Gum Arabic

This is the sap from acacia trees. Gum Arabic helps:

• Keep the pigment suspended
• Makes the ink flow properly from a dip pen
• Helps stabilize black chemical compounds

Without gum Arabic, you have a mixture that will separate and is difficult to write with. With gum Arabic, you have a stable, workable ink. (Thanks to Joumana Medlej for her elegant description of why we bother to use gum Arabic.)

Basic recipe

If you are working from lumps:

In a saucepan, combine equal parts gum Arabic and water. Cook to dissolve. The final solution should be the consistency of double cream.

Using gum Arabic for ink making

For each 100ml of plant liquor, add 10ml of gum Arabic solution.

You may need to adjust the amount of gum Arabic to suit your purposes. More for thicker ink; less for thinner.

Which gum Arabic should I use?

For botanical inks that are dark in colour: any food-grade gum Arabic is fine. You don’t need to spend extra on artist grade (liquid).

If you buy unprocessed lumps, you’ll need to cook in water to dissolve it. If you’re feeling outrageous, just pop a couple of lumps into the plant liquor. It will eventually dissolve.

You can also buy ground gum Arabic; however, this may contain bits of bark, which contain tannins, which could alter the shade of the ink you make.

If you’re making your own gum Arabic liquid: it should be “about” the consistency of double cream.

It will not be as clear as artist grade. For tannin-rich inks, this doesn’t matter.

Alternatives

For most of us, the Acacia tree is a far-away plant, which mostly grows in regions with questionable supply chains. If you'd prefer to avoid it, there are a few options.

Cherry tree sap - if you can find it. Unfortunately pine gum is not effective as it doesn't dissolve in water.