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Thymol in sugar syrup

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GDB 

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From reading several forums and Randy Oliver's website it seems that thymol can be used for preventing fungal growth in sugar syrup and also for treatment of nosema (although not licensed for the latter). The commonly recommended concentration seems to be 0.44mm thymol, which is an effective level for preventing fungal growth:

http://scientificbeekeeping.com/the-nosema-twins-part-5-alternative-treatments/

0.44mM is 0.066g thymol / litre and at this level the sugar solution apparently does not have an appreciable thymol smell.

Thornes sell thymol and state that 2 teaspoons (10ml?) of a 20% alcoholic solution of thymol should be added to 1 gallon (4.55 litres) of syrup. This works out at 0.43 g / litre, so is >7 more concentrated than the recommended dose of 0.44mM and the resulting syrup does have a very strong thymol odour. A Beesource member suggests adding 1 ml of 20% thymol to 3 litres which is 0.066 g / litre or 0.44mM

http://www.beesource.com/forums/showthread.php?215806-Natural-treatment-for-nosema

Have there been any studies on the levels of thymol which can be tolerated by bees?

'Teaspoons', are hardly the most accurate measurements available! Or have Thornes made a mistake on their thymol label? Why don't they say so many mls?
 

Hivemaker. 

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Thymol has been used in syrup for feeding bees since the 1940's.
 

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I'm feeding thymol syrup as per Hivemaker's recipe, but am having trouble with the sugar crystallising in the bottom of one Ashforth feeder. Does sugar, like honey, only need a few crystals to act as 'seeds' before crystallising throughout? In which case I probably didn't ensure it was all properly dissolved, though I thought it was at the time. Is there any way I can clear it (eg slightly warm weaker solution into it) or am I going to have to remove, scrape out and wash out the feeder before I can re-use it? Anyone else been there please?
 
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Tom Bick 

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As I understand it and may be wrong there is a limit to how much sugar can be dissolved into water and 2 – 1 is just about on that limit any higher and the sugar starts to reform into crystals and the colder the syrup gets the more crystals form.

I have had this problem in the past and found that if you make your next batch up with slightly more water than the last it should stop the crystals forming.

Also just before you refill the feeder break up the sugar with the hive tool and add the syrup if your bees have access to the feeder once the syrup drops to low levels you just may be surprised to see the sugar gone.
 

GDB 

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Thymol has been used in syrup for feeding bees since the 1940's.
I agree that Thymol has been used for a long time, but anything, including water, can be toxic. My question is does anybody know at what level thymol can start to have adverse effects on bees? Is the LD50 for thymol known in bees? The LD50 for oral thymol in rats is 980 mg / kg. Also there is big difference between ingesting thymol in the syrup and having thymol vapour in the hive atmosphere.
 
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Bees are not mammals, moles are, but I think there is some confusion here of what type of mole we are on about, as a millimole is a lot different from a millepede.

Temperature and your height above sea level ( ie atmospheric pressure and external ambient temperature ) can have an influence oh how sugar will crystalize out, adding thymol would alter this also

30g thymol dissolved in 5ml isopropyl alcohol, added to 140ml aqua dest and 1 teaspoonfull lecthin.
5ml of above exlir per gallon of 2:1 sugar dose it for me

anyone know if thymols isomer works as well............ name of it escapes me!
 

GDB 

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Bees are not mammals, moles are, but I think there is some confusion here of what type of mole we are on about, as a millimole is a lot different from a millepede.

Temperature and your height above sea level ( ie atmospheric pressure and external ambient temperature ) can have an influence oh how sugar will crystalize out, adding thymol would alter this also

30g thymol dissolved in 5ml isopropyl alcohol, added to 140ml aqua dest and 1 teaspoonfull lecthin.
5ml of above exlir per gallon of 2:1 sugar dose it for me

anyone know if thymols isomer works as well............ name of it escapes me!
Carvacrol is the isomer of thymol. While thymol dissolves in water at about 1 g per litre, carvacrol is practically insoluble in water, so that could be the start of a problem there.
 

victor meldrew 

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As I understand it and may be wrong there is a limit to how much sugar can be dissolved into water and 2 – 1 is just about on that limit any higher and the sugar starts to reform into crystals and THE COLDER IT GETS THE MORE CRYSTALS FORM
Not quite :)14C is the optimum temp for crystals to grow :)
VM
 

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I agree that Thymol has been used for a long time, but anything, including water, can be toxic. My question is does anybody know at what level thymol can start to have adverse effects on bees? Is the LD50 for thymol known in bees? The LD50 for oral thymol in rats is 980 mg / kg. Also there is big difference between ingesting thymol in the syrup and having thymol vapour in the hive atmosphere.
I have fed at five times Manley with no adverse effects,and bees remove,eat, apiguard and other thymol formulations which are very strong in thymol, with no apparent ill effects. So i would say the lethal dose would have to be very strong,neat thymol perhaps.
 

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Hi GDB
You are on the right line with your thinking, but if you dig a bit deeper from Randy Olivers trials you will find that the 0.44mM rate came from a guy called Yucel. Randy tried that rate in thick syrup but without much success. The thinking is that Yucel was using thin syrup which the bees would reduce down when they processed it. So if we are to have the same success as Yucel we need to compensate for this. With this in mind I try mix thymol in syrup as rule in the 0.9 - 1.2mM range or 3-4 times the Manley rate. Incidently I worked out Th***es rate as being 2.9mM so plenty of room to play with as Hivemaker suggests.
Manley says "although I have fed thymol in my syrup for six or seven years, it has done my bees no harm whatever, and it has been of some assistance, in my opinion at all events, in helping bees to winter well". His experience says yes it OK, all we need is the science to explain it to us. (google "Yucel 1142 - 1145 2005" select full pdf file)


iand
 

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"So i would say the lethal dose would have to be very strong,neat thymol perhaps"

perhaps - but then since you can put neat thymol crystals in the hive with no ill effects faffing around with these minor details is likely an irrelevence.
 

GDB 

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I have fed at five times Manley with no adverse effects,and bees remove,eat, apiguard and other thymol formulations which are very strong in thymol, with no apparent ill effects. So i would say the lethal dose would have to be very strong,neat thymol perhaps.
Many thanks! So bees can tolerate quite large amounts of thymol!
Incidentally I was interested in your observation in your post cited by Skyhook above about the oil which contains thymol floating on the surface of the syrup. Did this occur with both surgical spirit and isopropyl alcohol?
 

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"about the oil which contains thymol floating on the surface of the syrup. Did this occur with both surgical spirit and isopropyl alcohol?"

yes - hence the need for the lecithin emulsion.
 

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I notice that over time,the lecithin falls to the bottom of the bottle of stock thymol/surgical spirits solution. Does anyone have any thoughts about this? Once shaken the lecithin goes back into emulsion and the solution is no longer transparent.

What I need is a freely available staning agent that, like thymol, is soluble in alcohol, but not in water, in order that I can view the effects of the solution when added to my sugar solution. I'm happy to add it to a two litre bottle of syrup to view the performance of the emulsification process first hand. The problem with thymol and sugar syrup is that it is difficult to know if the thymol is on the top or not.

Either way, the bees love it, but my curiosity just needs to know first hand with my own eyes.
 

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I notice that over time,the lecithin falls to the bottom of the bottle of stock thymol/surgical spirits solution. Does anyone have any thoughts about this? Once shaken the lecithin goes back into emulsion and the solution is no longer transparent.

What I need is a freely available staning agent that, like thymol, is soluble in alcohol, but not in water, in order that I can view the effects of the solution when added to my sugar solution. I'm happy to add it to a two litre bottle of syrup to view the performance of the emulsification process first hand. The problem with thymol and sugar syrup is that it is difficult to know if the thymol is on the top or not.

Either way, the bees love it, but my curiosity just needs to know first hand with my own eyes.
While there may be other alcohol soluble/water insoluble dyestuffs, there is one, nigrosine, which comes in three varieties: Nigrosin water soluble (Acid black 2), Nigrosin oil soluble (Solvent Black 7), Nigrosin alcohol soluble (Solvent Black 5). However as to being freely available.... Your best bet might be to try the histopathology department of a large hospital and see if they could give you a small amount. There are other dyestuffs (e.g. Oil Red O and Sudan Black) which are oil soluble and may colour the 'oil' floating on the surface. These latter two dystuffs will not dissolve in water. I do not know whether lecithin, which is not a single compound but mainly a mixture of the diglycerides of stearic, palmitic and oleic acids linked to the choline ester of phosphoric acid, will be stained with the above dyestuffs.

Oil Red O will dissolve in alcohol - if you want to try I can send you some - but how to get your address?
 
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