The following was updated on November 22nd, 2016.
Here’s an example of why I go out of my way not to mix honey from different hives.
The honey on the right was taken from one hive, and it tastes heathery. The honey on the left was taken from another hive, and it has a more earthy flavour. Both were harvested on the same day. The two hives are about 2 metres apart (7 feet), but the bees from each hive favoured different nectar sources, which resulted in slightly different honey from each hive. The favouring of specific pollen and nectar sources is called floral fidelity. The bees find an abundant nectar source and they stick with it instead of wasting time jumping from one type of flower to another. That’s why you’ll often see a flowering tree loaded down with honey bees while at the same time not a single bee goes anywhere near your beautiful Forget-Me-Nots. The results of floral fidelity are lost in most large beekeeping operations that have to blend all their honeys together. Not me.
NOVEMBER 22, 2016: I think it’s fair to say that honey bees (and all things in nature) are motivated by efficiency. It’s more efficient for a honey bee to learn how to get the nectar out of a single species of flower than multiple species of flowers. A honey bee’s brain, while densely packed with about one million neurons, is a tiny little speck of a thing around 0.5mm thick, and that speck can only hold so much information. It has to erase the old information to make room for any new information that’s coming in — and that slows everything down.
Judging from my observations, a honey bee knows how to:
1) Get to a specific location, the location of the flower. It leaves the hive entrance and literally makes a beeline towards the flower or the general location of the nectar source.
2) Extract nectar from the specific species of flower. The size and shape of each species of flower requires a different technique for holding onto the flower and reaching inside it to suck up the nectar (or collect pollen.)
3) Get back to the hive, specifically the hive entrance.
A change in any of those three greatly reduces the efficiency of the honey bee’s work. For instance, changing the location of the hive entrance by adding a rim beneath the inner cover (an inner cover with a top entrance) will move the top entrance up by only a few inches, but it’s enough to make most of the returning bees crawl all over the front of the hive looking for the entrance. Because the entrance is no longer in the exact spot it was before, each individual honey bee has to reprogram its little speck of a brain to learn the new location of the hive entrance. Sensing the disoriented bees, other foragers will often start scenting the location of the new hive entrance to save the returning, confused foragers from having to crawl blindly around the front of the hive looking for the entrance.
A change in the type of flower has a similar effect. The nectar isn’t located in exactly the same location on every species of flower. Flowers have evolved so that in order for the bees to get the nectar, they need to rub up against the pollen, so as to transfer pollen from one flower to the next. To the tiny speck of a honey bee’s brain, every flower is an entirely different puzzle they need to solve. And solving that puzzle slows down the bee. A new flower means the bee has to forget everything it knew about the old flower. That’s why the laws of efficiency compel the honey bee to stick to one type of flower, so all it has to do is repeat the same process over and over again, automatically and efficiently collecting nectar from a single species of flower all day long.
Hence, the magic of floral fidelity, and why bees will completely ignore one type of flower for another type of flower. (This is an extremely simplified explanation.) It also explains how varietal honeys are created, and why I don’t mix honey from different hives, or even different frames if I can help it. Too much is lost when everything is blended together.