Safety of calcium chloride as a honey desiccant - any chemists out there?

[Amari]

Last summer I wrote to the editor of BBKA News in reply to Wally Shaw's 'Readers' Questions'.
"Dear Editor
Wally Shaw (Harvesting unsealed honey, BBKA News, July 2018) suggests using a dehumidifier in a small reasonably air-tight room to reduce the water content of unripe honey in the comb to below 20%. I use a simpler method: my warming cabinet accommodates two 30lb honey buckets. In the cabinet I place two small trays of calcium chloride crystals - these are widely available to reduce humidity in boats and caravans over winter. I set the temperature at 35C for several days and find the percentage water content falls from say 21% to 18%. Check that the trays are not overflowing with absorbed water".

I hoped my letter would be published but not unreasonably she checked the safety of CaCl2 with an 'expert'. The editor replied with the 'expert's opinion:

"I have taken some advice on your idea from someone who is more expert in
this than me. And the response I got was:

"Calcium chloride is used widely as a desiccant, but it does get warm when it
absorbs water and it can corrode zinc and steel and can give off gases,
which can irritate the respiratory tract, skin and eyes. We consume it in a
variety of ways though and it is not harmful in that respect (indeed, it is
one of those essential substances that we need to keep us healthy), but I
guess, how much is used, whether it gets very hot and whether it is placed
in metals that it could react with - or what else is in the room - might,
potentially be a problem. Similarly, if it is hot and the beekeeper does not
realise and touches it, the skin contact could cause burns or irritation.
Similarly, if splashed into the eye - nasty!!! I have always used the powder
in glass vessels, but Giles does not mention heat or what his trays and
cabinet are made of - in fact he adds heat. In a lab setting, I would
usually wear gloves as a norm, so would not have any skin irritation
problems".

"So I am sure you will understand, I feel very hesitant about recommending
your method in BBKA News".

My reply was:

"Very sensible of you to check the safety profile of calcium chloride - but I think your expert’s opinion is OTT!
I realise you cannot publish my letter but allow me to make a few points:
1. The crystals absorb moisture imperceptibly slowly. There is no question of creating chemical heat. Burns due to touching the hot container are therefore impossible
2. Skin contact can cause irritation by desiccating the skin - not by a chemical burn
3. “and can give off gases” - then why is it widely used in damp cupboards, boats and caravans?
4. Yes it can irritate the eyes - take precautions known to us all.

Your expert “always uses the powder in glass vessels”. He/she leads a sheltered life - spare a thought for highway operatives using it as a road de-icer or swimming pool attendants using it to harden the water. By-the-by, calcium chloride used as a dessicant is in crystal form, not powder.

Just in case you have a damp cupboard at home I attach the stuff I buy (read Product Info) https://www.amazon.co.uk/Kontrol-Krystals-2-5Kilo-Refill-Moisture/dp/B01846ZFL0/ref=sr_1_3?
ie=UTF8&qid=1531924439&sr=8-3&keywords=kontrol+krystals".

And I followed up with:

"Hello Editor, sorry to bother you again!
I’ve been revising memories of A level chemistry (1959). Calcium chloride with water does not yield “gases”.
CaCl2 + H20 = CaO +2HCL. No gas, let alone gases, at all!!!
Could your ‘expert’ please enlighten me?"

The editor sent my response to the 'expert' for comment but unfortunately he/she has not replied. I'm sure there must be a few chemists on the Forum. I'd be grateful for your opinion on the safety of a small tray containing half a cup of CaCl2 in a warming cabinet.

 

[Curley]

HCl is actually a gas when pure.

CaCl will irritate wet bits of you - eyes, throat, sweaty hand etc As such I think it unlikely a responsible publication could recommend having open dishes of it standing around. The product you link to is designed as a refill for dehumidifiers etc where the chemical is presumably relatively safe from spillage and coming into contact with people.

 

[jenkinsbrynmair]

Unfortunately the BBKA types think that just mentioning 'expert' in a sentence makes it credible.
But as we can see from Margaret Murdin's statements regards Thymol and Nosema today that they don't bother consulting experts before publishing their guff

 

[Erichalfbee]

Unfortunately the BBKA types think that just mentioning 'expert' in a sentence makes it credible.
But as we can see from Margaret Murdin's statements regards Thymol and Nosema today that they don't bother consulting experts before publishing their guff

Yes totally wrong to say thymol is of no use against nosema but I suspect the statement is intended to be a warning along the lines of those issued about generic oxalic.

 

[SDM]

Isnt it used in the lids of fancy biscuit tins too?

 

[SDM]

Yes totally wrong to say thymol is of no use against nosema but I suspect the statement is intended to be a warning along the lines of those issued about generic oxalic.

There was a WBKA article last year that conspicuously avoided mention of thymol as a nosema treatment.
I guess saying nothing about it is better than blatant misinformation. I thought Margaret Murdin was meant to be an extremely well informed NDB type.

 

[Hivemaker.]

I thought Margaret Murdin was meant to be an extremely well informed NDB type.

...and very likely is... if it has anything to do with beekeeping pre 1947.

 

[Erichalfbee]

 

[TooBee...]

I can't see the harm in placing a couple of these in an air tight-ish cabinet with honey
https://www.amazon.co.uk/Kontrol-St..._rd_t=40701&psc=1&refRID=JMK02CJMK1KMP17YK72A
although I am completely ignorant about chemistry, so no one should pay attention to what I've just said

But... am I the only one to think, what effect would it have if one of these was placed ontop of the top super, with a wire mesh between it and the bees? Would it help the bees speed up the curing process, or do we all lack the curiosity (or know better) and have the attitude of leave them alone to do what they are expert in!

 

[Repwoc]

Desiccated bees, anyone?

 

[jenkinsbrynmair]

...and very likely is... if it has anything to do with beekeeping pre 1947.

 

[Repwoc]

https://www.cdc.gov/niosh/ipcsneng/neng1184.html

CaCl2 is routinely used in chemistry laboratories in drying tubes to prevent water vapour getting into water sensitive reactions. I think if it gave of any gas (HCl) then it wouldn't be much use as a drying agent.

 

[jenkinsbrynmair]

am I the only one to think, what effect would it have if one of these was placed ontop of the top super, with a wire mesh between it and the bees?

Probably

 

[Ian123]

Unfortunately the BBKA types think that just mentioning 'expert' in a sentence makes it credible.
But as we can see from Margaret Murdin's statements regards Thymol and Nosema today that they don't bother consulting experts before publishing their guff

so what was said?

 

[jenkinsbrynmair]

so what was said?

'Thymol is of no use against Nosema whether prophylactically or otherwise'

OK, her comments about it's use as a nosema treatment not being authorised is true, but that doesn't excuse her making misleading/untrue statements - she's the chair of the BBKA FFS!

 

[SDM]

...and very likely is... if it has anything to do with beekeeping pre 1947.

Ahh a dinosaur, had a recent encounter with one of them peddling rather out of date info.

 

[For want of a better word]

I still have a dessicator that uses CaCl, it has an indicator Cobalt Chloride that goes from blue (anhydrous) to pink (hydrated)... place in low oven to dry off and away yoi go again!

I think a warm room with a dehumidifier would be a safer option!

As for beekeeping before 1947 I have no idea... I was not conceived until a year later!

Nos da

 

[oliver90owner]

I don’t think so. That would be ‘tell-tale’ silica gel.

Calcium chloride is deliquescent, not just hygroscopic. I expect it is actually the amorphous form in fused lumps - it needs to be heated very strongly to rid the hydrated crystals of water. It may generate hydrogen chloride gas when still in the solid state, but when it dissolves in its own collected water, this would cease. But the reaction providing this is a bit flawed. It shows calcium hydrxoxide as product - which is basic and will react with acids. The difference is possibly that this can occur until the hydrogen chloride gas (a covalent compound) dissolves in water.

It will, when a fully saturated solution in an enclosed space, provide a constant humidity above with a relative humidity of 35% at 20 Celsius.

Spills are the most nuisance as the solution is quite corrosive. It is still used for ballasting pneumatic wheels due to the density of a concentrated solution. But any leaks will soon result in corroded wheel rims.

 

[beebopper]

HCl is actually a gas when pure.

Where do you get this from. Conc (pure) HCl is a liquid.

CaCl2 use is completely safe and stable - as long as you do not contaminate your honey I see not problems with this.
It does produce allot of heat if dissolved in a small volume of water (due to water bonding with the ions resulting in heat being generated). Be careful when disposing of it therefore - use large volume of water and add slowly before going down sink.
Cleapss Hazcard 19A (http://science.cleapss.org.uk/Whats-New/hazcards/).

Cannot see where people get this fictional chemistry from. Too much inappropriate and misunderstanding of google searches I suspect (well I know but was trying to be polite).

 

[beebopper]

I still have a dessicator that uses CaCl, it has an indicator Cobalt Chloride that goes from blue (anhydrous) to pink (hydrated)... place in low oven to dry off and away yoi go again!

I think a warm room with a dehumidifier would be a safer option!

As for beekeeping before 1947 I have no idea... I was not conceived until a year later!

Nos da

D- I am afraid.

You appear to be confusing Calcium chloride and cobalt chloride.

I would not use cobalt chloride as it is significantly more toxic. The chemistry of how it works is similar however.