Gum Arabic: Tapped from the Acacia, Dried in the Air

Gum arabic is the hardened gum that oozes from gum acacias. Strip small pieces of bark from the branches and a clear mucilage oozes out, hardening in the air into rounded tears. Andrew Ure (1839) notes gum Senegal was gathered in November; the tears dissolve in water and bind watercolours and inks. The picture: raw gum arabic tears of different grades and the ground powder.

初学者

A few weeks on the tree

说明

Tap the tree

On a mature gum acacia, strip narrow pieces of bark from the branches with the tapping knife, without cutting into the wood.

此步骤所需材料：

阿拉伯胶树 (Senegalia senegal)1 个

所需工具：

割胶刀

手斧

Let the tears harden

Leave the tree. Gum oozes from the wounds and hardens in the air into rounded tears, often hollow on one side.

Pick and sort

Pick the hard tears into a basket. Spread them on mats in the sun, which bleaches them (Ure), and sort out bark and dark pieces; the clearest, palest tears are best.

所需工具：

篮子

编织席

等臂天平

Powder and store

The tears are brittle: crush them in a mortar and sift for a powder that dissolves quickly. Keep in a dry, closed jar.

所需工具：

研钵与研杵

粗筛

玻璃罐

Gum to binder

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Limits

Tapping and the gum's properties are from Wikipedia and Ure; the sorting and the solution strength are ours. The sources give no fixed waiting time between tapping and picking.