oxalic - best before

[parkranger]

I used oxalic acid on my hives last winter with quite astounding results and plan to do again. The remaining contents of last years bottle of ------ Oxalic is stored in a garage cupboard and has not shown any signs of discolouration. Might it still be ok to use or might it have lost its efficacy.

 

[itma]

Oxalic syrup (with sugar) is what degrades. Quite quickly (weeks).

Oxalic on its own (waiting to be made up with syrup) should be fine.

 

[peteinwilts]

Purchased made up oxalic has a sell by date, which co-incidentally is just less than a year.... hhhmmm...

I had just under a litre over from last year. I kept some in one of my dark beekeeping stables and some in the fridge.


The stuff kept in the stable has turned yellow. The stuff in the fridge looks as clear as the day I bought it.

I will need to buy some more, but will be using the stuff in the fridge and will compare drop rates

 

[jenkinsbrynmair]

I will need to buy some more, but will be using the stuff in the fridge and will compare drop rates

As long as you're confident it's the mites not the bees that will be dropping - for the sake of saving what is after all a bit of loose change I wouldn't be taking the risk

 

[peteinwilts]

I would presume the oxalic gets weaker over time, so the bees would be in danger of underdose rather than overdose.

 

[MJBee]

I would presume the oxalic gets weaker over time, so the bees would be in danger of underdose rather than overdose.

I believe the danger is the build up of HMF in "old" oxalic/sugar syrup mix.

As JBM said it costs pennies to make it up fresh each time. Better safe than etc.

 

[ROACHMAN]

I would presume the oxalic gets weaker over time, so the bees would be in danger of underdose rather than overdose.

Its the HMF found in the sugar solution whch increases as it ages, it makes it poisinoue to bees.

 

[yeogi75]

get some crystals add to demineralized water and leave out sugar till wanted, we have some oxalic in demin in sample bottles in the lab that's six years old still good.

 

[MuswellMetro]

Anacdotally, one of my beginners bought Oxalic syrup from Thornes sale at Windsor and it was out of date by two weeks

They just stored it in the Kitchen not in the fridge until January , so it was over two months out of date when dribbled

Now whether it was badly applied or turned bad I do not know but they had heavy varroa loads and one hive had Varrosis, DWV, CPBV and Sac brood

So my advice is Fresh Made each year

 

[TOBY-3652]

I would say its not worth the risk... Buy some more fresh. I have just bought a litre made up from th////es £ 8.00 enough for 20 hives. Thats 40p per hive, why risk it ??????

 

[parkranger]

Thanks for the advice folks. It isn't so much a question of money but I didn't want to throw away what might have been useable. Only four hives to do but as you say "it's not worth the risk". Will buy some fresh ready for early January.

 

[itma]

You haven't said whether your Oxalic is mixed with sugar.

Until it is mixed with sugar as syrup there is no question of deterioration or "risk" of change. (Assuming reasonable storage conditions, properly closed non-metallic container, etc ...)


HMF is where the "risk" comes in.
The risk of killing bees.
Any acid promotes the breakdown of sugar into glucose and fructose - which is why you'll see "invert syrup" recipes that use acids (such as lemon juice or Cream of Tartar).
HOWEVER the same acid continues to act on the fructose produced creating HMF (which is brown). HMF isn't particularly dangerous for humans, but it is for bees. So an acidic sugar syrup that looks even vaguely brownish shouldn't be allowed near the bees.
AND that is also why you should not use acid-inversion of syrup for bees - even if it is normal in cake-making for humans and done on random YouTube redneck videos. It puts your bees at un-necessary risk.

Oxalic as crystals or as a pure water (no sugar) solution should be chemically stable.

 

[Outlander]

As long as you're confident it's the mites not the bees that will be dropping - for the sake of saving what is after all a bit of loose change I wouldn't be taking the risk

Agreed buy new for the small cost then your sure.

 

[parkranger]

Itma

Sorry, It's ------ pre-mixed.

 

[itma]

Itma

Sorry, It's ------ pre-mixed.

If its pre-mixed with sugar (ready to use) don't store it.

If its premixed with water (add your own sugar) then the no-sugar premix should store OK.
Without sugar present, HMF cannot be formed.
With sugar + acid then HMF will be formed but at a rate that would vary with temperature, exposure to daylight, etc ...

Premixed with sugar, it needs to be stored in the fridge (CLEARLY labelled) and best used within a matter of weeks.

 

[parkranger]

Itma

Thanks for the heads up but on a related matter...here we go again.

You have kndly pointed me in the right direction regarding stored Oxalic and this information I would think is of great help to other relatively inexperienced beekeepers. However, the blanking out of the supplier's name of this product does nothing to help anyone. I am not advertising their product, I am merely differentiating it from others.

Paranoia or what!

 

[Hivemaker.]

However, the blanking out of the supplier's name of this product does nothing to help anyone.

I agree, is it... P a y n e s.

 

[BKF Admin]

Paynes

There you go,I have also amended about another dozen suppliers so they show up.

 

[TryingToLetThemBee]

Thank you Mark and Pete! More Paynes, less pains!
<ADD> It was always a Thorne-y issue</ADD>

 

[alanf]

There you go,I have also amended about another dozen suppliers so they show up.

Very welcome, thanks. Downside is some vigilance that it's not abused, but a level playing field. Where it does come in useful is product comparisons:

The complete ready to use oxalic preparation sold by Paynes is made by the Italian firm Enolapi srl. It's a product available from many suppliers in three strengths. For some reason Paynes sell the stronger version with the yellow labels which is more suitable for Southern Europe. Not the place to go into the concentration debate but if you are using the Enolapi products, the most appropriate version for our climate is the one with the light blue labels and called "New Zealand formulation" as sold by Wynne Jones (and others). Always check the expiry date, it should be fresh which means nearly a year left and from a cool store room - not on a shelf where it's been in the warm sun over summer.

Talking of other suppliers, I saw the oxalic prep sold by Thornes under their own brand and their "Trickle 2" products comes with a warning: "These have a very short use by date - two or three months - as the mixture does deteriorate. We advise that you purchase it just before you are ready to use it." That actually applies to all ready to use oxalic solutions, including the Enolapi (whatever the date they print on the bottle).

An alternative commercial product to a fully premixed version (Enolapi or Thornes) is branded "Oxuvar" and also sold by Paynes among others. It is considerably more expensive, that may be connected with it being a registered veterinary medicine in some EU countries. It comes in two packs, add the sugar (which it calls "sucrose powder" - just pulverised sugar) to the pre-diluted oxalic to make half a litre of solution for immediate use. The two pack version will keep indefinitely until you're ready to make the final mix before use.

Or make your own, which I do because I know it's fresh, it will be the right concentration and I'll make just enough to use within a day or two.