No. White granulated sugar and water only. Brown sugar is one of the few things people offer bees that can actively harm them.
Brown sugar contains molasses. The molasses is the problem, not the colour. The same applies to demerara, muscovado, coconut sugar, anything sold as raw, unrefined or organic cane sugar, plus golden syrup, treacle, maple syrup, agave and every artificial sweetener.
* Important * Never use honey when feeding a tired bee. Honey you buy from supermarkets and shops can carry spores that spread disease between colonies.
If you’ve already used brown sugar to fill your bee revival keyring, empty it, rinse it with hot water, dry it, and refill. Don’t offer the old batch to a bee.
Can you use caster sugar or icing sugar For A bee Revival Kit?
Caster sugar is fine. It’s finely milled white granulated sugar with nothing extra, and it dissolves faster.
Icing sugar is a big no. UK icing sugar nearly always has an anti-caking agent, usually cornflour and sometimes tricalcium phosphate. It won’t dissolve properly, it clouds the syrup, and it puts indigestible solids in front of the bee.
Granulated, caster and preserving sugar are all normally fine, but if the ingredients list anything other than sugar, do not use it. The ratio and method are in our guide to reviving a bee with sugar water.
Dissolve completely. Undissolved grains recrystallise in a narrow vial and block it. A common cause of a kit that will not give up a drop.
Why brown sugar is worse than it sounds
The major issue is the ash content inside the sugar. Refined white sugar sits at roughly 0.07 per cent ash. Honey is around 0.17 per cent. Unrefined evaporated cane sugar has been measured as high as 2.15 per cent, roughly twelve times the solid load of honey.
Bees have no way of dealing with that. In beekeeping, the result is dysentery, and it is a diet problem rather than an infection.
This builds up over time inside the bee. Honestly, one drop of brown sugar water won’t kill the bee sitting on your windowsill, but repeated feeds can and will.
The rule still stands because there is no upside. Brown sugar is not more nutritious; the bee is already stressed, and white sugar is the version that has been tested on millions of bees for decades.