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Where this comes from. The quantities are the National Bee Unit’s, from best practice guideline 7a on feeding sugar (November 2025) and the winter preparation fact sheet (June 2024). Where we have done arithmetic on top of their figures, we say so. Sources at the foot of the page.
The two mixes
There are only two, and the NBU gives them as quantities rather than as a ratio. That is deliberate and it is more useful, because it settles the old argument about whether “two to one” means by weight or by volume. 1
- Thick syrup, for autumn feeding: 1 kg of white granulated sugar dissolved in 630 ml of water. In old money, 2 lb of sugar to 1 pint. 2
- Thin syrup, for spring or an emergency: 1 kg of sugar in 1,260 ml of water. That is 2 lb to 2 pints.
Thick in autumn because the bees have to dry the water out of it before they can store it, and by September there is not much time or warmth left to do that in. Thin in spring because it acts more like a nectar flow and gets the colony building up.
What sugar
White granulated or caster. It makes no difference whether it came from cane or from beet. 1
Do not use brown or raw sugars. The NBU is direct about this: they will cause dysentery. The same goes for anything unrefined, molasses-based, or left over from baking. Icing sugar is not for feeding either, because of the anti-caking agent.
Buy the cheapest plain white sugar you can find in the biggest bag you can carry. There is no premium version of this that helps.
Making it
Do not boil it. Hot water dissolves sugar perfectly well, and boiling risks caramelising it, which bees should not eat.
- Weigh the sugar into a bucket or pan.
- Add the water hot, not boiling.
- Stir until it goes completely clear and pale straw coloured. If you can see grains at the bottom, it is not finished.
- Let it cool to about hand warm before it goes in a feeder.
Warm syrup is taken faster than cold. Do not put anything hot into a plastic feeder, and do not put hot syrup on a colony.
How much to make
Nobody publishes the arithmetic for this part. It is ours, worked out from the NBU quantities above, not a figure they print:
- 1 kg of sugar plus 630 ml of water makes roughly 1.25 litres of thick syrup.
- So a 6 litre feeder takes about 4.8 kg of sugar and 3 litres of water. In practice, a 5 kg bag of sugar and just over 3 litres of water fills it with a little left over.
- A 2 litre feeder takes about 1.6 kg of sugar and 1 litre of water.
- Thin syrup is looser, so 1 kg of sugar plus 1,260 ml of water makes roughly 1.9 litres.
The second useful number, again our arithmetic. Bees dry syrup down to about the moisture of honey before they cap it, so 1 kg of sugar ends up as roughly 1.2 kg of stores. If a colony is 10 kg short of the 20 kg it wants for winter, that is about 8 kg of sugar, not 10.
Autumn feeding: about 20 kg, and how to get there covers how to work out what a colony is short of in the first place. This page is only the mixing.
Making it in bulk, and keeping it
Syrup does not keep. Left standing in a feeder or a drum it grows mould, and the NBU flags that specifically as a reason not to leave it sitting on a hive. 2 Make what you are going to feed over the next week or so, and no more.
If you must hold some for a few days, keep it cool and covered, and look at it before you use it. Anything that has gone cloudy or ropey, or that smells of fermentation, goes down the drain, not into a hive.
Ready-made invert syrup in a box or a drum is the alternative, and it is a fair one. It costs more per kilo, it does not need making up, and it keeps until you open it. If you have a lot of colonies and no time in September, it is money well spent.
Two things not to feed
Honey of unknown origin. Never feed honey you did not produce. American foulbrood spores and EFB bacteria survive in it, and you cannot tell by looking. 1
The NBU goes further than most people expect and says to avoid feeding honey from your own colonies unless there is no history of disease in your apiaries. So your own supers are only safe if your own record is clean.
Syrup onto supers you intend to harvest. It ends up in the jar, and then it is not honey and cannot be sold as honey. Selling honey in the UK covers what that means.
Feeding it without causing a robbing war
Feed in the evening, after flying has stopped, and clean up any spill straight away. 2 Syrup smells like a nectar flow to every colony and wasp within range, and late summer is exactly when they are looking.
Reduce the entrance on anything weak before you feed it. Several of ours run underfloor entrances reduced with sponge, so that job is already done when the feeder goes on. Wasps at the hive: what actually works has the detail.
Setting up to feed is a separate job and has its own page.
When to stop
Depending on where you are and the weather, bees may be unable to process syrup and store it properly much beyond mid-October. 2 After that, syrup sits in the feeder, goes mouldy, and does no good.
From then on a light colony gets fondant instead, over the crown board hole or straight onto the top bars. Do not feed syrup in cold weather.
The short version
- Thick: 1 kg sugar to 630 ml water. Thin: 1 kg to 1,260 ml.
- White granulated only. Never brown, raw or icing sugar.
- Hot water, not boiling. Stir until clear.
- A 6 litre feeder is about 5 kg of sugar.
- 1 kg of sugar becomes about 1.2 kg of stores.
- Make it fresh, feed in the evening, and stop around mid-October.
This guide is general information, not legal advice. Rules change - always check the current guidance on GOV.UK before relying on it.