Holly?

[Broch]

But I don't believe it is worth knowing that a minute amount is there - if it even is. Do you believe it's worth knowing that all bottles of malt whisky contain methanol? No, because the levels are so minute that they cannot do you any harm. There is no mention of any poisoning anywhere from Ilex aquifolium other than caused by the saponins in the berries eaten by children. In fact, I can find no published data about cyanogenic glycosides (saponins are triterpene glycosides) and there are no warnings published anywhere that I can find about toxins in the wood of holly. My conclusion is that there is absolutely nothing to worry about!

Perhaps the best resource, though there are others:

Ilex aquifolium L. (PIM 272)

Forgive me please, plant usage, and consequential toxicity or non-toxicity, is a passion of mine. I get frustrated when things are labelled as poisonous or dangerous when really there are only harmless levels of trace toxins.

 

[TLM]

And where is a resident organic chemist who could tell how to break down the toxins safely. Amygdalin one of the non healthy chemicals in many seeds apparently breaks with acids but gives up hydrogen cyanide that is even unhealthier. Once it is out though it is no longer even a potential threat.

 

[Suffolkrafter]

But I don't believe it is worth knowing that a minute amount is there - if it even is. Do you believe it's worth knowing that all bottles of malt whisky contain methanol? No, because the levels are so minute that they cannot do you any harm. There is no mention of any poisoning anywhere from Ilex aquifolium other than caused by the saponins in the berries eaten by children. In fact, I can find no published data about cyanogenic glycosides (saponins are triterpene glycosides) and there are no warnings published anywhere that I can find about toxins in the wood of holly. My conclusion is that there is absolutely nothing to worry about!

Perhaps the best resource, though there are others:

Ilex aquifolium L. (PIM 272)

Forgive me please, plant usage, and consequential toxicity or non-toxicity, is a passion of mine. I get frustrated when things are labelled as poisonous or dangerous when really there are only harmless levels of trace toxins.

Nothing to forgive Broch, it's a passion of mine as it is yours, and I do take your points. As for what toxin levels qualify as worth knowing, I'm not sure what the answer would be. Personally I enjoy learning about the chemical constituents of plants, I find it interesting. But in any case, as I said, I don't know what the levels in the wood are. The berries and leaves contain many toxins one of which I thought was menisdaurin, a cyanogenic glycoside. Happy to be corrected though. Whether or not anyone has specifically studied levels in the wood or bark, I don't know without looking into it further.

 

[Suffolkrafter]

And where is a resident organic chemist who could tell how to break down the toxins safely. Amygdalin one of the non healthy chemicals in many seeds apparently breaks with acids but gives up hydrogen cyanide that is even unhealthier. Once it is out though it is no longer even a potential threat.

Sorry if this is somewhat off topic, perhaps it warrants another thread as this doesn't relate to holly specifically. But hopefully it is of interest to some and answers the above question to some degree. I'm a biochemist by trade and couldn't resist answering. Having said that, I'm happy to be corrected if any of this is wrong:
Amygdalin is broken down enzymatically by hydrolysis (a chemical reaction with water resulting in breakup of molecule, catalysed or facilitated by enzymes), first to prusanin (which in itself is also present in some plants) and subsequently in two further steps to produce hydrogen cyanide and benzaldehyde (and glucose).
These hydrolysis steps can take place in the intestines, and with resulting hydrogen cyanide being readily absorbed through the gut wall, toxicity results if too much is consumed.
The enzymes are also present in plants, so if for example, an amygdalin containing seed is crushed and kept wet, the amygdalin is then converted to hydrogen cyanide, by the process described above. Amygdalin is stable at temperatures typically used in cooking, but heating will drive off hydrogen cyanide which boils at around 25 c.
There are examples of people using variations of this method, for example bird cherry fruit and seeds were widely eaten after preparation in certain parts of the world. Cassava root is worth looking up. Inadequate removal of cyanogenic glycosides from the root results in a disease called konzo due to chronic exposure in parts of the world where it is eaten, which is exacerbated by deficiencies in certain amino acids (which impedes the body's ability to remove hydrogen cyanide). But again, the cassva root can be rendered safe by grinding, soaking and allowing the enzymes present to hydrolise the cyanogenic glycosides.
There are also 'industrial' methods used in production of bitter almond oil for example, but I don't know much about this.
What I don't know, and I would like to know, is if a cyanogenic glycoside-containing plant can be safely assumed to always contain enzymes that metabolise it. Clearly some plants do.
I wonder if a long long time ago (pre-agriculture perhaps) in the UK similar methods were used, for example with species of fabaceae and so on. But I guess that selective breeding in agriculture has gradually bred the toxins out of the species we now eat.

 

[TLM]

I knew about the enzymes but thought that might not be relevant to the wood but I don't know that. Generally making a wooden vessel safe is of some interest I believe.

I read somewhere that several acids can break down amygdalin and I guess some glycosides too. Acetic acid actually changes wood to better serve as a vessel as it lessens the effects of water on some properties, the most relevant being coefficient of moisture expansion.

 

[Suffolkrafter]

I knew about the enzymes but thought that might not be relevant to the wood

Yes my post was quite off topic really and I have to say I didn't have wood in mind when I wrote it. There is such a thing as chemical hydrolysis of glycosidic bonds, by acid or bases, but in aqueous or methanol solutions. I think at high temperatures. I'm not sure how applicable this would be to the scenario of treating wood. Amygdalin is water soluble so oiling wood would presumably act as a barrier - I think Broch already mentioned this.

 

[TLM]

so oiling wood would presumably act as a barrier

Especially if properly polymerized so it is bonded to the wood and stays in place.

 

[Robson Valley]

I use an oven-baked vegetable oil finish on my carved spoons and forks. Applied at 350F, you can't wash that out in boiling soup.

Oiling the wood at room temperature still leaves the wood air vulnerable to expansion by hot foods, blowing the oil finish away into your food and then to be replaced by decomposing food liquids.

 

[Danqrl]

Good thread guys lots of info to digest, as a relative newbie still the only thing i heard about holly previous is that the if you burn it the smoke that is produced can be harmful. No clue as to exactly how harmful was given though.

I just remembered something from Paracelsus that I picked up from a Paul Kirtley seminar...

All things are poison, and nothing is without poison, the dosage alone makes it so a thing is not a poison.

—Paracelsus, 1538[1]

 

[TLM]

Oiling the wood at room temperature still leaves the wood air vulnerable to expansion by hot foods

Here they sell a linseed oil that is catalyzed so that when exposed to air it hardens in about 3 days at room temp. No baking needed. It is normally used on wooden flooring. Hmmm... have to check how healthy that cobalt based catalyst might be.

 

[Robson Valley]

I use an uncatalyzed kalamata Greek olive oil for the complete process in 3 minutes and 30 seconds. The oil cannot go rancid, down inside the airless wood! No second treatment is ever required. Gases expand when heated. The physics of Charles' Law does the work for me.

 

[Kadushu]

If amygdalin is water soluble then surely the simplest way to deal with it in wood is to soak the wood in water? Any free amygdalin should wash out and any that is trapped shouldn't pose a risk anyway, especially after oiling. Not that I'm suggesting the use of seriously "poisonous" woods for food vessels.

 

[Suffolkrafter]

I know nothing about wood treatments really. But this bonding of oil to the wood sounds similar to seasoning cast iron?

 

[TLM]

But this bonding of oil to the wood sounds similar to seasoning cast iron?

Yes and no, he heats up the wood then spreads cold oil on it, air in wood pores contracts and sucks the oil in. After that he heats it up again that causes the unsaturated oil to polymerize into and on the wood. Not a bad trick at all. Just don't try it with coconut oil, it would not work.

The same heating trick is sometimes used if one wants a lacquer layer without any air bubbles.

 

[TLM]

If amygdalin is water soluble then surely the simplest way to deal with it in wood is to soak the wood in water?

It very likely leaches out slowly so if a slightly more aggressive treatment breaks it up that would be a lot faster.

 

[TLM]

Did some googling or actually ducking and found this, lots of fairly exotic species but more than enough normal European ones, holly not mentioned.

 

[Broch]

Did some googling or actually ducking and found this, lots of fairly exotic species but more than enough normal European ones, holly not mentioned.

It's interesting that very few are recorded to have any gastronomic or cardiac effects at all, that Holly has no mention, yet Maple, a recommended wood for bowls, spoons, cups etc. is listed.

I rest my case

 

[TLM]

It's interesting that very few are recorded to have any gastronomic or cardiac effects at all, that Holly has no mention, yet Maple, a recommended wood for bowls, spoons, cups etc. is listed.

I rest my case

I don't disagree. Birch too, pollen is problematic to some but never heard about the wood.

 

[Kadushu]

I wonder whether spalting ever plays a part or even fungi that do not appear in the wood but are present. A lot of edible fungi upset my stomach, so I'm pretty sure some unidentified wood fungus would do the same.