Can I freeze oxalic acid?

[RoyCropper]

I have about 250 ml OA left over which might prove useful if I pick up a swarm this summer.
I know that OA in solution goes off over time so would it still be effective in 5 or 6 months if I freeze it it the meantime?

Thanks


Roy

 

[VEG]

What's the expiry date ?

 

[priono]

i would say yes as long as they stay dry cos its just crystals like salt.

 

[RoyCropper]

i would say yes as long as they stay dry cos its just crystals like salt.

This is already in solution not crystals. It was picked up from my local association in December so I suppose it's ok for a couple of months.

Ray

 

[alanf]

Yes, it would preserve better in a freezer than on a warm shelf but a) you don't know how it was stored before you got it and b) it's not ideal stuff to store in a family freezer.

It's not that it's less ineffective against mites after longer storage but it potentially breaks down the sugar to HMF which is poisonous to the bees.

If you want a "ready to go" solution that will keep indefinitely but you can preweigh before storing in the beeshed you could try the same method as the Swiss Oxuvar product. Premix 15g of oxalic dihydrate in 200ml of Deionized water in a strong half litre bottle with a wide top. Preweigh 200g of sugar in a bag. When you need oxalic for treating add the pre weighed sugar to the bottle of oxalic solution and shake until dissolved. That should give enough for around half a dozen swarms. Costing under 50p it's not worth keeping for more than a week or two.

 

[oliver90owner]

Less than 10g of oxalic and a few pence worth of sugar. +1 to Alanf. Is it really worth the bother?

 

[pargyle]

Less than 10g of oxalic and a few pence worth of sugar. +1 to Alanf. Is it really worth the bother?

Or the risk ? For a few pennies ...

 

[Erichalfbee]

Bin it, buy some crystals and make your own as needed. Easy. 100 mls water 100 grams sugar and 7.5grams oxalic. Done.

 

[alanf]

Or the risk ? For a few pennies ...

Risk is relative. Using premix, the risk is that you don't know how it has been stored. Financially the temptation is to hang onto part used containers because it comes in fixed amounts and it's not always easy to get more (1 litre or 500ml is what I can see). I don't think it's particularly easy to handle as supplied because to fill a 50ml syringe you have to decant to a wider mouth container.

Mixing your own you might see the risk as getting it wrong, but if you can measure for cooking, you can measure for treatment. I see at least one advantage in choosing the container you mix in. Wide mouth robust plastic is ideal, no decanting. Another is you know what is in it and can compare with the research papers, reproduce the same oxalic and sugar concentration for instance. And you know how it has been stored since it was mixed.

There's a big premium for the minor convenience of premixed, 500ml of the Enolapi product is what? Several pounds delivered. The Swiss Oxuvar seems to be 11 quid before postage. Ingredients for making your own would be about 20p for supermarket deionized water, 30p for sugar, about 30p for oxalic. Cost depends on amounts you buy and where, but well under a pound for 500ml and you can make up 100ml quantities whenever wanted, never needing to store the mixed solution even for a few days.

Maybe I'm more confident than most, I'll admit university lab training. It's not rocket science, it is however, your choice.

 

[itma]

If it is in a Trickle2 dispenser bottle (or something else similarly useful), dump the remaining contents, then wash out and store away the container.
Order in some crystals (they essentially keep indefinitely), and (if you don't have some) a set of under £10 "pocket scales" from eBay so you can weigh tiny quantities extremely accurately.

 

[TOBY-3652]

Less than 10g of oxalic and a few pence worth of sugar. +1 to Alanf. Is it really worth the bother?

 

[RoyCropper]

Thanks for all the advice re: mixing your own. I didn't realise it was so cheap/easy.

I've only had OA premixed by my local association before and haven't been able to get hold of it in the Summer.

Roy