Soon we will be heading into cooler weather. The concern here in the South Carolina Midlands isn’t the cold. It doesn’t get too cold here for the bees. They will cluster and as long as they have 1) honey, 2) enough bees, and 3) a dry cavity they are fine. With these three conditions present they will make their own heat and do well. The concern is moisture within the hive. The moisture is deadly as it will drip on the bees and wick away the heat, chill them, and they will die. If you don’t believe in the power of moisture to wick away the heat I encourage you to get out tomorrow morning and wash your car. What seems like a beautiful fall morning will chill you to the bone. If that fails to convince you try it again when the temperature falls to freezing.
I got the following from over on the Bee-L discussion list. It’s something to think about as temperatures drop and moisture in the hive condenses and becomes dangerous. The information below did not come with a named author.
Here’s some math on 100lbs of honey with 20% moisture… nice round numbers to keep the math simple: 20% moisture on 100lbs (45.4kg) of honey is 9.08kg of water which at 1L per kg is 9.08kg of water.
Now for the rest of the honey:
This quantity of honey is 80% (80lbs) of fructose. Molar mass of fructose (C6H12O6) = 180.72g/mol
6 Carbon -> 12.01g/mol x 6 = 72.60g/mol
12 Hydrogen -> 1.01g/mol x 12 = 12.12g/mol
6 Oxygen -> 16.00g/mol x 6 = 96.00g/mol
Total = 72.60g/mol + 12.12g/mol + 96.00g/mol
80lbs of fructose = 36287g
36287g of fructose / 180.72g/mol = 201 mol of fructose.
For future ease, lets round this to 200 mol of fructose.
Fructose is consumed by the bees and burnt with the oxygen they consume to release carbon dioxide and water. Here’s the balanced formula:
C6H12O6 + 6O2 -> 6CO2 +6H2O
Since 80lbs of fructose is roughly 200mol of fructose we need 1200 mol of oxygen to produce 1200mol of carbon dioxide and 1200mol of water.
200[C6H12O6] + 1200[O2] -> 1200[CO2] +1200[H2O]
Water as a molar mass of 18.02g/mol.
So 1200mol of water x 18.02g/mol = 21.6kg of water.
At 1L per kg we get 21.6kg of water released in the consumption of 80lbs of fructose.
So the total water in 100lbs of honey at 20% moisture is 9.08L + 21.6L = 30.68 liters of water.
If getting over 30L of water off of 31.5L (110lbs) of honey still sounds crazy, realize that the bees will have to consume 38.4kg of oxygen to metabolize the honey. So 45.4kg of honey and 38.4kg of oxygen combine – through the wonders of cellular respiration – to release 30.7 liters of water inside the hive.
The best and cheapest method of lowering the moisture problem is 1) providing adequate ventilation. My inner covers have an upper entrance cut into them. If the colony’s population is robust I just leave the upper entrance open as during summer. If the bees have decreased in numbers I may flip the slot so that it is on the top of the inner cover, or screen it, to prevent intruders while still providing ventilation. 2) Reducing the water in syrup to a 2:1 mix this time of year also helps to start reducing the amount of moisture within the hive. 3) As it gets colder, I have also tried removing all liquid feed and place a feeding shim with dry sugar on top Some people simply pour dry sugar on top of a piece of paper placed on the top bars or on the inner cover (Mountain Camp Feeding). The sugar acts as a desiccant and absorbs the humidity. The bees feed on any sugar that the condensation liquifies. It’s a two birds with one stone situation. 4) My first year I placed an extra box on top of the inner cover and inside I placed an old quilt. I was surprised at how damp/wet it got with condensation. 5) I have a friend that has some sort of fiber board that absorbs moisture. He places them over the bees (top box) and it wicks away the moisture keeping it from dripping on the bees. For people with money, they are available precut from the bee supply stores and in building supply stores under the name Homasote.
Start inspecting underneath your inner and outer covers for signs of condensation or mold. If it’s staying wet, dripping, etc increase ventilation or use other means to help them stay dry.