Ignorance about toxicity and suitability of timber

[Les Symonds]

The lack of understanding among the woodworking fraternity, about the properties of some timbers never ceases to amaze me. A question was posed this morning, in a social media woodturning group, asking for suggestions of a UK-native timber suitable for making a pestle and mortar (well done to the guy who asked, for having the sense to ask). The first suggestion was olive, so the originator of the post repeated that he wanted a native timber. The next two responses were that he should use oak! One writer stated that oak has tight grain and that one should always check the toxicity of a timber before using it, so I challenged his words, in relation to both the properties of the grain and its toxicity. His response was to stress that all the toxins in oak are found in the leaves and in the bark, then he even went on to quote precise figures for the percentage of toxins and phenolic acid present.

I despair!

Les

[bodrighywood]

Very common problem Les. Number of turners who think laburnum and yew only have the toxins in the fruit for example whereas it is also present in the timber. Only part lof the yew that isn't poisonous is the flesh of the berry which is the part birds go for. Even sycamore can be dodgy as the seeds can prove fatal to horses. Bottom line look back at what woods were traditionally used and go by that. E.g. beech, sycamore and fruit woods. Oak has also been used traditionally for a lot of food items Les.

Pete

[John Plater]

Excellent responses, couldn't agree more. Toxins are present in the timber which is why a barrier such as gloves need to be worn by some people to prevent absorption through the skin. I for one have a problem with handling wet english walnut and finish up with a rash as well as a black stain ! My understanding is that sycamore is a particularly inert timber chemically speaking which is why it was used traditionally for butchers' blocks and cutting boards.

[julcle]

This is an interesting thread and one that pops up on here from time to time, I have used Oak in the past for food bowls and salad bowls because of it's durability and looks. What are the members views on using Beech ? I know it has a tendency to spalting - should that put a person off using it for food products ?
Julian

[bodrighywood]

As fgar as I can remember the spalting in beech is inert and not of any danger to humans. Beech was one of the traditional woods used end grain for chopping blocks. Sycamore has natural antibacr=terial properties as far as I can remember. The worst woods are amongst the tropical ones I suspect. Some like iroko and cocobolo can produce a dangerous reaction in some people. Always worth having a look at the wood database here if it doesn't frighten you off all wood turning LOL.

Pete

[The Bowler Hatted Turner]

I think spalting in any species is dangerous if the spores are still present. Oak in my opinion is a "dirty" timber. By that I mean that the grain can be so deep that food particles can get caught in it and not washed out easily.Jamie Oliver is to blame for people's use of Oak as he serves his food up on it all the time.(Can't he afford proper plates?)The white coloured woods, Beech, Sycamore and Maple are fine with food use and they also clean easily. Pine is good too as are the fruit woods. I would also hazard a guess that a Yew plate that has been washed up a few times should be OK too. The dust from Iroko is a real nuisance (I can't work with it at all) but also what people don't know is Oak is carcinogenic too, but only if the dust is inhaled in quantity, a bit like most woods I should suspect. Rosewood is a timber to be careful of as I have heard of people being sensitised to it and coming out in hives when handling it. At the end of the day from a H&S point of view if you are worried about it don't do it or use it.

[John Plater]

I am going back a few years but I can remember reading about exposure to the dust from spalted beech giving rise to symptoms of farmers' lung. It is the mycelia from the fungus which leave the spalting marks but I understood that fungal spores were present in the body of the timber too. I suppose that any sanding of any fungal matter is going to make it fine enough to become airborne and breathable.
I like the textured effects offered by grass tree roots but have to be very careful with extraction and air fed face shield. Banksia nuts can be a bit dusty too.

[Les Symonds]

There is a fascinating video on youtube, which deals with spalting. It's a talk by an American professor called Sara Robinson, who has written a PhD specifically about it. She de-bunks the myth about spores being poisonous and states that the air around us is constantly laden with fungus spores and we breathe them in every day. Check her talk out here... https://www.youtube.com/watch?v=fWedsgkoxYY. Her quote about the spores is at about 11 minutes in to the video, but it's worth watching the whole thing.
Les

[Bryan Milham]

Whereas I would not use ring-porous woods for some things, I personally don't have an issue with using woods to eat or drink from.

One thing I regularly fall back on is this article (in another forum), where it explains that wood is a safe medium for food use. It's not the full scientific explanation but an overview in 'Laymans language'

http://www.woodworkforums.com/f11/wood-kills-bacteria-775

[John Plater]

That sycamore is poisonous to horses is an interesting one. There is a toxin which is sometimes but not always found in sycamore seeds and occasionally the leaves. High levels of that toxin can be found in horses with atypical myopathy, a sort of muscle wasting disease.
Many trees are capable of producing toxins which they exude over the ground below them in order to prevent other stuff trying to grow and taking their nutrients. Sumac and English Walnut are examples which have been quoted to me in the past.
So, given the systemic nature of the trees, toxins are bound to be in the timber as well.

[fuzzyturns]

The other day I read an article from a woodturner reporting that after rough-turning a piece of spalted timber (can't remember the species) without protection, a few days later he ended up in hospital and almost died from a fungal infection of his lungs. Took some serious efforts from the docs to keep him alive and get him back onto his feet.

Having said that, I think this was a very exceptional case. It is certainly true that we are surrounded by spores everywhere, and it's therefore safe to assume that our bodies can handle most of them quite easily. I still wouldn't recommend ingesting spalted timber if it can be avoided.

Now, coming back to the original post: using oak for a mortar and pestle. I am not quite sure why Les was so aghast. OK, oak is an open grained wood, which makes it less than ideal for this purpose. And most of it has got loads of tannin, which will impart a nice vinegary taste onto whatever your pounding the hell out of. But other than that, it should be fine.  Wouldn't be my choice, to be sure, but the customer gets what the customer wants.

[bodrighywood]

Idf you use an open grained wood fpr a mortar particles of the spice or whatever you are grinding will remain in the grain tainting whatever you do next. It can, if grinding garlic mormsome such moist material leave partiocles that go rancid orm even mouldy. When this happens in a flat piece such as a chopping block it can be scrubbed hard but I for one don't fancy trying to scrub the inside of a mortar LOL. If you are doing this professionally you can actually be sued if someone gets ill using something you have made. not worth the risk. I'd say sorry, no can do and explain why.

pete

[The Bowler Hatted Turner]

Whereas I would not use ring-porous woods for some things, I personally don't have an issue with using woods to eat or drink from.
The prices you pay when you eat out I would expect a proper  plate 

[malcy]

Interesting thread this. I have just been asked to make some plates and bowls for eating off everyday, so some good advise here. Malcolm.

[Les Symonds]

... I am not quite sure why Les was so aghast. OK, oak is an open grained wood, which makes it less than ideal for this purpose. And most of it has got loads of tannin, which will impart a nice vinegary taste onto whatever your pounding the hell out of. But other than that, it should be fine.  Wouldn't be my choice, to be sure, but the customer gets what the customer wants.

I am left wondering if your comments are sincere, or rhetorical! I never claimed to be "aghast", and as regards the physical properties of oak, you seem to reinforce what I was saying, that the tannins impart a taste and that the open grain is most unsuited, but then state that the customer should get what she or he wants. This thread didn't start because a customer wanted oak, it started because a fellow woodturner asked what was a suitable wood for a pestle and mortar. I was simply amazed that the first two responses suggested oak.
Les