Lets be honest there there can be a problem with ivy.
Just think about it a bit.
All the rest of their honey stores (mixed floral, most likely) is looted by the beekeeper. That leaves ivy, late in the season, as the majority of the stores (and also limited to them, by the beekeeper). That is not the natural situation (but may be for later swarms, or for well-founded colonies during a poor season). So their normal stores in a good or average year would be a mixture of honeys. and we all have heard that 'variety is the spice of life' (well, some of have).
Set against that, carbohydrate use, during the winter, is mostly used for conversion to thermal energy - heat. We (should) all know that impure sugar leads to dysentry - too much solids content which the bees cannot cope with. Whether that is simply the % protein (or other material) which causes it, I am not sure. Bees can easily cope with the normal approx 2% pollen content in honey.
So protein is a by-product or waste product, generally, during the winter. That means that all they actually need is carbohydrate. Winter bees have reserves of other winter nutrients deposited around their bodies.
I am like the NBK and do not raid my colonies for every scrap of honey. Even so, I intend leaving them with less than a full 14 x 12 brood box of stores this winter as I found the colonies were more than sufficiently stocked after the winter, this year, and I found myself removing frames of stores to make adequate space for early expansion. They will still have well in excess of a deep national box, but that is another issue (as to which may be best best).
So, in a nutshell, I would prefer to have a mixture of honies in the brood box, not just ivy; but whether or not it is a real problem is not really known definitely. I am not going to worry about it, one way or the other.
RAB
