This section is from the book "How To Keep Bees And Sell Honey", by Walter T. Kelley. Also available from Amazon: How To Keep Bees And Sell Honey.
Honey is normally packaged for bulk storage in 5 gallon square tin cans or in 50 gallon steel drums and during cold weather most of this honey granulates. Formerly these cans and drums were placed in tanks of water and heated until the contents became completely liquefied, but this was slow and costly and the honey was darkened by the continued over-heating of the outer liquid honey before the inner core of granulation become liquefied.
A much better system of liquefying honey is to place the filled containers in an insulated hot box or hot room from which it drains as rapidly as it is melted and then further heated in a double boiler with a mixing paddle so that none of the honey is ever heated to over 150 degrees F.
Large beekeepers can build a walk-in hot room along the general lines of the hot box described and pictured here for small beekeepers and install an automatic sump connected to a pump and motor to pump the honey into the double boiler, heating and mixing tank, as it is liquefied.
If you buy or store honey in 60 pound cans or large containers, the best way to liquefy it is in a hot box or a hot room arranged so that the honey runs out of the chamber as rapidly as it is liquefied to prevent its over-heating. The more insulation you use the more efficient the operation.
The small beekeeper can build himself a hot box in a few hours and at small expense using 2" x 4" studding, covering the inside and outside with 3/4" celotex and lining the inside with corrugated or 5-V galvanized steel roofing or flat galvanized steel sheets. A box about 20 inches wide by 40 inches high and 80 inches long inside will hold 10 of the 5 gallon tin cans and a unit heater which will liquefy the honey in about 12 hours. The box should be raised up high enough from the floor, and the legs at one end set back 12", so that the honey, as it is melted, can run into a double boiler for further processing and the double boiler should be high enough to draw the processed honey off into retail containers. The stand and the box can be built as a unit or separately.
A door should be made to cover one of the 40" x 80" sides, using 1/2" moisture-proof plyboard covered with 3/4" celotex on both sides and a flat sheet of galvanized steel on the inside, hinged at the top and counterbalanced and all edges should be made tight with weather-stripping. A pan about 6" high loosely covering the bottom, tilted to drain at one end into a double boiler, with a 1 1/2" or larger drain flange will catch the melted honey as it flows from the cans. This pan should be covered with 1/4" galvanized hardware cloth to hold any chunks of unmelted honey to prevent it from clogging the outlet.
Most any kind of dry heat is suitable, but most will find the 1300 and 1600 watt FAN-FORCED ELECTRIC HEATERS the cheapest installation and with the double celotex insulation very economical to operate. Install a hot air furnace thermostat setting the high limit at 170 degrees and the low limit at 130 degrees F. The temperature inside the box will not rise much above 135 degrees until most of the honey is melted BUT THEN THE TEMPERATURE WILL RISE RAPIDLY. To insure circulation of the hot air in the box, attach the unit heater to the 2" x 4" 's in either top end of the box and then box it in tightly with the celotex and the metal covering to within 8" of the bottom, which will give an open space of 2" above the pan, forming a baffle, the fan pulling in the cool air from the bottom, and blowing hot air out at the top.
Above the pan install two 2" x 4" 's or 2 lengths of 1" galvanized pipe lengthwise to support the cans on about a 15 degree tilt for good drainage. Before placing the cans in the box secure a strip of 24 gauge or heavier galvanized steel 1" to 1 1/2" wide and about 5" long and bend it into a U shape and force it into the threaded opening with the legs at right angles to the top of the can so as to prevent chunks of granulated honey from clogging the outlet. Then put the cans in place as pictured, leaving one inch or more space between each can for the air to circulate and on top of the first row place the two halves of a 2 x 4 scantling, ripped in two, length ways and place the remaining four cans on these. Then with an eight penny nail punch a hole in the top edge of the bottom to prevent a vacuum.
Keep in mind that the saving in electricity will quickly pay for the extra investment in building a very tight box with extra thick insulation and weather stripping.
 
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