Sciencemadness Discussion Board

tannin source

beeludwig - 11-5-2019 at 12:48

I live in New England and I'd like to do an Iron Gall Ink experiment with my students. Sadly the Oak trees are distressingly free of parasites and there are no oak galls. Can I induce oak galls? I don't want to damage trees unnecessarily. Is there another source of tannins?

RedDwarf - 11-5-2019 at 13:07

Not quite the same experiment, but the same reaction - I dye oak black using a clear solution of iron oxide - stick a nail in water to rust, a little vinegar can help accelerate this, the iron oxide (rust) is not very soluble but there is sufficient in solution to react with the tannin in oak when you paint it on and turn the oak black. (I do it for the contrast in white and black timber when making furniture).

So you probably have sufficient tannin in a ground up piece of oak even if you have no galls.


[Edited on 11-5-2019 by RedDwarf]

Boffis - 11-5-2019 at 13:13

Have you looked at this thread?

http://www.sciencemadness.org/talk/viewthread.php?tid=104294...

I am not quite sure where SCwack lives but it sounds like the US.

beeludwig - 11-5-2019 at 13:26

Quote: Originally posted by Boffis  
Have you looked at this thread?

http://www.sciencemadness.org/talk/viewthread.php?tid=104294...

I am not quite sure where SCwack lives but it sounds like the US.


I didn't think there was enough tannins in leaves to make it worthwhile, but maybe I should try it and see. I wonder if spring leaves or fall leaves would be better.

CharlieA - 11-5-2019 at 13:46

Woodworkers "ebonize" (stain black) oak and other woods, by brushing on a solution of iron acetate made by dissolving steel wool in vinegar. I presume that the iron acetate is reacting with the tannins. Incidentally, old chemistry sets sometimes included tannic acid to be used in various experiments, which I can no longer remember.:)

mayko - 12-5-2019 at 07:48

brew stores sell tannin for winemaking. This is the brand that my local store carries:

https://storefront.ldcarlson.com/storefrontCommerce/itemDeta...

beeludwig - 12-5-2019 at 08:19

Quote: Originally posted by mayko  
brew stores sell tannin for winemaking. This is the brand that my local store carries:

https://storefront.ldcarlson.com/storefrontCommerce/itemDeta...


Wow, I didn't know that was a thing. I checked the website of a local shop and it has tannins for $4.00 an ounce. Even if I don't boil walnuts or something it might still be worthwhile just to see.

Mr. Rogers - 12-5-2019 at 18:47

I have gallotannic acid. PM if you're interested.

[Edited on 13-5-2019 by Mr. Rogers]

DraconicAcid - 12-5-2019 at 22:35

Surely you could also extract tannin from tea?

Felab - 13-5-2019 at 12:24

A long time ago I saw a video on making iron-gall ink from very OTC materials. In it, they brew a tea and they mixed it with ferrous sulphate pills (for anemia treatment). Then they added honey for consistency and it worked pretty well.

Unfortunetly the video is in Spanish, but the process is very simple.

https://www.youtube.com/watch?v=RkCEGAv2ktE

Also, you can boil oak bark or wood to get the tannins out.