Sugar syrup for bees: work out sugar, water and acetic acid
Enter how many kg of sugar you want to mix, choose the strength, and see how much water and acetic acid you need.
Water = sugar × (1 − p) / p, where p is the sugar percentage. The syrup takes up about the water plus 0.625 litres per kg of sugar. Acetic acid: 1 dl of 32 % acetic acid per 25 kg of sugar, which is 4 ml per kg. These are the same formulas Danish beekeeping associations use.
Which strength should the syrup be?
- 40 to 50 percent (1:1) is stimulative feed. Use it in spring and for nucs, where it imitates a nectar flow and gets the queen laying.
- 60 percent (3:2, that is 3 kg of sugar to 2 litres of water) is the usual winter feed. It is thick enough for the bees to dry down and cap quickly.
- 67 percent is very thick and hard to dissolve without heat. Rarely used.
How to mix sugar syrup
- Use a clean bucket or pan. Pour in the water. Warm water makes the sugar dissolve more easily, but it must not boil, as caramelised sugar is toxic to bees.
- Add the sugar a little at a time and stir until it has fully dissolved. At 60 percent the water needs to be warm.
- Add the acetic acid last and stir well. The acid lowers the pH, prevents mould and helps the bees turn the sugar into glucose and fructose.
- Let the syrup cool to lukewarm and give it in the evening in a tray or bucket feeder.
How much do you need?
A colony needs 15 to 20 kg of sugar for winter. Mixing 60 percent syrup, 15 kg of sugar and 10 litres of water make about 19 litres of syrup, given in two or three portions in August and September. Use the winter feed calculator to work out the total for all your colonies.
Winter feed calculator: sugar per colony ›
Frequently asked questions
What does 3:2 sugar syrup mean?
3 kg of sugar to 2 litres of water, which gives 60 percent sugar. It is the usual strength for winter feed.
Should I add acetic acid to the syrup?
It is common practice in Denmark: 1 dl of 32 percent acetic acid per 25 kg of sugar. It prevents mould and makes the feed easier for the bees to process. The syrup also works without it if you use it within a few days.
Can sugar syrup be boiled?
No. Above about 60 degrees the sugar starts to form HMF, which is toxic to bees. Use hot water, not boiling.