YELLOW FINE CRYSTAL POWDER COMING OUT OFF ELM BOARD

[QUILLS]

I produce and sell wooden kitchen chopping boards of which I have been working with a batch of untreated UK elm boarding. I have produced many boards from the batch over the last year with no problems except one customer who purchased one in September and has had it leaning on wall in kitchen, standing on floor not used yet or further oiled. The kitchen is modern, warm and dry HOWEVER bright lemon yellow powder which looks like tiny crystal is being emmited from some of the rings in the wood. The only finish I have given the board is several layers of food safe mineral oil, like I have done on the others.
Please, can any one shed any light as to what this yellow stuff is. I have trawled the internet for the past 2 days with no inkling as to what it could be.
Thanks - Quills

 

[Doug B]

I've certainly had the same yellow crystalline substance come out of knots in pine, particularly on some doors I made that were south facing. I believe it is sap that seeps out but dries & crystallises very quickly.
Could be you have a small sap pocket in the elm & the warmth is causing it to leech out.

 

[QUILLS]

Hello Doug B. Your comment does make sense although I have never heard or seen this before. I think maybe the kitchen floor has underfloor heating because it does look as though the wood has dried out quickly.
I'll check and keep you updated.
Many thanks
Quills

 

[mickthetree]

Hi Quills - out of interest what mineral oil do you use? There seems to be a great deal of confusion as to what it is. USA - UK translation seems muddled on the internet. Where do you get yours?

 

[QUILLS]

Hello Mick - the mineral oil is Catskill Original Butcher Block Oil for culinary boards. The ingredients are 100% mineral oil with trace of Vitamin E. I get it from a small kitchenware shop in Banbury called Abaraxs. I have trawled the internet to find it in bigger bottles than the expensive 8fl oz bottle but can't find anything out. I also contacted Catskill direct (catskillcraftsmen) - they don't sell it was the reply!!

However my inkling now is that the yellow powder is a sap pocket as suggested by DougB in the previous post. But I am interested to hear what you and others have to say. I still have a lot to learn about wood.

Many thanks - Quills

 

[mickthetree]

Thanks Quills. I've not worked with Elm yet. I have only ever found pockets of sap in softwoods and they do act the same. If left somewhere warm they can leach out then crystallise as described. I wasn't aware this occurs in hardwoods too.

 

[QUILLS]

it did seem a little odd as I have had a large amount of this elm and have not seen this effect before. It also transpires that the board in question is kept in identical conditions as to home here with no underfloor heating so perhaps it's just 'one of those once not too often querks'!