Tannin/Iron Staining, Oak Galls

[custard]

If you want to stain timber black using tannin/iron stain, then the very best source of tannin are ground up Oak Galls. Strong tea and stewed oak bark are both excellent (and more convenient) alternatives, but for the very best, deep blue/black then use Oak Galls.

Right now I'm seeing loads on the Oak trees near me, this is what they look like,

We're entering a favourite time for foraging, so a forest walk right now is especially productive. As well as Oak Galls I'm usually coming back from dog walks in the New Forest where I live with loads of Blackberries, Mushrooms, Elderberries and Cob Nuts. And in a few weeks there'll also be Sloes, Raspberries, Beech Nuts, and Chestnuts.

 

[thetyreman]

when it stops raining here I'm going to go foraging for sure, there's a few local oaks near me, never been gall hunting before.

 

[pitch pine]

Picked some ceps on Tuesday, couldn't believe my luck finding them. Seems it is a good mushroom/fungi year.

 

[memzey]

Hi Custard.

I’ve seen some things I think are oak galls coming off the oaks near me (Herts) but they are not perfectly round like the ones you show. Rather they are a bit knobbly looking with small flats on the outside. Are they the same thing and would they work for ebonizing as well? I’ll try to grab a picture later if you’re not sure what I mean.

 

[Woody2Shoes]

Hi Custard.

I’ve seen some things I think are oak galls coming off the oaks near me (Herts) but they are not perfectly round like the ones you show. Rather they are a bit knobbly looking with small flats on the outside. Are they the same thing and would they work for ebonizing as well? I’ll try to grab a picture later if you’re not sure what I mean.

Yup we've got loads of the distorted ones, as opposed to Custard's nice round ones, I think they're called Knopper galls:

https://en.wikipedia.org/wiki/Andricus_quercuscalicis

https://www.theguardian.com/environment ... oaks-wasps

Apparently there are more than 30 different kinds of gall wasps, plus loads of other opportunist infections and parasites on the wasps/larvae, so I guess there's scope for quite a lot of variation in galls.

I don't know about the tannin levels in the Knopper ones - they're relatively new to the UK so unlikely to have been used here in the past - but I guess the high tannin levels in a gall are the tree's natural defence mechanism against pests/infection, so it's probable that the Knopper galls are high in tannin too. Anyone fancy an experiment?

It's been a very big year for wasps in general (including hornets).

Cheers, W2S

 

[thetyreman]

I can only find the knopper ones near me as well, the're are plenty of them around luckily.

 

[memzey]

Are they any good though? Has anyone tried them out?

 

[custard]

Yup we've got loads of the distorted ones, as opposed to Custard's nice round ones, I think they're called Knopper galls

I've never heard of them before, you really do learn something every day! At a guess I'd think they'd be just as good, galls are a reaction by the tree so I suspect they're all ultra rich in tannin. They keep for years so it'd be worth getting some while they're there.

 

[El Barto]

We're entering a favourite time for foraging, so a forest walk right now is especially productive. As well as Oak Galls I'm usually coming back from dog walks in the New Forest where I live with loads of Blackberries, Mushrooms, Elderberries and Cob Nuts. And in a few weeks there'll also be Sloes, Raspberries, Beech Nuts, and Chestnuts.

It has been a bumper year for blackberries!

 

[thetyreman]

I went out today again and managed to find 3 of the rounded ones, but the rest are all knopper ones, I think I've got more than enough for a while :lol:

 

[Honest John]

Good post custard, well done. I’ve noticed loads of oak galls recently, but never considered them useful, apart from making ink, which I did about 60 yrs ago! Incidentally, I’m on holiday in Cornwall at the moment, and I noticed the other day that the Sloes down here are in peak condition. Haven’t seen them so large. They are more like damsons. If I get the chance again I shall gather some oak gall. Thank you for posting.

 

[memzey]

These are a few of the ones I picked up today:

 

[Chris152]

I'd like to try using these. Are they just lying around on the floor at the bottom of the tree? I spent a fair while looking around a couple of oaks near me and found none, but saw what I think was one about 15 feet off the ground.

 

[memzey]

All those were just picked up off the ground. They do look very different to the ones Custard posted and I think they match the “Knopper” type mentioned above.

Interestingly some of them feel a little gummy. I imagine that they would need to be dried to be made into an infusion. What are the round ones like I wonder? Dry or gummy at first as well?

 

[Ttrees]

Just wondering, does the staining affect gluing atall?
laminating some timbers with tannin stained screw holes at the mo
Thanks
Tom

 

[Woody2Shoes]

Judging by the black tint in the cat's water bowl - under the tree - I think it's a fair bet that the knopper galls are full of tannin just like other types...

I've no reason to suspect that tannin staining, once dry, affects glue.

Cheers, W2S

 

[nabs]

I wondered about whether it affected glue too, although I assumed not just because it is a traditional solution.

It is extraordinary how deep black the stain is but it actually seems to penetrate very little (you can plane it one or two light passes). So you'd think something from the mixture would be left at or near the surface.

Once it is dry and you remove the powdery residue the stain can't be removed by wiping - does it anyone know what is going on chemically? Is it actually 'staining' the wood or something else?

 

[custard]

Just wondering, does the staining affect gluing atall?
laminating some timbers with tannin stained screw holes at the mo
Thanks
Tom

No, it doesn't affect gluing.

 

[thetyreman]

how long do they last for? will they ever go off? got them all in an airtight container

 

[custard]

how long do they last for?

I can't give you a specific time, but it's years and years.