When to harvest honey: capped cells, water content and timing

Taking honey too early gives you a jar that ferments on the shelf. Taking it too late can mean honey that has set hard in the comb, a missed varroa treatment, or a colony that heads into autumn short of food. The good news is that the bees tell you when honey is ready, and a couple of simple checks confirm it. Here is how to read a frame, what water content means, and how to time the harvest in the season.

Capped cells: the bees' own signal

Nectar arrives in the hive thin, often more than half water. The bees fan it and pass it between them until its water content falls to around seventeen or eighteen per cent, and then they seal each cell with a wax capping. Capped honey is ripe honey.

The working rule is that a frame is ready when around eighty to ninety per cent of its cells are capped. A super rarely ripens evenly, with the middle frames finished before the outer ones, so check frame by frame. For a frame with some open cells, hold it flat over the hive and give it a sharp downward shake. If drops of nectar rain out, those cells are not ripe; if nothing comes out, the uncapped honey is close enough to be taken with the rest.

Water content and the refractometer

Honey keeps because it is too concentrated for yeasts to grow in. Above about eighteen per cent water the risk of fermentation rises, and above twenty per cent, the upper limit food standards commonly allow for most honey, it is likely. Honey that ferments tastes sour, foams and can push the lids off the jars.

A honey refractometer measures water content from a single drop in a few seconds. It is the one instrument worth buying before selling honey, especially in a humid climate, where even capped honey can be on the wet side. Calibrate it as the maker describes, test a few frames from each super, and set aside any batch that reads high; it can be fed back to the bees or used first at home.

When in the season

Most beekeepers harvest at the end of each main flow rather than on a fixed date. In temperate northern climates that often means a midsummer harvest after the spring and early-summer flows, and a second in late summer, roughly June to August; in the southern hemisphere the same pattern falls between December and March. Two crops need watching more closely. Honey from oilseed rape, canola, and some other plants crystallises quickly and can set solid in the comb within days of being capped, so it should come off as soon as it is ready. Late honeys, such as heather or ivy, come after the main harvest and may be better left as winter stores.

The last supers of the season have to come off in time for two things: the late-summer varroa treatment, most of which cannot be used with supers on, and the colony's own winter stores. Why the late-summer treatment matters explains why that deadline is worth keeping.

Taking the supers off

• Clearer boards with one-way bee escapes go under the supers a day or two before the harvest; the bees go down and cannot get back up. Do not leave them on much longer, or wax moth and robbers find the unguarded honey.
• Fume boards, pads with a bee-repelling scent, clear a super in minutes on a warm day and suit larger apiaries.
• Shaking and brushing frames one at a time works for a hive or two, gently and without smoke blown across open honey, which can taint it.

Whatever the method, get the supers indoors and covered quickly: a stack of honey left in the open starts robbing within minutes.

What not to take

• The honey in the brood box. It is the colony's larder, and in most climates it is the start of the winter stores.
• Frames that held brood or much pollen. They taste different and belong in the brood nest.
• Anything filled while the colony was fed syrup. It is sugar, not honey.
• Supers that were on during a treatment not approved for use with supers, and anything inside a withdrawal period on a treatment label.

Weigh it, hive by hive

Before the supers go to the extractor, weigh them and note which hive they came from. It takes a few minutes, and it is the only way to find out which colonies actually produce, which is worth more than the total. Why weight per hive beats the truck total explains what to do with the numbers, how to extract honey covers the next step, and the harvest records in BeehiveMind take each weight against the hive or the apiary it came from.