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Thymol Safety Data
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Thymol Crystals, Usage in beekeeping

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Thymol crystals are corrosive and nasty...

Harmful if swallowed, inhaled or absorbed through the skin. Eye, skin and respiratory irritant. Eye contact may cause serious harm.

Please handle them with care and use suitable protective clothing.

They have two main uses in beekeeping, the first of these is as an anti fungal and anti fermentation agent in the preparation of sugar syrup for feeding to bees.

R.O.B Manley propagated the idea of using thymol in syrup intended for winter feeding in order to prevent fermentation and the growth of mould.

Thymol is only slightly soluble in water, but it is readily soluble in surgical spirit (rubbing alcohol in USA) which is ethanol to which a small amount of methanol has been added, to render it unfit to drink. It is normally used to sterilize surfaces and to cleanse skin abrasions and to toughen skin.

By using surgical spirit we can first produce a 'stock solution' that is miscible with sugar syrup or honey.

Manley's recipe has become a standard and even if the requirement is for a stronger solution, this is often specified as '3x Manley strength' or '4x Manley strength'. His original recipe was one ounce of thymol crystals dissolved in five fluid ounces of surgical spirit to make the stock solution. Then half a fluid ounce of this mixture was added to 1 Cwt (112 lbs) of sugar, which he dissolved in 7 imperial gallons (8.75 US Gal.) of water for direct use as winter feed. These obsolete units convert directly into 28.5 gm thymol crystals to 142 ml surgical spirit which is a ridiculous way of expressing it. However 30 gm thymol dissolved in 150 ml of surgical spirit will give a solution of the same strength and the figures are both more manageable and more easily remembered.

The stock solution is added to syrup at the rate of one teaspoon to a three gallon (imperial) quantity of syrup. This converts to 5 ml of stock solution in 13.5 litres, which is not a brilliant way of describing it, but the final strength is not critical. I have several plastic 'jerry' cans that hold 15 litres and I use 1, 2, 3 or 4 teaspoons of concentrate according to the strength that I require.

The second usage that beekeepers have for thymol crystals is as 'non medicinal curative substance', which is means by which we in UK skirt around the need for approval as a veterinary drug for items like this, formic acid, lactic acid and oxalic acid in the treatment of bees against varroa.

The crystals are allowed to evaporate slowly by loading them into special frames... Two types of these are detailed on the Frakno frame and Brookes/Knight frame pages.

Thymol Crystals are Available From:- E.H.Thorne Ltd.

I neither endorse nor condemn this product. The information is published here is a matter of public record. The information is placed here for the education of those that wish to read it.

BEFORE you obtain or use the material concerned, please ascertain the legality of doing so in your location as the product may or may not be approved in your geographic State or Country.

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Originated... Summer 2000, Revised... 02 April 2003,
Corrosive icon Coding Standard 2003 Issue 2