Thousands of years ago, honey was already called the food of the gods by the ancient Egyptians. But honey is not just honey. It owes its broad spectrum of color, taste, aroma and ingredients to the nectar collected by bees from various flowering plants and honeydew. In order to determine which plants the bees have visited for their honey or which nectar or honeydew they have collected, honey pollen analysis is an indispensable tool.

The honey pollen analysis is the third pillar, besides the sensory and the chemical-physical examination, to determine the geographical origin and varietal purity of a honey. Here the circumstance is used that each plant visited by a bee leaves its fingerprint in the honey in the form of a pollen typical for each plant species. Based on the number or composition of individual pollen, the geographical origin and varietal purity of the honey is inferred.

It is also used to help the beekeeper decide whether to declare the honey as varietal honey, because the honey jar must always contain the type of honey indicated on the label. A false declaration can lead to severe penalties by the food authorities.

How does the pollen get into the nectar or honey?

• Primary dusting: This is the pollen that is introduced into the honey by the bee in the course of nectar collection.
• Secondary pollen: Pollen that falls from the bee into the honeycomb cell through the hair coat or pollen pouches during honey processing.
• Tertiary dusting: pollen grains that enter the honey during centrifugation or, in the case of pressed honey, through bee bread.

By secondary, as well as tertiary dusting no conclusions can be drawn on the Trachtangebot.

The size of a pollen grain ranges from about 5 µm (5 thousandths of a millimeter) to 150 µm (Fig.1). There are about 5000 pollen grains in one gram of honey. However, not every plant leaves the same amount of pollen in the nectar. This depends on the inflorescence of the plant.

If the flower is upright, the pollen falls down into the nectar at the bottom of the flower when touched or blown by the wind and is thus picked up by the bee when collecting nectar (Fig. 2). If it hangs downwards (Fig. 3), most of the pollen falls onto the edge of the flower or out of the flower. This leaves little pollen in the nectar, which is brought into the hive by the bees. One speaks of over- or under-represented plants. This circumstance is taken into account when judging for botanical origin. (Bandion and Pechhacker, 2003 Method book for honey testing in Austria, ISBN 3-200-00072-4).

Basically, there are three different pollen donors:

• Nectar plants: plants that produce nectar and pollen (rape, sunflower, dandelion, etc.).
• Nectarless plants: plants that produce pollen only (plantain, corn, sour grasses, etc.)
• Wind-blooming plants: plants whose pollen is tolerated by the wind and thus gets into the nectar or honeydew (spruce, alder, birch, etc.)

Lime blossom honey from the Spargelfeldstraße site (harvest 2023): A full pollen analysis of the honey was carried out. All pollen forms were identified, listed and then 1,000 pollen grains were counted and listed according to frequency. Based on the results of this pollen analysis, the honey can be labelled as blossom honey or, more precisely, as "lime blossom honey".

A total of 44 different pollen forms were detected in our honey sample. The variety of pollen found makes the honey a typical honey from the north-eastern outskirts of Vienna: the bees collected both in the surrounding gardens and parks as well as in the fields of the Marchfeld. The honey therefore contains pollen from fruit trees, lilac, lime and robinia as well as buckwheat and strawberries from the surrounding fields. Various pollen from herbs from the fields and roadside verges complete the pollen spectrum. In keeping with the location address of Spargelfeldstraße, the pollen of garden asparagus is also found in our honey. Just like last year, according to our pollen expert Waltraud Auer, another pollen makes the honey special: "I mainly find pollen from the tree of heaven in Eastern Austrian honeys, which makes the honey typical of Vienna." The many different types of pollen identified make the honey something special.

The most common type of pollen (62.7 %) comes from the tree of heaven (Ailanthus altissima). Description: round pollen about 21-25 µm in size with a furrowed surface. Germination sites are formed as pore folds (see illustration).

Lime pollen (Tilia sp.), the pollen that gives honey its name, was detected with a significantly lower frequency of 5 %. Description: round pollen about 21-35 µm in size with a reticulated surface. Germination sites are formed as folds (see illustration).

But why can the honey be called linden honey despite this low proportion of linden pollen? In principle, the pollen is underrepresented in lime blossom honey - this means that although the honey consists of a high percentage of lime nectar, it contains only a few lime pollen grains. Due to this fact, lime blossom honeys may be labelled as varietal honey if they contain as little as 1 % lime pollen. Furthermore, there is currently no variety description for honey from the tree of heaven in the underlying assessment literature.

Blossom honey from the Spargelfeldstraße site (harvest 2022): We carried out a full analysis of the honey, so we identified and listed all pollen forms and then counted 1,000 pollen grains. We assessed the honey as "blossom honey": no pollen form is so abundant that the honey can be labelled as varietal honey. Although 49.5 % of the pollen grains found came from rapeseed, rapeseed honey must contain at least 60 % rapeseed pollen.

We found 39 different types of pollen in our honey sample. The variety of pollen found makes the honey a typical honey from the north-eastern outskirts of Vienna: the bees collected both in the surrounding gardens and parks as well as in the fields of the Marchfeld. Pollen from fruit trees and lilacs in the gardens, lime trees and robinias in the parks as well as rapeseed from the fields and many herbs from the fields and roadsides can therefore be found. According to our pollen expert Waltraud Auer, there is another pollen that makes honey special: "I mainly find pollen from the tree of heaven in eastern Austrian honeys, which makes the honey very typical of Vienna." But pollen from soya or trumpet tree is also rarely found in Austrian honeys - so our honey is a bit of a rarity.

The three most common forms of pollen come from rapeseed, tree of heaven and strawberry or cinquefoil (their pollen is indistinguishable in appearance):

Rape: Scientific name: Brassica sp.; frequency in the present honey: 49.5 %, size: about 30µm. Round pollen with a strongly structured net-like surface, germination sites are formed as folds

Tree of God: Scientific name: Ailanthus altissima ; frequency in the present honey: 5.6 %, size: approx. 30µm. Round pollen with a furrowed surface - like a strongly stretched net structure, germination sites are formed as pore folds

Strawberry or cinquefoil: Scientific name: Fragaria sp., Potentilla sp.; frequency in the present honey: 5.4 %, size: up to 25µm. Triangular pollen with a slightly furrowed surface (technical term: striato-reticulate), germination sites are formed as pore folds