, in some honeys with a faint green tint

Flavor Profile:

Sweet and mild, with weak acidity and no bitterness

Tasting Notes:

The taste is sweet and the finish short. The International Honey Commission gives its aftertaste as short, and Italy’s national sheet describes it as little persistent; the Lunigiana designation adds that it leaves no aftertaste. The body is liquid and clear.

What aroma there is comes most in the mouth. The Iberian reference guide for single-flower honeys finds floury notes best in retronasal smell, and Croatia’s Zagorje specification names vanilla, acacia flower, virgin comb and fresh butter. Vanilla recurs in the registered descriptions of Alsace, Varese, Lunigiana and Zagorje, and Italy’s sheet adds cooked pear.

Aroma:

Faint and floral: acacia blossom, vanilla, fresh wax and cooked pear

Defining Compounds:

Its sugars define it. In the International Honey Commission’s descriptive sheet, built from 715 samples, it holds 42.7 grams of fructose and 26.5 of glucose per 100 grams, a ratio of 1.61, and the sheet puts its liquidity down to that high fructose. European Union honey law allows it up to 10 grams of sucrose per 100 grams, where most honeys are held to 5. Laboratories recognise it by the pattern the sheet sets out: low electrical conductivity, colour, acidity, enzymes, proline and glucose, against high fructose and sucrose.

Two flavonoid markers come from the nectar, so a laboratory can confirm the tree without counting pollen. Kaempferol rhamnosides were found in every acacia honey analysed in a 2008 study and in none of the other floral honeys its authors had analysed, the first time such compounds were found in honey; acacetin was specific to robinia honey in a 2021 Romanian study that proposed it as a marker. China’s draft acacia honey standard of 2025 uses robinin, another compound from the tree, as a mark of authenticity.

Fraud has been caught with other tests. A 2020 study found mannose, never reported in acacia honey, in Chinese honeys sold as acacia that had passed pollen analysis, a sign of added syrup, and a Chinese study built a test for rapeseed honey, which its authors say is commonly passed off as acacia. In an enquiry published in 2019, France’s fraud authority found an acacia honey bought in Belgium with 13 percent cane or corn sugar added.

Forage Origin:

Black locust (Robinia pseudoacacia) is a fast-growing tree of the pea family, native to two separate areas of the eastern United States, the Appalachians and the Ozark-Ouachita uplands, and now planted or wild on every continent but Antarctica. It grows 10 to 35 metres tall and carries hanging clusters of white, strongly scented flowers between late April and June. Europe, China, Korea and Japan planted it for posts, vineyard stakes, fuel and mine timber, and to hold sand, spoil and eroding slopes; a 2017 review put its plantations outside the native range at more than 30,000 square kilometres in 35 countries, an area about the size of Belgium.

The tree gives much nectar and little pollen. Hungarian studies found that about three quarters of the nectar bees collect from it ends up as surplus honey. The flow is best on warm, humid, windless days above 25 degrees C after nights near 15; below 20 degrees good foraging cannot be expected, cold north winds stop the flow, and a late frost can end it before it starts.

Because the pollen is under-represented, a laboratory cannot expect a high pollen count in it. The International Honey Commission’s sheet gives a mean of 28 percent Robinia pollen, with limits of 7 and 60 percent, and standards set their floors low: 5 percent in the Hungarian Food Code’s guideline for quality-marked honey where the fructose to glucose ratio is at least 1.55, 7 in Russia’s standard and 30 in Bulgaria’s.

The name acacia is the tree’s own old name, not a relationship. Early botanists called it the American acacia and later the false acacia, the name the Codex Alimentarius and European Union honey law still use, and Bulgarian, Russian and Georgian call it white acacia. The true acacias of Africa, Arabia and South Asia (Acacia, Vachellia, Senegalia) are different trees. Honey locust (Gleditsia triacanthos) is a separate tree whose nectar seldom gives a surplus; pagoda tree honey (Styphnolobium japonicum) is sold apart from acacia honey in China; and gyalogakác (false indigo, Amorpha fruticosa) flowers with the black locust in Hungary and gives a honey of its own.

Honeys sold as acacia from other trees sit on some of the same shelves. In Tanzania and Kenya acacia honey comes from the savanna’s true acacias; in South Africa’s Northern Cape it most likely comes from swarthaak (black thorn, Senegalia mellifera); in Saudi Arabia the honeys sold under the Arabic names of two thorn trees, talh (طلح) and samr (سمر), come from Acacia gerrardii and A. tortilis, while talh in Sudan is Acacia seyal; Indonesian, Malaysian, Vietnamese and Brazilian acacia honey comes from plantation Acacia mangium, a fast-growing wattle, and its hybrids; in Pakistan producers sell the honey of two local thorn trees, phulai (پھلائی, Acacia modesta) and kikar (کیکر, A. nilotica), as acacia honey, and black locust honey there as robinia honey; Uruguay’s winter acacia honey is probably from Acacia longifolia, an Australian wattle; Argentina’s acacia negra names honey locust or Acacia melanoxylon, the Australian blackwood; the yellow acacia of the Altai and Kazakhstan is Caragana, the Siberian pea shrub; and Azerbaijan’s Hirkan acacia honey comes from the silk tree (Albizia julibrissin). An Omani study warned that buyers in the Middle East can confuse the two kinds and proposed naming each honey for its own tree.

Where the tree spreads, the law decides whether it can be planted again, and so how much acacia forage there will be. It is not on the European Union’s list of invasive species of Union concern, which a 2017 review attributes to the lack of a full risk assessment and to pressure from some member states, and it is not on the lists of the EPPO. Germany lists it for management and has required a permit to plant it in the open countryside since 2020; Hungary’s Constitutional Court in 2024 struck down an emergency rule that let acacia regrow in protected forests; Japan’s 2026 alien species list names it an industrially important species to be managed, with no substitute yet for beekeeping; Minnesota has listed it as a restricted noxious weed since 2017; South Africa lists it in category 1b; and Ukraine banned it from forest regeneration for about five months in 2023.

Pairings:

Sources give its mildness as the reason to use it. Italy’s honey observatory names it the most suitable honey for sweetening drinks, yoghurt and fruit without changing their taste, and producers from Bulgaria to Hungary put it in tea, on bread and butter and on yoghurt.

With cheese, an Italian producer offers it with fresh goat’s- or cow’s-milk ricotta. For blue cheese, Piedmont’s beekeepers’ association pairs it with gorgonzola, while a Hungarian training book finds that Roquefort drowns it. An Italian pairing table adds pecorino piccante and primo sale.

As an ingredient it goes where only a light honey flavour is wanted: gelato, fruit salad and panna cotta, a honeycomb tart with ricotta and lemon in recipes published by Korea’s Rural Development Administration, and, a Hungarian forestry journal wrote in 1917, fine honey wine, for which pure acacia honey was the best.

Health Uses:

In Russian folk medicine acacia honey, diluted in warm water, was used as eye drops and for the stomach, Russia’s beekeeping journal records.